HP 35s Scientific Calculator Reviews

• Best Scientific Calculator Available Today

  
  By A3AKMAEGRX371V on 2007-09-05
  This is a very nice high-quality scientific calculator from HP. The overall design and capabilities are similar to the HP 32SII (equation solver, unit conversions, etc.), but with several enhancements.
  
  Like many recent HP models, this calculator can work in either RPN or algebraic mode, but I use only RPN. The keyboard layout has been well thought out, with most functions being quickly available directly from the keyboard and a few lesser-used functions available through menus. The keyboard has a traditional HP layout and colors, and the keys have a nice positive feel. A very thorough and well-written printed manual is included.
  
  A new feature with this model is that each level in the four-level stack may hold a real number, complex number, or 2- or 3-element vector. Complex numbers may be entered very simply using the "i" key (or "theta" key for polar form); vectors are entered using square brackets. This design makes it very easy to manipulate complex numbers and vectors.
  
  The calculator includes 30 kB of memory, which is enough for over 20,000 program steps. There are 26 main memory registers (A-Z), six statistical registers, and 800 more memory registers available through indirect addressing. Another new feature of this model is TWO indirect registers, (I) and (J).
  
  A few cons: With previous HP calculators, there was a shortcut for entering exact powers of 10: for example, 10,000 could be entered as "E 4". For some reason HP has dropped that feature on the 35S, so you now have to enter "1 E 4". Not a major drawback, but kind of annoying since I used that shortcut a lot on previous models. Another nit is that the function to convert HMS to decimal hours is labeled HMS-> instead of ->H, which I haven't gotten used to yet.
  
  Overall, the HP 35S is a very well-designed calculator, and I would not hesitate to recommend it as the best general-purpose scientific calculator available today. In fact, I bought three (for home, work, and school).
  
  

• very good, but some room for improvement

  
  By A14J87NHJAGPYR on 2008-01-16
  I am a diehard RPN and HP calculator fan. I bought this calculator for the PE exam. HP calculators I've owned include HP41c, HP42s, HP12c, HP17BII, HP19BII, and HP33s. The HP35s is basically an HP33s with most the ergonomic design flaws and quality issues of the HP33s fixed, along with a few added enhancements. It's what the HP33s should have been in the first place. But, along the way, it also introduces a few design flaws of its own.
  
  Obvious pluses: The keys on the HP35s feel almost like the ultra high quality keys on the HP41c, not entirely there because the ones on the HP35s are flatter and have less travel distance, but very close. However, unlike those on the HP41c, some of the secondary colors on the keys are only painted on. How long would the paints last? It comes with a super nice semi-rigid vinyl case. The LCD display is fragile, but it seems to be dust-proof and has excellent contrast. The built-in metric/imperial conversions and constants library are also nice. One major enhancement over the HP33s is the ability for a program to refer to a line number instead of a label name during conditional branching. This feature allows the writing of programs that don't use up a lot of the precious program labels. The equation solver is quite powerful. It comes with built-in equations for solving 2x2 or 3x3 simultaneous equations.
  
  Obvious minuses:
  
  There are only 26 single alphabet program labels and only 26 variables, severely limiting the number of programs one can store, considering the somewhat large 30kB memory available(the HP42s only has 8kB). The manual has a good number of useful programs, but in reality one can store only a few of these programs on the calculator at a time due to the 26 program label limit. I can store more programs on the HP42s even though it only has 8kB of memory. In actual use, most of the 30kB on the HP35s will go untapped.
  
  It's a shame HP chose not to include multi-letter alpha-numeric capability as they did on the HP41c and HP42s. Instead of labeling a program that calculates the time value of money using a single letter such as "T", I'd much rather be calling the program "TVM" or "MONEY" or something easy to remember. The same one-letter restriction applies also to variable names. The listed battery life is on the short side. Two hours of use per day will last the batteries only about 9 months.
  
  Whereas the HP42s offers four types of curve-fitting and has capability to choose one with the best fit, the HP35s offers only linear regression. Also, unlike the HP42s, the HP35s doesn't have any built-in matrix capability to evaluate determinants, inverses, although it does have built-in 2x2 or 3x3 simultaneous equation solving ability as mentioned earlier. You can program all these missing capabilities in but you'll use up many of the precious 26 program labels in a hurry.
  
  The STO key which I use very often is now subordinated, requiring a shift key, whereas the "Mode" key which I seldom use is primary.
  
  The display has much more glare than other HP models I've owned.
  
  Although I will almost never use the algebraic mode except when writing equations, I must mention that its implementation on the HP35s is clumsy. On other algebraic calculators I grew up with, the number precedes a function key (such as COS, 1/x, log) and the function is executed as soon as the function key is pressed. In other words, even though they are algebraic calculators, their function keys work in postfix or RPN mode.
  
  The key sequence is
  
  45
  
  COS
  
  The value of 0.707 is displayed as soon as the COS key is pressed. It's very simple and intuitive. This is also how the functions work on the HP33s. But, surprise, this ain't how it works on the HP35s!
  
  On the HP35s, you have to start by first pressing the function key and then punch in the number and then press the Enter key to get the value.
  
  The key sequence is
  
  COS
  
  45
  
  ENTER
  
  The ENTER key works as the equal sign key in algebraic mode on the HP35s. Hitting the ENTER key now becomes mandatory to get an answer from just about any operation. Although this peculiar algebraic approach may make sense when writing equations, it's highly cumbersome when doing calculations on the fly, especially for someone used to the keystroke efficiency of RPN.
  
  I sometimes scratch my head trying to figure out why for the last 10-15 years HP kept churning out mediocre calculators, with each new one worse than the previous one. Why mess with winning designs and dumb them down to the level of TIs and Casios? Yes, the money is where the masses are and the masses are the high school and college crowd and they use predominantly TIs and Casios. Then it dawned on me that the sales execs, designers, programmers, engineers also have to somehow justify their existence by rolling out new models and discontinuing older but superior models. The HP35s seems to be a step to halt the march toward mediocrity. Does it succeed? Yes, mostly. Although the build quality is good, it certainly could have been designed better.
  
