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The Hewlett Packard Calculator Page

Hewlett Packard Calc

(since April 22, 1997)

Last Update: August 31, 2021 -- THE HP REFERENCE




HP Poster
(click here for a larger view)


After 7 year from the publication of the original HP Calculator poster and over 1 year in the making, I am proud to introduce the Calculators of HP Poster #2 for all HP fans. This poster shows every HP calculator made starting with the famous HP-35. It now includes pictures of 115 HP calculators and 20 perpherals made through 2012.

Each calculator is displayed with it's production start and end date, and the project codename. Lots of new information has been added including dates and code names for more of the HP41 accessories, HP-IL devices and printers.

Also new for this version is the inclusion of calculator entry modes (RPN/Algebraic/CAS/BASIC) and I/O capability (IR, Serial, StreamSmart, HP-IL, USB).

And every calculator on this new poster has been rephotographed with an active display!

HP Poster

The HP Calculator poster is very suitable for framing with 1/2 boarders and will make a wonderful gift to any HP enthusiast.

The poster is printed using a state-of-the-art stochastic screen process on heavy 100# Gloss Cover paper with a aqueous coating. The The Stochastic printing process, also called frequency modulation (FM) screening, uses small (10, 20 or 25 Micron), same size dots in a random pattern and varies the density of the dot to create an image that is closer to continuous tone. You actually can't see the pixels on this new poster without a magnifying glass!

The poster measures 18" (45.7cm) in width and 24" (61cm) in height. The poster will be shipped in a rugged 3" x 18" Kraft Mailing tube.

It is an essential element in any HP calculator collection.

Buyer Feedback!

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  • Smooth transaction, quality item, rapid shipment, great communication! A+eBayer!
  • GREAT, thanks for the poster ! Extremely POSITIVE
  • Thank you for the great HP poster!
  • Perfect and ultra fast shipping. Very fine article. AAA+++
  • Very Nice Poster- Thank You!
  • Excellent poster! Sent quickly in quality packaging. Smooth transaction.
  • Very good quality poster, great service & communication, fast delivery: PERFECT!
  • Excellent poster arrived safely today. THANKS.
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  • Super Poster! Sehr freundlich! Alles Bestens! Thank you! +++AAA+++
  • Excellent poster. Quick shipping in well protected tube


The HP 12c Platinum is a powerful tool capable of handling the most complex and detailed financial calculations. Users of the HP 12c Platinum will enjoy the flexibility this calculator offers with both RPN and algebraic modes of entry, the increased memory capacity and the more-than 130 built-in functions. Easily calculate loan payments, interest rates and conversions, standard deviation, percent, TVM, NPV, IRR, cash flows, bonds and more. Ideal for real estate, finance, accounting, economics and business work. Permitted for use on the CFP and CFA Certification Exams, and GARP FRM Exam.

The Platinum is the first of HP designs to include both modes: ALG (Algebraic) and RPN (Reverse Polish Notation)! Notice the mode selections above the "CHS" and "EEX" keys.
Now if HP would come out with a hybrid of the HP15C and the HP32SII!. Here is a mockup I created in November 2002. Note the "+" key where I envisioned the dual mode capability (click on the pic for a large view). Needless to say I thought RPN was dead when HP discontinued one of my favorite machines, the HP32SII. Then I saw the announcement today (June 2003) of the HP12C Platinum with it's dual Algebraic/RPN modes. Maybe a scientific RPN machine is in the future yet! I don't need a boat anchor [graphing] scientific, I need a good scientific with the convenient foot print of the 12c/15C (Voyager) family that runs RPN. Throw in the dual Algebraic/RPN modes and you've got a win-win solution for both camps!

The HP-33s 2-line display scientific calculator is the long awaited replacement for the HP 32sII RPN Scientific Calculator.

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

Accuracy, functionality, dependability. Scientific projects require these vital attributes for success. The pocket-sized HP-33s scientific programmable calculator delivers them - and more - with features that include 31KB user memory, your choice of RPN and algebraic data-entry modes, a powerful two-line display, and the timesaving HP Solve application. Permitted for use on SAT I, SAT II Math IC/IIC, ACT, PSAT/NMSQT, AP Chemistry/Physics, PLAN, EXPLORE.

Where's the "Enter" key??? Gee this calc must have been designed by somebody with an Algebraic mind...

