Customer Reviews

HP HP20S Scientific Calculator

5 star:		(12)
4 star:		(3)
3 star:		(0)
2 star:		(0)
1 star:		(0)

 

 

This is, quite simply, the best algebraic-notation calculator short of the graphical types. How is it superior? Let me count the ways:

1. It has a 12-digit display, but it's not limited to 12 digits. If it needs more display room, it will scroll.

2. It uses commas for thousands separators.

3. It has the easiest-to-use percentage calculations I've ever used.

4. The display shows "PEND" when you've hit an operator key (+, -, etc.) and it's waiting for the operand. This is great when you're doing involved calculations interspersed with thinking or looking info up. With other calculators, you come back from your diversion and have to think about whether you hit the operator key yet or not. Worse, some calculators change their behavior if you hit an operator key more than once, so you can't hit the operator key again without consequences.

5. It's built really well, and the keys have a nice tactile feedback.

6. There are several other nice features, but I'm running out of space. Suffice it to say, whoever designed this calculator knew how to make it pleasant to use as well as functional. Most other calculators are either too simple to be useful or too complicated to be useful. The HP20S strikes the right balance for me. I have two now and would buy a 3rd in a heartbeat if I could find one, just to have a spare, just in case.

This calculator is a cousin of the 10B finacial calculator (now discontinued). It's a good calculator with good button feel and a lot of preprogrammed functions including stats. However, the newer models have the keys and faceplate markings written in new colors that are hard to see. The picture on this page is of the old version of the calculator. The colors on the new ones make the calculator much harder to use in my opinion. They seem to get lost on the brown background.

I bought my first HP 20S in 1988 when I started college. That one last about 8 years and then I bought another in 1996 which I am now replacing. These calculators are amazing. I work in a lab, and in the course of using them I have dropped them and spilled chemicals on them numerous times (they keys flooded but the calculator worked fine once it dried out), and through it all they keep on working. THe first calculator i replaced because they keys wore out, this last one finally got hit with a chemical solution it couldnt' handle. The 20S is very easy to use in an ergonomic sense because of the unique spacing of the keys. The way the calculator works in terms of which keys do what is very straightforward. The programmable nature is wonderful if you are doing repeated calculations. I wanted something that was a bit more advanced than the TI-35 I used in junior high school, but not something so complicated that i would never figure out to use it. This calculator fits the bill perfectly. I'm now buying my third HP 20S in the last 12 years, and I can't recommend it enough.

I purchased my HP 20S about six years ago and have had no problems. The best features are the keys, key layout and physical durability. The keys are a hard plastic and have an angled profile which makes the calculator easy to use when wearing protective gloves. The key layout is very useful for quick statistical entry and calculations. The durability of this calculator is amazing. It has been through more than I would like to admit, and still functions perfectly. I prefer algebraic entry over RPN and would recommend this calculator to anyone considering a top-notch non-RPN scientific calculator for heavy laboratory use.

OK. I've used my current 20S for years. As a programmer, I can get most of what I want from the computer itself. But for things like HEX->DEC, DEC->HEX, etc conversions, this one has been great. When I first bought it, I was not too happy about not having RPN. However, when my wife wanted to do some calculations, the non-RPNness was perfect for her. It's been great for those incidental computations. Here's where it looses stars. About 5 months ago, the batteries died. I bought new ones at Radio Shack (possibly part of the problem...) and it worked great.. for about a month. I bought another set, it got me another month. It was at that point, I thought I'd find a better calculator. I tried to order the 32ii but I got too impatient for the 1-2 week wait that quickly doubled. I'm getting my second 20S now. It's just what I want.

I've owned my HP 20S for 33 years. If I'm not mistaken, I believe I paid less than $20 for it at the time, so I'm rather shocked at how much they're going for today (if you can find one, that is, as HP discontinued the model in 2002 from what I've read). Not often when something appreciates in value like that, especially a calculator!

Obviously this calculator doesn't have all the bells & whistles that many modern calculators do (graphing, multi-line display, etc), but make no mistake... this baby got me through college (a Math major, BTW) and beyond! And unlike the, say, TI-84, this puppy really is a "pocket" calculator that is easy to carry in a shirt pocket or stow efficiently in a confined space (e.g. briefcase).

The batteries last a surprisingly long time, but boy are they expensive to change when they go (almost as much as I originally paid for the calculator); but considering the price of a new calculator, maybe it's not so bad after all. :-)

Like I said, I've owned (and used!) mine for 33 years, so it'll last awhile and is a handy little gadget to have.

Rugged construction, comfortable keys.
Lightweight, handy, thrifty with batteries.
Businesslike appearance of quality, unlike the el cheapo plastic offerings by TI and the latest HP models. They just don't build them like this anymore!

My only real complaint about the keyboard layout is the fact that, to enter a power-of-ten exponent (EE function), one must press two keys: the blue-shift key and then E. A little annoying if you use alot of numbers in scientific or engineering notation.

A dependable basic scientific calculator for those who choose to eschew RPN and don't require graphing. With "only" ten memories and 99 programming steps available, might be a little cramped for those with big applications in mind. But for 90% of one's mobile computational needs it fits the bill.