  Even though the STO key is now subordinated, the HP35s fills the need for basic everyday number crunching due to its ergonomic form factor and ease of use combined with a reasonably rich set of functions. The HP50g fills the need for heavyduty scientific/engineering use but is too clumsy for everyday basic number crunching.
  
  I'm sure as I use this calculator more, I will see more of both the pluses and minuses. And, if I were to rate this calculator in comparison with any Casio or any TI, I would give it 10 stars if I could. But I rate it in relation to what I expect an HP calculator should be and so I rate it 4 stars. If the HP35s came with more program labels and variables than just 26 of each (A to Z), multi-letter alpha-numeric data entry capability, matrix capability up to [5x5], 4 types of curve fits and best of fit, primary STO and RCL keys, I would rate it 5 stars.
  
  

• Not a bad calculator, for a change

  
  By A2PQBEWW2Q03V7 on 2007-10-16
  The 35s is the most interesting calculator HP's produced in a while. While I'm sure their intended market is the legions of dedicated HP users, even if you're not a lover of antiques you should give it a look.
  
  A definite improvement on the 32sII, and in general I would recommend it over purchasing an overly-expensive used HP. While the hardware isn't quite as nice the 35s should have a much longer battery life, and has more than enough memory to hold any reasonable number of programs.
  
  It's physically larger than a 32s and it's not really "pocket-size". Yet it's not that big compared to modern scientifics and the larger display is worth it.
  
  It feels very solid, except for a battery door which pops off a bit too easily. Lithium coin batteries are so much easier to deal with than watch batteries that I'll happily accept the tradeoff.
  
  The keyboard is slightly soft compared to older HPs but that's been easy to get used to. It has a definite click, good-sized keys with a large Enter key, and should seem quite familiar to HP users. Unfortunately it uses painted-on key symbols which I suspect will show wear rather quickly.
  
  Crisp display, easily readable from practically any angle. A huge improvement over the LCDs in HP's older models.
  
  It has RPN and algebraic modes, as well as an EQN key which allows algebraic entry while in RPN mode. Most keyboard functions have an EQN/ALG counterpart, and while algebraic formulas can be used in programs you'll still need to use RPN for conditionals and loops.
  
  The excellent mixed-base number support is a pleasant surprise. In algebraic mode you can easily enter a calculation in mixed bases without changing the current base. (This mostly works in RPN, but there's no way to enter hex A-F without switching modes.)
  
  Programming is similar to the 32s and much of the manual is identical--the only major change is additional memory. The 35s' overloaded keys and simple design make programming much easier than an RPL-based calculator like the 49g+.
  
  Why did it only get 4 stars? Two issues:
  
  No I/O. Being able to backup memory would make me a little happier and I've come to expect this from a modern programmable.
  
  And, RPN programs generally run only about as fast as on the 32s, making its programmability less useful than otherwise. After 15 years I expected to see at least a factor of five speed increase.
  
  In short: I like it, and I think you will too. In terms of price and ease of use it can't compete with, say, the Sharp EL series. (The new HP 10s is a real contender there.) But the HP 35s' programming capabilities set it apart from any of the inexpensive scientifics. If you'll take the time to learn RPN, you'll find writing programs is easier and more convenient than writing the same thing in a BASIC-like programming language.
  
  

• RPN is standard

  
  By AWPISPALUKMNK on 2007-08-29
  Tim C is as confused as Charles and is unable to spell my name even though it is printed in the review. I am holding an original HP-45 in my hand. If you type 2 Enter 3 Enter + you get the incorrect answer 6. Tim C's claim of an "error" in HP's implementation starting at the HP-32SII is completely false. I own an HP-32SII also. It works exactly the same way as the HP-45 which predates the HP-32SII by 18 years. I know what I am talking about. I own and use the HP-45, 55, 67, 29C, 41CV, 41CX, 48GX, 49G, 50G, 32SII, 42S, 28S, 50G, and 35s. I guess I need to repeat myself: ALL EARLY HP RPN CALCULATORS REQUIRE THAT YOU PRESS 'ENTER' ONLY ONCE. THE HP-35s FOLLOWS IN THIS TRADITION! Tim C should learn the history before he comments on it. Tim C should buy and use the product before he writes a review. The reviews by Charles and Tim C are misleading. Reviewer Charles has limited experience with RPN and has not explained it correctly. In general you should only have to press Enter once during a calculation with 2 numbers. This is true of the 48G also. Some calculators have a command line at the bottom that is separate from the x,y,z,t stack. For those you MAY press Enter twice but you don't have to. 2 Enter 3 + will work fine. On all the older RPN calculators you enter numbers directly into x and you should not press Enter twice. Again: 2 Enter 3 + will work fine.
  
  

• nice, nostalgic and useful

  
  By A26AZ371EZ8KEF on 2007-08-14
  The 35S is a retro commemoration of HP's history with the digital calculator. The black case and bevelled buttons are meant to hark back to those fondly remembered legendary early models which dazzled when they first came out. The 35S is also intended to address some of the peccadilloes that users complained about with the 33S. For those who balked at the crass silver case of the 33S, it's slanted buttons and its issue with the display, the 35S is the cure. The 35 packs a few more features as well.
  
  
• Almost but Not Quite Yet
  By A1AKAC8VSCS824 on 2007-08-24
  The HP 35S is inntended to be a tribute to the original HP 35, the first hand held scientific calculator, introduced 35 years ago.
  
  The new calculator is IMO a huge improvement over other recent HP calculators as the keyboard is much more readable and the display contrast is excellent, with adequate size radix indicators. The keyboard has good tactile feedback in the classic HP tradition. The current units cover window on the LCD is very reflective however and needs improvement.
  
  It has 32K of memory, more than adequate for this class of programmable calculator without any external program storage capability or computer hookup ability for program upload and download.
  
  Program structure is directly descended from the HP 32s which places considerable limits on the number of programs that the calculator can hold and prevents giving them longer than single letter names. Program execution speed is about the same as the HP 42s by my testing, adequately fast but not a speed demon. I was personally hoping for program structure closer to that of the classic HP 41C and 42s units.
  
  At least one minor bug has shown up with obtaining the Cosine of angles >= 89.999 degrees but < than 90 degrees. It is a loss of accuracy in the last 3 or so digits of the answer compared to the correct answer. Also no rectangular <> polar conversions are included.
  
