HP 35s Scientific Calculator


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UPC: 883585142859   Part: F2215AA#ABA


  • Get professional performance from HP’s ultimate RPN scientific programmable calculator—ideal for engineers, surveyors, college students, scientists and medical professionals. Scientific projects require accuracy, functionality and dependability for success. The HP 35s scientific programmable calculator delivers them—and more—with features that include 30KB user memory, your choice of RPN and algebraic entry-system logic, a convenient two-line display, and the time-saving HP Solve application.



  • RPN or algebraic entry-system logic, keystroke programming, HP Solve and 100 built-in functions, Large 2-line display with adjustable contrast, Single and two-variable statistics, linear regression and more, 30 KB of memory plus 800+ independent storage registers, Fraction mode plus fraction-to-decimal conversion, 42 built-in physical constants, plus a complete library of unit conversions, inverse functions, cube root, logarithms, exponents, factorials and more

Ideal for

  • Ideal for engineers, surveyors, college students, scientists and medical professionals.

Permitted for use on

  • Permitted for use on SAT Reasoning Test, SAT Subject Tests in Mathematics Level 1 and Level 2, ACT Mathematics Test, PSAT/NMSQT, AP Chemistry/Physics, PLAN, and EXPLORE.

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Internal specs

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Best used for

  • Engineering; Surveying; Science; Medicine

Permission usage

  • SAT Reasoning Test; SAT Subject Tests in Mathematics Level 1 and Level 2; ACT; PSAT/NMSQT; AP Chemistry/Physics; PLAN; EXPLORE

Built-in functions

  • Over 100

Memory registers

  • 800

Memory, standard

  • 30 KB


  • 2 x CR2032 batteries; battery life: 0.73 year @ 1 hr/day (approximately 9 months)

Power off memory protection

  • Yes

Auto power off

  • 10 minutes

External specs

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  • Adjustable contrast with 2 lines x 14 characters + indicators, 14 character dot matrix (5 x 7)

Display type

  • LCD

Dimensions (W x D x H)

  • 8.2 x 1.82 x 15.8 cm

  • 3.23 x 0.72 x 6.22 in


  • 125 g

  • 1 year warranty (may vary by region)

What's in the box

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  • Calculator, batteries, user manual, premium protective case

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Customer ratings and reviews for HP 35s Scientific Calculator

