HP 20S Scientific Calculator

There is a lot to be said for INTEGRITY, and these guys Got It.Totally professional. I love it! Just like the old days. I was born in the early 60s, and I remember when people said what they meant, and stood by their word. That's these guys. ( But with a sense of humor also ).Wonderfully packaged, everything transparent and guaranteed in writing, and my new / used calculator that I have been using for years in linear accelerator labs is still available for me, simple and good.What can I say. I am very happy for their product guarantee also.So buy from these guys, and you will have rainbows in your life thereafter.

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 not running HP os standard

I bought this calculator in 1989 while getting my engineering degree. Since then it has gone everywhere with me, through thick and thin. Nothing else was as convenient or had all the functions I needed without the useless frills. The buttons were hard, not rubber, and positively engaged when pressed. I used this in -40 F environmental chambers and then went straight into 100 F and 95% humidity test chambers, it never missed a beat. It endured exposure to large electrodynamic shakers in the test lab which scrambled computer monitors from 10 feet away. It has been baked, frozen, bombarded with electromagnetic fields and dropped on concrete floors more than once but never failed to perform. Mine was made in Singapore although I see newer models were made in Malaysia.Sadly in early 2015 it went missing. I have torn through everything I own and been unable to locate it. I also am unable to find something as simple, complete, and durable looking as this wonderful tool.

I first owned a HP 20S in college back in the early 1980's. A couple of years ago, much to my dismay, it stopped working. It was great finding another one. It works great!

The last decent calculator made by HP. Why do I say that? There is nothing unique about HP calculators compared to other brands in the basic way they work other than RPN notation if you are into that sort of thing. What was truly unique about pre 1990s HP calculators was button feel - a little tactile click that let you know that the button was depressed without having to look at the screen. This really speeds up any calculator operations. Compare to typical casio and TI calculators with very mushy button feel that you definitely have to look to make certain the button was depressed. After this generation of calculators, HP started making mushy button calculators like everybody else. I already had two of these and wanted a backup. If you want a basic scientific calculator with crisp buttons, this is it. There isn't any other.

I've had this over 20 years. I use it monthly to balance my checkbook and weekly to ensure my paystub is correct. The buttons, and the unit overall, is very durable. Old school quality I guess. The batteries last a long time, I'm not sure if I've ever replaced them. It has unit conversions which I have found handy sometimes. It lacks RPN, but I'm not an engineer or physicist and haven't missed it.I actually bought two of these; I got the second because I lost the first. The first had a nicer case. Both had a soft slide-on case, but the first was like a vinyl/fabric case with the edges sewn and the seam turned inside, while the second was just vinyl, with the edges just heat sealed together, i.e. cheap.

I acquired a HP-20S in the late 1980's, used it as an engineering aide until the keyboard failed a couple or years ago. As it was discontinued at that time I acquired a sucession of calculators hoping to find something similar, but found either overly simplistic or near uselessly complex affairs. I only recently I discovered that used 20S's were available and have so purchased one. The main reason that I like the 20S is that the fairly simple programming system gives it enormous capability. It's actually an astonishing peanut sized computer with subroutines, comparative statements, and so on. As with programing any computer it helps to write an outline of the major steps and by so doing you know what information is needed and how to quickly enter it - all without having to memorize the awkward operation of a limited selection of internal routines