HP Calculator History - The HP-35

by Wlodek Mier-Jedrzejowicz Ph.D.


Introduced on July 1 1972, this was the first handheld electronic calculator sold by HP, and the first ever to perform logarithmic and trigonometric functions with one keystroke. As opposed to later HP calculators, it has an x^y function, not y^x, and the trigonometric functions work in degrees only.

The story goes that it was made after William Hewlett was shown a new scientific desktop calculator by his engineers, and asked for a version to fit in his shirt-pocket.

At first, HP thought they would only make a few HP-35s for their own engineers, as no-one else would be interested. Then they decided to try selling it - and sold hundreds of thousands. This means that the HP-35 is not particularly rare, but collectors will pay a good price for one because the HP-35 was the first HP handheld.

We celebrated its twentieth anniversary last year, and articles about it were published in the proceedings of our 1992 conference and in DATAFILE V12N2. The latter article includes details of the three different types of HP-35 made.


This article is part of the WMJARTS file. This file contains a series of articles written by Wlodek Mier-Jedrzejowicz and published in DATAFILE, the journal of the HPCC. The article was reproduced with permission of the author.

Copyright Wlodek Mier-Jedrzejowicz Ph.D.