Rated 1 out of 5 by Misses keystrokes, tan gives bad results I got this calculator because of its large number of features and RPN mode, which I use exclusively. On initial inspection it appears to be great; it's visually attractive, easy to read, and the keys feel good. Unfortunately, it didn't take too long for me to realize that, at least in RPN mode, the calculator consistently misses keystrokes. Keying in 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 rarely gives the correct answer (45). Additionally, I found that the tan function gives slightly incorrect answers at values very close to 90 degrees. Try taking the tan of 90.0000001 and comparing the result you get to what your computer tells you. The tan error is a minor issue for me, but the missed keystrokes makes this calculator unusable. March 17, 2010
Rated 5 out of 5 by A Classic RPN Calculator I grew up on RPN HP calculators. It's nice to see that HP sitll makes good RPN cacluators. I would strongly recommend the 35S to anyone that prefers RPN-style calculators. By the way, if you're trying to decide whether to buy a '33S or the 35S and you like RPN...buy the 35S. It's no contest! The RPN capability of the 33S is somewhat compromised. The 33s is a fine calculator but it's a better algebraic calculator. The only thing I wish the 35S had was a way to plug-in modules or download programs via USB. What would be fantastic would be to plug in USB memory sticks for storage of programs and data storage. If HP is listening...this feature is worth $20-30. February 17, 2010
Rated 5 out of 5 by HP 35S - An Instant Favorite Pros: I was enamored by the classic look, including the return of the legendary double-wide ENTER key, so I bought my HP 35S a year ago. Keyboard feel is classic and excellent. If you are used to the keys of the old HP 25, 45, etc, these have a little less travel and spring pressure is lighter. The two line display is clear and easy to read (although the numbers are a bit grainy for my tastes). This is a very powerful, programmable calculator and is a very comfortable "daily driver" for trig, log, and algebraic calculations in RPN mode (haven't tried Algebraic mode). There is honestly nothing equivalent to it in the market. I am planning on buying a second one for home use. Cons: If you do a lot with complex numbers or base conversions, you will be frustrated with this calculator. Keyboard operations such as square root, reciprocal, etc should seamlessly handle complex arguments, but they return errors instead. You have to read the manual to navigate through the complex number calculations. Base conversions are clumsy, and you must memorize which keys represent A-F, because it's NOT the keys that are marked A-F! That was a particularly disagreeable design decision, in my opinion. Yes, the calculator will do all these calculations, but you have to become adept at it, which to me represents flawed design. Some have complained about the lack of a polar/rect key, which is a valid complaint, but this machine will do the conversions. You just have to re-tune your brain to where you view your problem in terms of vectors. To be fair, every other function I have worked with on this calculator works excellent. It's simply a FUN calculator to use and program, and I would highly recommend it to anyone, even those doing complex numbers and base conversions. February 3, 2010
Rated 5 out of 5 by Best HP Scientific Calculator Ever Before purchasing my HP35s calculator I did a fair amount of reviewing the comments and reviews from other users. The comments I saw consisted primarily of praise (particularly when compared to the calculators of other manufacturers and even some previous HP scientific calculators, specifically the HP33s). Clearly RPN makes any HP calculator easier and more flexible to use, and the HP33s was a step backwards from the HP32sII in terms of the physical and mechanical design. The most common complaint was the lack of function keys for 'rect to polar' and 'polar to rect' conversions. The HP35s is the best calculator I have ever used regarding any type of 'rect', 'polar', or 'vector' operations. The calculator does not have 'rect<->polar' keys because they are not needed! They are as unnecessary as keys for converting between the 'fixed', 'scientific' or 'exponential' modes for displaying numbers. 'Polar' and 'Rect' are just different ways of viewing a vector, whether it is a 'vector' or a number with 'imaginary' components. What makes the HP35s calculator so powerful is that 'vectors' or 'imaginary' numbers fit into any register or memory location. The HP33s and HP32sII need to use both the 'X' and the 'Y' stack registers to do 'vector' or 'rect/polar' arithmetic/conversions, and therefore would then require the use of a program to be written for the calculator to be able do any arithmetic on the 'vector' or 'rect' coordinates. PRO: If you want your results to be displayed in 'polar' coordinates, set the display to 'polar'. Any 'vector' or 'rect' conversions or arithmetic can be entered in either 'rect' format ( x i y) or 'polar' format ( r O a), are converted automatically, and can use the same 'operators' ('+','-','*','/') to add, subtract, multiply, or divide the vectors by 'constants' or to do 'vector' arithmetic. As far as I know, to do any type of vector arithmetic on any competitors calculator, or previous HP scientific calculators, required the use of a program written for the calculator. Additionally, the HP35s directly supports both two dimensional and three dimensional vectors/matrices, without requiring the use of any programs to be written. CON: I was expecting the HP35s to be faster than the previous generation (ex: HP33s). I have been using the calculator a few hours each day for roughly one week now, and have yet to be disappointed. January 17, 2010
Rated 5 out of 5 by HP35s: A new beginning for HP calculators I put the HP35s through the famous voidware torture tests: Their test package is divided into 4 parts, some tests of which are discussed further below: a) trig accuracy b) powers and roots tests c) Lengthy integrations like ln(cos(x)) from 0 to 1, etc. d) calculation domain of trig functions, etc. I must say that that the HP 35s did extremely well (in both speed and accuracy) when compared against some 2 dozen other calculators. I also did further testing of the complex number capabilities in both RPN and in the Algebraic (or EOS-equation operating system) mode. 1) Setting up in standard RPN mode (without using any parentheses of course): A) (27*i^2)^0.333 = -3.0 and (32*i^2)^0.60 = -8.0 worked fine as expected, with only real solutions listed (see also below) but: B) (-27)^0.333 cannot be evaluated in RPN at all and it gives an error as INVALID DATA with the same occuring for (-32)^0.60 or when using the square root key (SQRT). 2) Setting up using parentheses in standard ALG mode: A) (-27)^(1/3) = -3.0 and (-32)^(0.60) = -8.0 again as expected, but using: B) (27*i^2)^(1/3) only yields a numeric answer (symbolic answers are not available on this machine) that is completely correct, but is one that has both real and imaginary parts (the same is also true for an evaluation of (32*i^2)^(0.60) as well). C) Finally if you perform (i^2)^0.50, it gives the correct answer = i as expected, but quite ironically: (-1)^0.50 = -1.0 (using the y^x key) and similarly, (-100)^0.50 = -10.0, both with only Real roots with no imaginary part to the indicated solution whatsoever!!!!!!!!!!!!!!!!!! Incidentally, the standard square root key operating on -1 or SQRT(-1) yields SQR(NEG) as an error condition and SQRT(i^2) yields INVALID DATA as an error condition. USER BEWARE: So it seems that the linkage in this machine in ALG mode across real and imaginary parts of complex numbers is not complete in its most general sense as the simplest of simple evaluations on the ALG side of the machine is NOT correct. Unfortunately the HP35s also does not have either a RE{} or an IM{} set of keys to check any of this even further! It will also as expected give an error for an evaluation of SQRT(-1) for the RPN side of the otherwise very terrific new HP machine (directly using the square root key). January 12, 2010
Rated 4 out of 5 by Converting from Binary to Decimal does not work. Converting from decimal to binary works OK, but starting from binary and converting to decimal does not work. January 4, 2010

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Owner support

Warranty information

This product is covered by the standard HP warranty

Support information

Support for this product is provided by HP Customer Care

Returns & exchange information

The HP Home & Home Office Store will accept returns or exchanges for this product up to 21 days after delivery

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