  Overall though in RPN mode the unit is the best true RPN Scientific calculator that HP has offered since the HP 32sII and 42s IMO. I am hoping it will eventually be the basis of an upgraded unit that is closer to the 42S in functionality.
  
  I note a couple of reviews have errors in that they do not differentiate between HP's RPN and RPL calculators. ALL RPN calculators will give a different answer to 2 Enter 3 + (5) than they will to 2 Enter 3 Enter + (6) with answers shown in parenthesis. This dates back to the original HP 35 (First RPN) and 28C (First RPL) as I still have one of each in operating condition and checked this.
  
  RPL has an input buffer and the examples given above will both give the answer "5" as the Enter before the "+" moves the input value from the input buffer to the lowest stack location, clearing the input buffer. "+" in RPL will either add the two lowest stack locations or the lowest stack location and the input buffer if it is not clear.
  
  In RPN the Enter duplicates the value in x (the bottom stack register) into the next stack register and + always adds the first and second stack registers. Numbers are input directly into the lowest stack register in RPN calculators.
  
  I own about 15 HP calculators from the oldest to the newest and ALL of the RPN units work one way and the RPL units work the other way.
  
  An RPN Lover
  
  
• Welcome back HP
  By A3P9KTM581UC4D on 2007-09-29
  I have been using HP's low to mid priced calculators since I bought an HP21 back in 1977. HP lost its vision in recent years with their calculators, abandoning RPN in their lower priced models and producing disasters like the HP6s and the HP33s. The HP35s is a definite sign of improvement. In spite of the gripes I list below, I consider this a good calculator I look forward to the HP35sII.
  
  What they got right:
  
  Good physical design, with good key lettering and key action. Not like their recent designs that are about style instead of clarity and ease of use. Similar to some of HP's older (and better) calculators. The key action is still not quite up to my favorite, the HP32s.
  
  Errors:
  
  The values for COS and TAN calculations near 90 degrees are incorrect in the last few digits.
  
  Deficiencies:
  
  The exponents of displayed values are off screen when the DISPLAY mode is set to ALL or using "ENG ->" or "<- ENG".
  
  You must use 3 keystrokes to enter "h", "b" or "o" after non-decimal number entry. You should NEVER need to do this to any number being entered in the base of the selected mode. I can see were it would be handy for entering nummbers in an alternate base, but only then.
  
  Keys for hex digits A through F are unlabeled in RPN mode and require two keystrokes in algebraic mode - bad design.
  
  The thousands separators do not appear during digit entry; only after ENTER or an operation do they appear. This worked on older HP calculators.
  
  
• Disappointing--Too Many Failings
  By A2JR10TRIJXJ3R on 2007-08-28
  I had high hopes for this calculator, but now that I have it in my hands I'm quite disappointed.
  
  1. The keys are mush. This is a major failing. The tactile response of the keys on HP's professional calculators has always been an important aspect of their ease of use. The HP 35s, however, has mushy keys no better (and maybe worse) than cheaper scientific calculators from Casio or Texas Instruments. Incompetent design at HP now seems to be the norm in their calculator division.
  
  2. The calculator is too wide and badly shaped to comfortably hold in the hand. It's deceptive in photographs, but the 35s bulges slightly towards the middle. This makes is slightly wider than my 48G, which is a big graphing calculator. The 35G feels unwieldy even though it's advertised as a pocket calculator.
  
  3. It uses non-standard batteries. My 48G uses standard AAA batteries, but the 35s uses button batteries that you'll have to hunt for to replace. This is a poor decision on HPs part, creating another hassle in addition to the poor ergonomics.
  
  4. The RPN entry is implemented incorrectly, and it is inconsistent with other HP calculators. This is insane. If I type 3 ENTER 2 ENTER + on my 48G then I get the answer 5, which is correct. If I type that in on the 35s I get the answer 4! Why? Apparently when I enter the number 2, it keeps two copies in the number: it moves a two into the register but doesn't remove it from the entry line so it ends up adding 2+2 instead of 2+3. This is absurd, confusing, and will lead to wrong calculations. It's inexcusable that HP would change it's implementation of RPN between scientific calculators--same company and same product line! I guess they're trying to compete with Microsoft in being hostile to users.
  
  5. The display is of poor quality. The numbers are chunky and pixelated, and with better design HP could easily have fit a 3-line display on the 35S. My 48G displays 3 lines in the same space as the 35S displays two, and the display on the 48G (over ten years old!) is sharper and easier to read even though the numbers are slightly smaller on screen. The 35S looks like a digital photo magnified beyond what the resolution will bear. This is 2007: I can get a cheap MP3 player with a better screen than this. Designing a good LCD screen is not rocket science, but the incompetence at HP is profound.
  
  I'll probably keep the 35s since I need a calculator in my home office, and I don't want to spend the money on another HP graphing calculator. But the 35s has little to recommend it, and considering all of HP's hype about commemorating the heritage of their scientific calculators, the 35s is a travesty. HP should be ashamed, and the 35s deserves to fail in the market place. I'm disgusted with what they've produced compared to what they could have produced.
  
  
• Programmers & software/firmware engineers beware!
  By A2UOOG4V28R3AX on 2008-01-30
  HP 35s
  
  
  
  Programmers & software/firmware engineers beware! If you do any base conversions and arithmetic please read this before considering this otherwise worthy calculator. In *all* previous HP calculators to do say hex addition (Ex: 12F + E9A) you'd simply do this:
  
  1. Select hex mode: SHIFT BASE HEX
  
  2. Enter the first number: 1 2 F ENTER
  
  3. Enter the second number: E 9 A
  
  4. Press + (total 11 keystrokes)
  
  
  
  Not so with the 35s! Here's the drill straight from the example on page 11-5 of the manual
  
  1. Select hex mode: SHIFT BASE HEX (so far so good...)
  
  2. Enter the first number: 1 2 1/x SHIFT BASE 6 ENTER
  
  Explanation: Although there's a key labeled "F" you don't use that one when entering hex numbers - you use the 1/x key to enter F!!! After you key in the hex number you still have to tell the calculator you've entered a hex number (even though you're in HEX mode (WHY??)) by pressing the sequence SHIFT BASE 6 - that puts a lower case "h" after the number.
  