HP fans can breathe a shy of releif. The handheld RPN calculator is not dead. The 33s is a reincarnation of the popular and near perfect 32sII calculator.

o Retains the functionality of the 33sII calculator.
o 2 line alpha-numeric 5x7 dot matrix display.
o RPN and Algebraic modes of operation.
o Excellent manual.
o An eye catching design (too bad engineeres don't care).
o 32k of memory (the 32sII had 384 bytes!).
o Built in physical constants.
o Quotient and Remainder of Division.
o Nice leather case (it's a little too thick).

o Not in the footprint of the Voyager series (11c,12c,15c).
o Tiny enter key.
o Horrible shift key colors that you can't distinguish between in normal light.
o Comma and decimal points need to be larger.
o Funky slanted keyboard... actually this is not so bad once you get used to it.
o No logical operations (XOR, AND, etc)... build in some of the 16c functionality.
o Sub-menu functions that you never need are moved to top keyboard level (32sII - PARTS and PROB menus).
o Only 26 labels for 32k of memory.

Summary, it's a step down from the 32sII but RPN is still alive. The calculator will be popular and seems to be hopping off the college bookstore shelves. Now HP, repackage it in the Voyager series format!!!

Most web sites are posting this picture. Notice the change in the keyboard layout????

OK, one more try. Take the great display on the new 33s (with larger comma/decimals), and merge it into to HP-15C package. That's an engineers dream calculator.

This is the 35th anniversary tribute to the HP-35... A big improvement over the crazy HP-33s!

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
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
AP Chemistry/Physics
PALO ALTO, Calif., July 12, 2007

HP today unveiled the retro HP 35s Scientific Calculator in commemoration of the original HP-35, the world's first handheld scientific calculator launched 35 years ago.

As part of its year-long 35th anniversary celebration of the company's entry in the handheld calculator business, HP also named the winners of its nationwide calculator video contest.

The HP 35s pays tribute to its revered lineage with a classic design that is reminiscent of the original HP-35, including protective raised edges so that the calculator rests nicely in the palm of one's hand.

The new calculator is also HP's most advanced scientific programmable calculator, featuring ample memory for keystroke programming, equation solving and more than 800 storage registers; 100 built-in functions; and a large, two-line display with adjustable contrast to easily view entries.

For greater flexibility, the HP 35s allows users to easily switch between Reverse Polish Notation (RPN), HP's exclusive time-saving input mode, and the traditional algebraic mode. In addition, the HP 35s comes with a premium zippered protective pouch.

"With the HP 35s, HP honors the legendary HP-35 scientific calculator, which revolutionized the way engineers and scientists worked and marked the birth of HP's innovative heritage in the handheld calculator market," said Sam Kim, acting general manager, Calculator Division, Personal Systems Group, HP. And today's winning contest videos help share this HP story, showing the new online generation how HP calculators touch people's lives.

HP 15c

Bring back the HP-15C

Why isn't the 15C still being made? Unlike the 12C, the 15C was designed for scientists and engineers who, when it comes to calculators, are all about the newest and fastest. As faster and more powerful calculators were designed and built, the 15C slowly moved into history. During this time period calculators were a much more important tool for scientists and engineers than they are today. For complex calculations, an HP calculator was often the only, if not the first, choice of many engineers. Today desktop computers are ubiquitous. For complex calculations a personal computer is the tool of choice for most people. Outside of college exams, today the calculator is mostly used for less complex calculations when you are away from a computer. Which is why I think the HP 15C should be brought back. My 15C was with me everywhere I went. If I had a need to do a calculation, my 15C was always handy. Today all I have is a 48GX and a 49G, I rarely take one of them with me when I go somewhere because they are just too big. For the vast majority of the calculations I find myself doing on a calculator, the 15C is more than adequate.
by Chris W
HP First

The First and the Last HPs

These are the First HPs I collected and these are the Last HPs I need to complete my collection. If you should have a duplicate, be assured I could make a fine home for it.

A Guide to HP Handheld Calculators and Computers


A Guide to HP Handheld Calculators and Computers by W.A.C. Mier-Jedrzejowicz, Ph.D., 5th edition, 978-1-888840-40-7.

o Updated from last revision in 2003.
o 224 Pages (40+ more than previous edition).
o 12 full color pages of HP calculators (2 more added from previous edition).
o Spiral binding for easy page folding.
o Updated to the HP 10s with a photo of the new HP 17bII+.

"The definitive guide for collectors of HP calculators." - Guy Ball.

"This is a must have for any HP calculator collector." - Rick Furr.

Collectors, and anyone interested in Hewlett-Packard handhelds, will find this a useful and fascinating guide. Starting with the HP-35, all calculators, computers and the HP-01 watch, are listed and described. A set of colour photographs complements the text and underlines developments from the early models to the present range.