The calc's "programming" capability actually functions as a macro recorder would in a computer application program. You enter programming mode and press the keys needed to perform your computations, which are recorded into memory. Then you exit programming mode and can view/edit the keystrokes that comprise the program. The keys are represented by codes corresponding to the key positions in the hardware keyboard matrix. There are no "keywords" or "statements" as used in computer programming languages, just one- two- and three- character numeric codes that represent the calculator key's physical location in the keyboard matrix. There is a picture in the manual showing how to decipher the codes, but it's just as simple to describe: the keycode's first digit is the row number (1-7) and the second digit is the column number (1-7). The only complication is that the double-wide INPUT key occupies two column positions. Despite the primitive nature of this scheme, some conventional programming language features are available, such as 1) subroutines 2) testing of values and branching to a specified line label [16 allowed, 1-9 and A-F] 3) suspension of program execution to allow for dynamic manual input by the user.

The user may manually load values into any of the 10 available memories before execution, and the program may be coded to fetch and store these as needed. Multiple programs may reside in the calculator's memory simultaneously, and be executed selectively by specifying the starting line label to begin execution. Since only 99 program steps are permitted, only two or perhaps three complicated programs will fit in the calculator; however, they can share common subroutines. Since this calculator lacks any means of getting information into or out of it (no USB or any other data ports), if you need to keep available more program code than can fit your only option is to get out a paper notebook and record the program's codes by hand in pencil or ink! Then you'll have to make room for the program by deleting something, and key it all in by hand! Or use the method I do: acquire another HP20S!

The lack of alphabetic string constants and variables means that to make meaning of the values produced and input into the program, the user will need to carefully record meaningful text labels to be associated with these -- meaning, keeping program notes on paper or a Palm Pilot. For really complex mobile programming needs this calculator will be frustrating to use, and the use of a real programming language or a spreadsheet on a handheld computer would be a more effective solution. Consider the HP20S as suitable only for sophisticated math problems requiring a minimum of prompts for input values and text labels for output values. The HP20S is handy for calculating frequently-used formulae for which you instinctively know the required input and output values. I keep mine on hand for making independent verification of the accuracy of spreadsheet formulae (I am very distrustful of computer code not written by myself). With this calc the only things you can put in or get out are numbers, though in hexadecimal you might be able to do some things with the hex digits A - F, but this seems kind of funky for regular use. One that comes to mind is to use as a sort of "prompt" to alert you that your program has halted to allow you to input a value into the display -- effective since hex numbers appear in the display right-justified. Unless you happen to know from frequent use of your program, there is no other way to tell if the program has halted because it reached its end, or is temporarily halted for input.

There is no built-in looping mechanism, but using the value-test keys and the GOTO key, one could be devised if one reserves a storage register for use as the loop index. It is possible in many instances to save a keystroke or two (a program line or two) if one pays close attention in the manual to some of the finer points of formula building, particularly storage register arithmetic (no need to fetch to display first), chain calculations (no = key needed), the LAST register, and the fact that the closing parenthesis is not needed for nested operators. There are a couple of quirks in the programming language -- see the Wikipedia article for details. To make the most of the programming mode, and the other advanced features, you definitely WILL need the 20S manual. Calculator Source lists a PDF or paper book for $30; the other place on the web, [...] is free but delivers the manual for the 30S instead, NOT the 20S! User beware.

Six libraries of advanced math programming are resident in ROM, and these may be copied to RAM for customization by the user. The six are: root finder, integral calculator, complex math, 3x3 matrices, quadratic equation solver, and curve fitting.

I got my first HP20S from Walmart back in 1997 for 20-some dollars! Try to find one these days for that little. Had I known they would've appreciated so much, I would have scarfed up a whole carton of them. But who'd have thunk of a consumer electronic product that actually appreciates in value ???

Here's a little tip for avoiding drained batteries. If one slides the calc into its slipcover the usual way, LCD first, then it is possible to inadvertantly touch the ON button and not realize having done so, since the LCD is not visible inside the slipcover. I have lost two sets of batteries this way; so one must be extra careful about keeping fingers away from the corner where the ON button resides (lower left).

I know a better way. Slide the calc into the slipcover BACKWARDS, so you can keep an eye on the LCD and make certain the calc stays powered down. Also, since you are forcing the calc in by its top edge, it becomes nearly impossible to inadvertantly touch the ON key. No more dead batteries!

I have had this beast for over 20 years. It has been through countless batteries and never failed. I could never count how many times I thought it would surely be destroyed from physical abuse... Yet, it still works great. Stephen King should write a book about this calculator.

Let's face it! If you are going to do a complex calculation, you are going to break out your PC and use MATLAB (insert your own favorite mathware here) where you can A) do the calculation right and B) not have a take a coffee break while your graphical calculator thinks.

But so many times a day there is that quick calculation you need to run. What you need is a basic scientific calculator that can handle any of those run of the mill number crunches.

I got my first HP20S as a science fair award when I was in High School and I used it for this purpose all the way to finishing my Masters in Engineering. I left my calculator behind in the lab when I graduated because I stupidly had used it for months wearing epoxy sticky latex gloves (the calculator worked fine, but who wants to use a sticky calculator). I have small hands and I was able to hold this calculator in one hand and make all necessary computation using only a thumb. This is a feature I sorely miss! Also, the keys would go "klick-it" when you depressed them so that you had very nice tactile feedback.

One caveat, I can only speak to the calculator in the image above, and not to any changes that may have been made. Mine was originally purchased in the early 1990's! But boy I miss it!

I have simply fallen in love with this one. There are just very few things that one can say are wrong with this calculator. In fact, i am really having to stretch my memory to find some faults in it.

Someone dropped a cup a boiling tea over it just before one of my major exams. It worked then, and is still working just fine. I love the feel of the keys, since they arent as feeble and non existent as the ones in some of the other ones. It gives you a solid rugged look.

Once you get used to this one, it is going to be very hard for you to switch to anything else. Trust me on this!