  Continuing on:
  
  3. Enter the second number: y^x 9 SIN SHIFT BASE 6
  
  4. Press + (total 17 keystrokes!!!!)
  
  
  
  So the 2 main questions are:
  
  1. Why use the SIN, COS, TAN, SQRT-X, y^x and 1/x keys to represent the hex digits A, B, C, D, E and F when there are keys on the calculator labeled "A", "B", "C", "D", "E" and "F"?!?!?!?!?
  
  2. Why do I have to tell the calculator that's currently sitting there in HEX mode that I've entered a HEX number?!?!?!? In fact if I key in a hex number that contains an alpha digit and press enter I get "SYNTAX ERROR"!!!
  
  
  
  So in a nutshell - If you're looking for a calculator do to base conversions and arithmetic even occasionally this is *definitely* not for you.
  
  
  
• Not the same as the original HP calculators
  By A2YNF8D4ADUPD9 on 2007-08-21
  If you're like me and have "grown up" on HP calculators and were think "This is it! HP is back!" let me be the first to tell you that, no, HP is not back. The calculator feels a bit more fragile than the earlier generation and is missing some of the well thought out HP calculator innovations that the earlier alphanumerics, such as the legendary HP-41, hhad. The display does not show the function key you pressed unlike the HP-32s I own. Better yet the HP-41 showed the function and if you made a mistake in hitting the wrong function key, you simply held the key down for 2 seconds the function was nulled.
  
  UPDATE: Day 2. Now the calculator has hung-up with SYNTAX ERROR. I tried all the obvious keystrokes without resorting to the manual to no avail.
  
  
• Great Calculator
  By A1N2OFHLJD3CDH on 2007-09-08
  I've been using HP calculators for almost 20 years and am very happy with this one.
  
  The keyboard layout and feel are both absolutely perfect in my opinion. It retains the HP tactile click without having stiff keys with long travel, which is my only problem with the new HP50g (otherwise awesome calculator). I have a big, nasty equation that I used to test my speed with my calculators. It took 30 sec. on my 33s, 25 sec. on my 50g, and 22 sec. on my 48G which I've been using for 10 years. The very first time I cranked it through my 35s, literally <2 minutes after inserting the batteries, it only took 23 sec. This calculator is optimized for cranking through big hairy equations. To me, that's what an engineering calculator is for! I have Mathcad, C++, Matlab, and Mathematica for all the stuff that graphing calculators do, but that's another story...
  
  Pure RPN does take a little getting used to if one is used to the graphing models' RPL, but the 35s implementation is correct. My previous calculator was a 48G, so I found the 4 level stack to be slightly irritating. Took an hour or two to completely get over that when I bought my 33s a while back.
  
  I actually like the tiny batteries instead of AAA because this cuts down the weight of the calculator. AAA batteries in the 35s, which is a very elegant little calculator, would've been insane. Also, what's the alternative? Feeding AAA batteries, 3 or 4 at a time, to a graphing calculator once a month?
  
  Unless it dies on me, I think I'll be very happy with this calculator for a long time.
  
  
• A Step in the Right Direction
  By AP1FWNGNWO8JM on 2008-01-04
  I bought the original HP-35 back in 1973, when it cost $395. The "new" HP-35s is better in many ways, but it still misses as a direct replacement for that classic calculator. One of the design goals of the original was that it had to fit in a shirt pocket, and it did. Oddly, the new version is larger than the original, but it does weigh less. HP made the new keyboard larger with larger keys, but IMO the old HP-35 keyboard was easier to use because it was more legible and less crowded. The HP-35s is programmable, but it has no way to store or transfer large user-created programs off of the calculator. That is the main reason I didn't rate it higher than three stars.
  
  I'm glad to see HP making RPN the primary entry mode again. Maybe they'll follow this model with a "new" version of the HP-45 and add a USB port for data and program transfers.
  
  Post Script 2-18-08
  I've now had the calculator for a couple of months and find its annoyances outweigh the advantages. The keyboard's poor legibility and odd layout frustrate me every time I use it, and simple functions like clearing a register or a syntax error require multiple keystrokes -- arrrggg! My trusty and worn HP15C is back out of the drawer. Adios HP35s.
  
  
  
• HP Calculator Comeback
  By A1ADZ1TFZCP6SM on 2007-09-04
  The new HP 35S is a big improvement over the HP 33S and works well as an inexpensive RPN scientific calculator. Good keyboard feel and clear display.
  
  
  
• Great!
  By ASLGZP0H1OC9I on 2007-09-22
  HP has done well going back to what works. This is a vast improvement over the 33S with it's poor key layout and hard to read display. The 35S buttons have that classic "HP" feel, the layout is easy to navigate, and the display is nice and easy to read. As a practicing civil engineer, this calculator just plain works - just what I need without a lot of features that I would likely never use.
  
  
• finally, HP makes an RPN calculator like the old days
  By A3MHXKJN9ZT2Q0 on 2007-08-30
  I used to have a 32SII but lost it many years ago. Since then, I've been looking for a replacement RPN calculator. While the HP33S is RPN, I'm not a big fan of the key configuration. Finally, HP releases a calculator more like its previous versions. If you're a fan of RPN, highly recommend this calculator.
  
  
• HP Celebrates 35 years of Innovation
  By A34R39IAPS2OEE on 2007-10-06
  When I found out about the new HP 35s, I knew I had to get one, even though my HP 32sII works just fine. My first HP calculator was the HP 15C, built like a tank and very practical in use. It was the best engineering calculator in the 80's. However, I lost that calculator many years ago.
  
  Although I missed the HP party in San Diego, CA, I purchased the 35s as a sort of "thank you HP" for several reliable, high quality precision tools that they had created through the years. I just received the 35s this week. The key layout reminds me of the older C series calculators and is a positive improvement over the cluttered 32sII key layout. If there is one change I could make on the keyboard layout, it would be to have a separate STO key. To my eyes, the annunciators seem a bit too small on the display. Also, the 35s LCD screen has more reflections than the screen on my 32sII; with indoor lighting, it is more difficult to see the numbers on the 35s.
  