Available from:
HP 11c

A look inside Hewlett-Packard's HP-11C

A look inside Hewlett-Packard's HP-11C is an article on the development of the HP-11 from "Electronic Packaging and Production", March 1982. "Hewlett-Packard engineers have employed the latest packaging technology in designing the HP-11C, a programmable calculator with an extensive set of built-in scientific and engineering functions."
HP 95lx


HP-95 PALMTOP: POWER IN A SMALL PACKAGE is an article on the development of the HP-95 from "Design News", July 08, 1991. "Two technology giants team up on an innovative computer that is 'unconsciously portable'."
HP Microcode

Microcode: Electronic Building Blocks For Calculators

Microcode: Electronic Building Blocks For Calculators is an article from Hewlett Packard Personal Calculator Digest, Vol. 3, 1977. "Just as DNA can be called the building blocks of the human organism. Microcode can be called the building blocks of the electronic calculator."
HP Cochran

Made in USA...finally!

Made in USA...finally! is an article on the development of the HP-35 from the "THE ELECTRONIC ENGINEER", March 1972. "An inexpensive, pocket-sized machine revolutionizes calculator design, and we did it right here."
Hewlett Packard Publications

The HPs

This page contains the following tables:
HP Date

Hewlett Packard Dates

Hewlett Packard Dates is a table of ALL of the HP calculators made. For each calculator model within this table are Availability, Code Name, Introduction Date, Discontinued Date, Collectors Value, Introduction Cost, Final Cost. Also each family Size, Weight, and Code Name are shown.
HP Scale

Hewlett Packard Weights

Hewlett Packard Weights is a table of ALL of the HP calculators with their code names, weights and dimensions.
HP 30comp

30 Series Derivations

30 Series Derivations -- The Classic series aren't the only series that HP made design changes to. The 30 series has some of the most major of them all.

The first generation of the 30 series used a highly experimental construction technique. HP actually used a flex circuit board and held the ICs against the circuit by clamping a plastic form onto a foam backed steel plate without solder. The steel plate was used to stiffen the case. The flex circuit also wrapped around to the front where keyswitch domes were formed to replace the older metal dome (or plate) keys.

As the parts and housing aged the ICs became intermittent and the calcs had to be serviced. HP addressed this design flaw in later models by changing to a conventional printed circuit board (PCB) with ICs soldered to it and removed the steel plate. The keys were switched back to metal domes. The resulting changes fixed the intermittences and the calculators were 1 1/2 ounces lighter (from 174 grams to 130 grams).

How do you tell the difference? The 30 series are quite hard to open due to a locking plastic edge on the bottom. The give away is the plastic domes are mushier with a longer travel. The metal domes have a short travel with a distinct click. Also the metal dome units are lighter (~130 vs ~174 grams).

I see two types of series derivatives that seem unrelated, the metal vs dome keyboard designs and the different keyboards colors.

If you don't mind, check your collection and help me fill in my matrix some more.
Hewlett Packard Publications This page lists the following:
  • All of the HP Journal Issues that had an article on HP calculators. Each article is listed with it's author, page number and a short description.
  • Also listed are the HP Digests with their articles and calculators covered in each.
  • Finally, the HP Key Notes and HP 65 Key Notes are listed by the number in each volume. I have never been able to locate any Key Notes Issues so I can't tell you what is in them.
    If somebody wants to send me an ASCII text file of the contents, I'll include that.

Hewlett Packard Articles

The Hewlett Packard Articles page contains a series of articles written by Wlodek Mier-Jedrzejowicz. They were published in DATAFILE, the jounal of the HPCC (please join!).

If you like this material then you have to buy his book:
A Guide to HP Handheld Calculators and Computers
HP Code

Codenames of HP Handheld Calculators and PDAs:
Facts and Speculations

Codenames of HP Handheld Calculators and PDAs: Facts and Speculations by M.J.P. Staps, published in Europe by the POCKET foundation. ISBN 90-802939-1-1. Softcover, 64 pages, with 14 color photos.

"Any serious collector of HP handhelds would find this a fascinating book."*-Wlodek Mier-Jedrzejowicz, author of "A Guide to HP Handheld Calculators and Computers"-

This 59 page book discusses the codenames given by Hewlett-Packard to the families or series of HP handheld calculators and PDAs. This includes codenames given to individual members of a family or series. Other information includes explanations and speculations on model numbers and used processors.

The book also mentions other details on things like the backside of HP handhelds, introduction dates, numerology, manuals and colours. The book is supplemented by 14 high quality color photographs including one of a prototype of the OmniGo 700. This book can be regarded as an excellent companion to Wlodek Mier-Jedrzejowiczs book "A Guide to HP Handheld Calculators and Computers".

*Extract from a review made by Wlodek Mier-Jedrzejowicz in Datafile V13N3, the English journal for users of HP handhelds. Other extracts from this review:

"He includes several photographs of the HP OmniGo 100 PDA, and the HP OmniGo 700 - I found these very interesting - and I compliment him on the quality of the photographs."..."Some of the speculation regarding codenames is very clever and one can learn some history and science from it, quite apart from learning about the HP handhelds themselves."

Contact the author Marc Staps - marc.staps (at) for purchase information.

The Calculator Reference by Rick Furr (
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