The Museum of HP Calculators displays and describes older Hewlett-Packard calculators. There are also sections on calculating machines and slide rules as well as sections for buying and …

HP-11C The HP-11C was a mid-range scientific programmable calculator. Compared to the previous series it would fall between the HP-33E/C and HP-34C. It also included two new …

Tough construction: One HP-12C was used by a zoo keeper to calculate feed mixtures. The zoo keeper dropped the calculator and it was consumed by a hippopotamus.

HP-80 History, Design and Interesting Facts Posted by Max Stone on 24 Oct 2013, 4:14 p.m. The World�s First Businessman�s Pocket Calculator Introduction Hewlett-Packard redefined …

This feature time line lists the first time that features appeared on HP's calculators. Only calculators that introduced new features are included in this list.

The HP-25 started on the drawing board as a scientific calculator with a much larger set of functions than the HP-21. By the time it was done, it was that and it was programmable with …

The HP-35 was HP's first pocket calculator. It was introduced at a time when most calculators (including expensive desktop models) had only the four basic functions.

It was the first fully algebraic pocket scientific calculator that HP made. (All of these qualifications are made because HP sold algebraic desktop calculators and desktop and portable computers …

HP adjusted the postfix notation for a calculator keyboard, added a stack to hold the operands and functions to reorder the stack. HP dubbed the result Reverse Polish Notation (RPN) also …

The HP-15C was a high end scientific programmable. To the HP-34C's numerical integration and root solver the HP-15C added complex numbers and matrix calculations.