  I'm not sure how to benchmark calculators; however, during some calculations, such as nCr (n=800, r=400), my 32sII found the result faster than the 35s. Other times, such as integration of the bessel function with x=2, the 35s was slightly faster. Again, these were subjective tests, nothing scientific about them.
  
  I doubt I will use the 35s to its full capability (i.e. programmable features) unless I catch the RPN programming bug. Despite my display preferences, I hope the 35s sells well and will encourage HP to design future calculators with the same user-centered design approach and reliability that they have been famous for.
  
  The 35s is a well thought out machine. I like the case that is supplied with it. The manual appears thorough (similar to the 32sII manual) and contains a few grammatical and detail omissions. HP should have provided an electronic copy of the manual on the "bonus" CD video. Perhaps HP will provide a copy for download.
  
  The last time I was excited about a calculator was when I purchased a 15C in 1985. I'm glad I purchased this new 35s and am looking forward to future scientific/engineering RPN calculators from HP.
  
  
• Thank God!
  By A106HP8MDJZZFX on 2007-10-03
  After using the HP 33S, 49G+, and 50G, I was beginning to worry that I would never be able to buy a new calculator that was even close to as usable as my other, older HPs. It looks like HP has finally decided to listen to their customers, however, and my hope for the future has now been restored.
  
  The first thing you'll notice about this calculator is that it's not curvy, bright colored, and generally ugly. I think it's pretty safe to say that this is the best looking scientific calculator that is currently on the market.
  
  The big enter key is finally back, and unlike HP's other recent calculators, the thing actually starts up in RPN mode, and has a manual that was written for RPN mode. It has an appendix for algebraic in the back (I'd really like to see them get rid of that altogether, but one step at time). Despite some false claims by other reviewers, the implementation of RPN is correct and is consistent with all of HP's other calculators with a 4-level stack (the non-graphing ones).
  
  The button action is also a lot better then that of my 33s, 49G+, and 50G. The shape of the buttons is comparable to the ones on my 41CV and 28S (both of which have really nice buttons). The feel is still not quite up to par with the 41 and 28, but I'd say it's about equally nice as the feel of my 32SII and 48GX. I don't know how long they'll hold up, as I've only had the calculator for a couple of days, but hopefully they'll last as long as the ones on my 41CV (my oldest HP) which are still going strong.
  
  The screen has better contrast and is easier to read than the screens on my 48GX and 28S.
  
  
  Here's hoping we get a graphing calculator with some of the same design concepts applied (a 51G?) instead of more of that other nonsense HP has been pushing recently.
  
  Highly recommended.
  
  
• A breath of fresh air
  By A21H5CNAREI5BZ on 2007-12-09
  Thank goodness. An HP calculator that *looks* like an HP calculator, that *works* like an HP calculator and doesn't try to compete with Texas Instruments under TI's rules. HP has remembered that they wrote the book on calculators. It's been a long time coming.
  
  
  I truly appreciate the feature set on this calculator. It includes excellent support for complex numbers without the need to use two stack levels to hold real and imaginary parts (as did the 33s). The keyboard is remarkably uncluttered considering the number of functions exposed. Functionally-relate keys are close together (another failure of the 33s). In many ways, this calculator embodies the Principle of Least Surprise.
  
  The new vector math features are interesting. I would have liked to see a cross product feature (dot product is available), but there is a program in the manual that works well enough. I think of vectors as a subset of matrices (you may feel different) so I was surprised to see vectors without matrix support. The unit provides access to 800 indirect registers, though, so I expect to see some interesting matrix programs to appear in a solutions manual in the future.
  
  I'm an RPN guy, so I didn't play with the algebraic mode too much. It seems to follow the two-line symbolic method where the expression is written in the upper line and there is no answer until you hit the equals key. I truly dislike calculators that work this way. Perhaps I'm addicted to intermediate results.
  
  The manual assumes you're using RPN mode for nearly everything. Use of the algebraic features are mainly described in an appendix. HP still seems afraid that they can't sell an RPN-only calculator; I believe that they include the algebraic mode as a user-reassurance feature more than a serious mathematical capability. (Dear HP: How many "classic" HP-12C's do you sell? You know, the gold-toned ones. I still see them on the shelf despite the new platinum editions. They sell well, and they're RPN-only! Take a clue from success!)
  
  The only feature addition I'd like to see is programmable hot keys. Ever two or three would be swell. To run program at label "A", you need to hit [XEQ] [A] [ENTER]. Not a tragedy I guess, but think about it ok?
  
  If you've been turned off by HP's recent offerings, give this one a try. I think you'll be pleased.
  
  
• Proper successor to 32SII
  By A2KQD49M8KQ8XJ on 2008-05-08
  Background: I have a 48G, 32SII, 33S, 12C, and now 35S. I have also used the 32S. I have mostly used the 32SII, but have switched to the 12C to balance my checkbook.
  
  The 35S is much better than the abortion that was the 33S. It gets back to the standard grid layout, easily readable labels, and overall arrangement of the "good old calculators" as exemplified in my mind by the 32SII. In this review, I would just like to nit-pick at various things in the hopes that HP engineers might read these little criticisms and maybe fix them in a later version. But here is my plea: don't make a new version just to fill some business need to have a new model every year. You can do that with the graphing calculator and the mainstream Algebraic models, but please don't mess with the hardcore science and engineering calculator models without good reason. Think about it: there is a reason why 32SII's are still going for $150+ in auctions. There is also a reason why you have been able to sell the 12C unchanged for so many years. Come to a design, "perfect" it and sell it year in and year out. I can see this happening with a 35SII which corrects the minor mistakes of the 35S. Or even just start making the 32SII again and sell it for $100 or whatever it needs to cost in order to make it to the previous quality standard. It is wonderful to see HP admit its mistakes with the 33S and take a step back to the heritage designs. Anyway, to the nit-picking:
  
  1) I don't like having the shifted labels on opposite sides of the keys. The orange shifted functions are printed above the keys, while the blue shifted functions are printed on a beveled, lower part of the key itself. This makes it hard to scan for the function I need, as now I have to read 3 lines (top, main function, bottom) instead of just 2 like on the previous scientific and graphing designs like 32SII, 33S and 48 series (although it represents a crossover from the older 12C and similar designs). This is especially troublesome on the unit conversion shortcut keys. I am fine with having the alphabet labels on the beveled edge.
  
  2) Arrow keys and menus (holdover complaint from 33S). While arrows are somewhat more intuitive, I prefer the 32SII style of being able to select every option with a single press instead of navigating with the arrows and then hitting "Enter". Mercifully, there are numeric shortcuts for most menu options, but this is not the case for verification of "Y" and "N" when selecting Clear -> All. Given the key layout, and given that there are usually 4 options displayed per screen, it would be nice to have each option mapped to the top row of keys, A, B, C, D instead of 1, 2, 3, 4, since it is harder to look from the screen down to the bottom of the calculator than to the row right below the screen. I understand that on multi-page menus the later options are numbered 5, 6, ... which makes for quicker selections for those who have the menus memorized, and I don't want to get rid of that; instead I suggest the A, B, C, D as an additional way of selecting a menu option.
  
  3) I would like to have separate "STO" and "RCL" keys, and have both of them also labeled with a variable letter. One of my favorite shortcuts on the 32SII was hitting "STO" twice quickly, storing to the "G" variable and then being able to quickly recall it with a rocking two-finger motion on "RCL" and "STO". "G" and "H" were my most often-used variable labels, as they were so handy with quick manipulation of the "STO" and "RCL" buttons.
  
  4) On a scientific calculator, I feel that having a dedicated ln and e^x is important, with the shifts respectively being log and 10^x. I understand and appreciate the logic of the placement of these 4 functions on the current 35S, but still they should be dedicated keys instead of shifted.
  
  5) MODE doesn't deserve its own button. I would much rather have separate STO and RCL than have a non-shifted MODE. I also agree with the previous comment about having all the menu buttons in the same place. I suppose that having the BASE button within the main function area is a bonus, but it doesn't make up for the horrific implementation of base arithmetic.
  
  6) Having to page over to display exponents? The previous 32SII, 33S etc. had it right: show the entire exponent, and if we want to see the entire mantissa then we will have to press "SHOW" (shifted on "ENTER" as always).
  
  7) Lack of a printed manual. Apparently HP originally included a printed manual, but now (just received mine from Amazon today) they are just including a CD with the manual on it in PDF format, along with a very brief "Quick Start Guide". While I can obviously understand the reasoning here (added cost, waste of paper and packaging space, transportation costs, etc.) I would at least like the option to buy a printed manual on the HP website or something.
  
  EDIT: Having used the 35S regularly for a couple of months now, I would like to add a couple of more gripes:
  
  8) Changed decimal-point/fraction functioning. On the 32SII, if I wanted to enter "3/7" as a fraction on one line, I could key 3 . . 7 (decimal point twice between 3 and 7) and be done with it. On the 35S, it requires me to key 0 . 3 . 7 (in other words, in the "a b/c" formulation, the "a" is now required, and if "a" is 0 you can't get around it by hitting the decimal point twice). I can't see any benefit to this change.
  
  9) Occasionally I will get "soft" or "missed" keypresses. This seems to be the case most often with the decimal point. E.g. I will enter the number 215.37, but it will show up on screen as 21537. But sometimes it will happen with a digit key or even the ENTER key. I have been using HP calculators for 10+ years now, and never had a problem with this using any other calculator, so I don't think it is my technique that is the problem.
  
  
• HP gets it right at last
  By A1KMX9A5KCBJAV on 2008-03-23
  After blundering around for several years, HP Calculator Division comes out with a simple, powerful, well-designed, easy-to-use calculator that's not trying to be a PC. If you're a working engineer who needs something in between a pencil and a PC, this is the tool for you. People call it "retro", but I just call it going back to a classic, proven design. Big plus on the 35s is its complex number calculating and formatting capability. Even if you are not an RPN geek, this calculator is worth a look. The ALG mode is not just an afterthought on this machine. It is well-designed and even outshines the RPN mode in a few areas. Highly recommended.
  
  
• HP 35s A big step in the right direction for HP
  By AXG01V2C7LV1X on 2007-11-15
  Key spacing similar to the 11 and 15c series. New menu system keeps your fingers at the numeric keys instead of jumping to the top. Automatic Rectangular to Polar conversion works great. Keyboard key click/feel is (IMHO) even better than the 11c and 32sII, and about the same as the HP-41CV.
  
  LCD screen seems a little sensitive to touch. In wiping some dust off of the screen, it will darken in the areas being wiped but goes away immediately, so no harm done. Just makes me worry a little. Only time will tell.
  
  I am a Land Surveyor. When I found out the R->P (Rectangular to Polar conversion) key was missing I really though HP had a screw loose. What I have wonderfully discovered is that it is now even simpler to inverse between coordinates and get readable results. Example: Northing [i] Easting [Enter] Northing [i] Easting [-]. The result on the screen is the Dist@Angle in decimal degrees. By hitting the [<-][ARG] keys it strips out the Angle for conversion to DMS. No more subtracting the Eastings and Northings separately, entering it backwards (Easting [Enter] Northing) then using the R->P key. I will write another review once I get into programing some of my curve (vertical and Horiz), Traverse, and intersection programs into it and will let you know how those run and the ease of programing it. (GET THIS CALCULATOR, AT ITS PRICE POINT, IT IS A STEAL)
  Once the word gets out about this 35s calculator, expect the prices on your favorite Auction site to really drop on the 32sII.
  
  
  
• back-to-back jacks from hp!
  By A3HZ7JKOU748TF on 2007-11-25
  another homerun from hp! I hope this recent trend continues. The 50g is an excellent graphing calculator but if you want a scientific calculator alone, the hp35s is the one to get. The feel is SOLID (like the hp of yore), the display is superior, and the keyboard look and feel is absolutely fantastic. Powerful programming as well.
  
  NOTE: You also get a dvd in the package that gives a brief history of hp calculators (two stories on the dvd --- the space shuttle crew using their hp calculator to calculate the accurate re-entry angle and the hippo digesting the zoo worker's hp calculator are priceless!).
  
  
• The HP35s, flagship HP scientific calculator makes a blockbuster comeback
  By A3MAFS04ZABRGO on 2007-12-16
  The HP35s is the second HP scientific calculator which I have purchased since X'mas 2003. The first is a HP20s which I am still using.
  
  Having used HP's financial calculators for over 14 years and value for money but forgotten Casio scientific calculators during school, my first impression of the HP20s is my benchmark of HP scientific calculators, in terms of functionality, build quality and reliabilty. The only problem with the 20s is no RPN input function - something which was very non-HP since I have been a HP12c user before trying out the HP scientific calculator line.
  
  With a fresh out of the box HP35s on hand, my old benchmark for HP scienfic calculators has immediately switched over to the HP35s on the first day of use,side by side with the 20s. I am very impressed with the HP35s, HP has made a most timely comeback in this one.
  
  In my opinion, the recently released HP35s should be the long awaited really NEW flagship HP programmable scientific calculator in current production which comes with RPN input in years. The large ENTER key is a welcomed sight for many RPN fans, this retro HP looks and handles like a vintage HP gem - a sign that HP may be heading back to focus on where its old niche is.
  
  My HP35s set comes with a neat cushioned zipper pouch dubbed a "hard case" and a friendly user manual which is a maths revision course by itself. In some markets, a commemorative CD is included in the package for diehard fans. A clear, comprehensive and well written user manual accompanies the HP35s and as always, another hallmark of HP excellence.
  
  For the hopeful fans, the arrival of retro RPN HP35s may yet inject new life and resurrect the HP scientific calculators line. Should the HP35s becomes a runnaway success instead of a 35th anniversary commemorative model for the HP35, it would be quite a comeback by HP to this product segment and would give its closest competitors a real run for their money. There is hope that HP fans may see a revival of HP's line of RPN scienfitic calculators with the HP35s winning over some converts.
  
  Not only does the HP35s looks retro and commemorates the HP35, it was resurrected with the kind of solid build quality and execution which was absent for many years since HP outsourced its handheld calculator production to OEMs.
  
  For the equivalent cost of the HP35s, I could have purchased 2 sets of similar performance Casio scientific calculators for the same price with some loose change left as lunch monies. The price premium for a HP35s, seems worthwhile because it would probably out last its close Casio and TIs competition. By then, the seasoned HP35s user would most likely get a 35s replacement if it ever dies a dozen years in the future.
  
  However, with the HP33s still in production, fans should not expect HP to release newer models with RPN in this product category to compete with TIs, Casios and Sharp at the lower "student" price range of the new HP10s. The HP35s would likely remain a flagship by which other models in the line would be benchmarked against.
  
  In a nutshell, the HP35s has ALL the X-factors of a HP modern classic in the making. I have purchased the 35s mainly because its RPN and I like its retro look. Toying with the HP35s, I am convinced that HP has done a wonderful job on the HP35s, their effort lone is worth 4 stars. It it should be a Hi-FIVE, however, I am not a rocket scientist and my calculations may not uncover any bugs in the HP35s so I should reserve 1 star just in case some bugs in the HP35s would surface.
  
  Every HP Calculator fans should have a 35s in their private collection, this is the only calculator which rocket scientists, RPN fans would love to have as a gift this X'mas '07.
  
  
  
• Excellent Calculator
  By A1609A24WYPVU2 on 2008-02-02
  I bought the TI-89 because I thought I could write programs on my computer and transfer them, but couldn't get it to work that way. The TI has many more functions than the hp 35S, but it takes more button presses to do things. TI for example converts from any unit to any compatible unit, and if it doesn't have it you can create it, but it takes several clicks to get there. The 35S converts between 5 different metric and eng units with just one click. The hp does mixed numbers very easily, whereas the TI I could only figure out how to get fractions or decimals. The solver function in the TI is a separate program, but is a button on the hp, again less clicks. The TI can differentiate and I think integrate, but this hp only does integrals. Even doing integrals is more than I expected, but differentiating is helpful if you're doing a lot of proofs.
  I had an hp 11C for about 20 years and it was stolen last year which was why I bought the TI. Though there were a couple years where I didn't use it very much, I never had to replace the batteries. I don't know if the battery life on the hp 35s will be as good, but I can tell you the batteries frequently go dead for undergrad students with TI graphing calculators in the middle of tests, and they take 4 AAs.
  One reason I ordered the 35C was because the buttons looked similar to the 11C, and as it turns out they have a similar feel too (missed it by that much). I have a problem with the TI skipping button clicks every once in a while, I don't know if I press two buttons at once sometimes or what, but for some reason I didn't have the same problems with my 11C, and the buttons on the 35S have a similar feel, and so far I have not had that problem with the hp 35S.
  Programming the 35S is similar to programming the 11C, possibly a little better I think. One really good thing about RPN calculators I've enjoyed over the years is that nobody asks to borrow it because they can't figure out how to use it.
  I like the plastic slide cover you get with the TIs better than the leather looking zipper cover on the hp. The leather cover looks really nice, but the slide on the TI is more convenient.
  The user guide that comes with it is a good size with a couple hundred pages and is very complete. I wondered why they put left and right arrows on the blue and yellow buttons, but I think it is because it makes the user guide easier to read since it is black and white.
  Overall I like this better than my 11C because it has some very helpful features, particularly the solver and unit converters, and I like it better than the TI because I can get useful work out of it faster with fewer button clicks, and because it is smaller and lighter than the TI-89. It is of course comparing apples and oranges somewhat because the TI-89 is a graphing calculator, but I found that I don't need the graphing capabilities.
  
  
• High-end programmable calculator for nostalgic HP users
  By A253V7WJ5OE93T on 2008-01-25
  HP made this model to celebrate 35 years of HP calculators. That means the HP35s is a bit nostalgic in that it's made to look and work somewhat like HP calculators of the 1970s (but it's a lot more powerful). If you have never used an HP calculator and are just looking for a simple-to-use scientific calculator to get you through your algebra course, this is not the right gadget.
  
  What I like:
  
  - ergonomic, good-looking, solid design, nice keys
  
  - RPN is the preferred mode of use (i.e., "1 ENTER 2 +" instead of "1 + 2 ="). Algebraic entry is also relatively well supported, but has some problems.
  
  - lots of features
  
  - lots of memory for programming
  
  - HP-style keystroke programming is very intuitive and powerful (for a calculator)
  
  What I don't like:
  
  - the length of a number at full precision exceeds the width of the display, so you either have to scroll to see a result or limit the number of decimals. Neither works very well. For example, computing 1/7 will either give you 0.1428 (limited decimals) or 1.42857142857E- (seriously, the exponent is off-screen, so without scrolling you won't know whether it's .142 or .0142 or maybe 142000...). Scrolling is especially painful in algebraic mode, where it requires TWO keystrokes to scroll one screen
  
  - support for number bases (hex, binary) is very cumbersome and uses unlabeled keys for hex digits (A..F). Hex arithmetic is very hard to do.
  
  - if you also own an HP graphing calculator (HP48/49/50) which uses RPL, the RPN entry is confusing, because it is slightly different (one requires to press ENTER more often than the other).
  
  In summary: this device is great if you've used other HP calculators over the last 35 years and need a standard (programmable) calculator. If you need graphing, symbolic math (CAS), financial calculations, matrices, etc., you should consider an HP50g.
  
  
• Not at all impressed...
  By A19UGGINFEVGX2 on 2008-03-07
  It's far, far from perfect. The low resolution display is tough on the eyes under less ideal conditions. Why didn't they make it as crisp as that on the HP-15c? It's actually difficult to see the decimal point. And sometimes an oblique shadow under the decimal point makes it look like a comma!
  
  The display of complex numbers leaves very much to be desired due to lack of any spacing between real and imaginary parts. And the R-theta representation is even worse --- the theta looks almost like an 8, forcing you to carefully parse the displayed character string to determine where the angle starts. What were they thinking?
  
  The thin texture of the keys and the small, dimly painted graphics, coupled with the calculator's very light weight, destroy the superb quality feel of earlier HP calculators.
  
  The semi-rigid protective case is just odd enough to be uncomfortable. It's actually awkward to hold and use the calculator when it's mounted in its case.
  
  So... the HP-35s is getting returned and I'll continue using my trusty old HP-15c until something better comes out of HP.
  
  
• good calculator, some flaws
  By A2OCHD8BI87VMB on 2007-10-14
  This calculator is good in several ways: RPN entry, keypad with great tactile feel and large keys, clear display. However, HP missed an opportunity to make this an outstanding calculator:
  
  a) Edges aren't straight. I could use my trusty old HP 11c as a ruler because of it's handy straight edge. The slight curve in the sides of the new 35s is neither useful nor aesthetically appealing. All calculator edges should be straight. In fact, why not go further and etch a ruler pattern on the side?
  
  b) No separate keys for hex digits A-F like the good old 11c. Instead, one has memorize that in hex mode, sin = A, cos = B, tan = C, sqrt = D, y^x = E, 1/x = F. Who would remember that 1/x = F?
  
  c) Useful constants such as inches/meter (39.37), standard formulae for volume, etc aren't printed on the back of the case.
  
  Another flaw I find annoying: sin(pi) does not return zero, but -2.067e-13; similarly cos(pi/2)=-5.1e-12. It is not a fact of life that numerical approximation of trig functions will produce this error. A Casio FX-115 reports sin(pi) = 0.0 and cos(pi/2) = 0.0. Even Microsofts's Windows Calculator says sin(pi)=0; cos(pi/2)=0.
  
  
  
  
• Glad to See H/P is Listening
  By A3CMH6AQVQFOIV on 2007-10-28
  I purchased a 35S for my son and deemed it as the calculator he will happily use for at least the next 6 years. Everyone has attested that the 35S is a sign that H/P has gone back to their roots. I agree with the statement with the only reservation being the LCD display. There's just something about it that makes me feel like the pixels could've been tighter and with better font numerations.
  
  Aside from that, this lil machine is a testament to good H/P design and going back to "what works". My first calculator was an H/P 35 in 1975. The last one I purchased "new" was the H/P 28S. Since then, I've gone back to the Voyager models and still use a Top Cat (H/P 97) for work at my desk. I'm glad to get my son started out on the right foot with an excellent model (the 35S). If you're looking for a strong calculator that has a keyboard that means business, this is the one.
  
  BTW, the instruction book is pretty good, too.
  
  
• finally, it even looks like an engineer's calculator!!
  By A1XNS1XO13JLTV on 2007-12-04
  i bought a hp33s during my last year in college since they banned all graphing calculators due to the memory, programs and text storage capabilities. i liked the 33s but the color and shape was weird. i bought the 35s about 3 months ago and i love it. the keyboard is better, the enter key is in the right place (even though i never owned any of the old hp calculators)and actually felt good. the manual (like the 33s) is good and covers a lot of useful things (too bad the 50g manual/s suck). i'm using my 35s for graduate EE studies and i love it. i do prefer the 33s leather case to the 35s zipper case and since i had both i keep my 35s in the leather slip case. i'm taking the FE exam next year and of course this calculator is coming with me. i even bought one for a christmas gift for the guy that introduced me to HP and RPN back when we were both in physics I (wow, a long time ago...).
  
  keep it up HP. you guys have a long way to go to get back into the engineering classrooms but with the 50g and the 35s (recently approved for the FE/EIT exam!) you're getting back into the fight, finally. RPN rules!
  
  
• Don't waste your money!!!!
  By A3ISYTPC1R5MXZ on 2008-02-27
  
  It is a shame that HP has released such a ergonomically poor design, although the calculator has the look and feel of the older classic calculators; that is about the only thing you get for your money. The functionality of this calculator can be described as confusing and very poorly thought out, it is hard to believe that HP has released this model with its present flaws. As an example; simple things like numerical base conversions which should be a straight forward function using a few key strokes, will leave you wondering. However, when you try such conversion in this calculator it will leave you scratching your head for an answer and don't bother looking for the answer in the user's manual, because the so called "user's manual" has very little information about anything and it is pretty much useless.
  
  
  

• HP 50g Graphing Calculator (F2229AA#ABA)
• FE Review Manual: Rapid Preparation for the General Fundamentals of Engineering Exam (F E Review Manual), 2nd ed.
• HP 33S Scientific Calculator (F2216A)
• HP 12C Platinum Financial Calculator
• FE/EIT Sample Examinations, 2nd Edition