Links To other calculators sites

Contains an extensive catalogue of  vintage electronic calculators.  

The catalogue shows mark and type, year of introduction , classification-tags and a lot more interesting information

P.S. :

On this site I use some information which I found elsewhere on the internet. If you are the owner of such info and feel abused or would like to be mentioned please let me know.   

On your request I will remove such info or be glad to mention the source.

Thanks to all those collectors who took care of making so much knowledge and experience available to all of us.

This site contains HTML-versions of some original documents related to the early history of calculators. It includes many manuals.

A very interesting site with a lot of information about high-end mechanical calculators. It also contains easy-to-understand drawings regarding common main  working principles.

Robert Mařík’s site contains interesting as well as funny stuff regarding mechanical calculators and calculations on  such machines.

GTB4u   (Dutch)

GTB4u on ETSY   (English)

A very large collection of ink ribbons and other calculator and typewriter related supplies can be ordered from this web shop.  There is a Dutch language webshop and another one in English on Etsy.  
I ordered ribbons several times and experienced fine communication, fast delivery and a high level of user friendliness  each time.  The actual collection is much larger than shown on these web sites. If you can’t find what you’re looking for or are not sure which product fits your machine, ask for help.

The site of Gerald Saudan is dedicated to Madas calculators.  For historical as well as technical information this is a marvellous site.


In addition to information on this link brings you to pages containing extra information about the Walther EMKD., the site of Brent Hilpert contains a lot of detailed technical information of many electronic calculators including reverse engineered schematics of the Canon 131s.  

Mechanical Calculators

(Wim Hasselo)

Wim owns a lot of very nice and some very rare calculators. They all come with a description and lots of perfect photo’s, also of the internals of each machine. For some there is a video.

His site also contains detailed information regarding the many different technologies used in mechanical  calculators.

A yearly printed overview of relevant office equipment available in that year in Germany. Most calculators are mentioned with there price.


Contains a large data base of  mechanical calculators. Available in four languages.

Contains a large data base of  electronic calculators

John Wolff

Contains a lot of information about mechanical as well as electronic calculators.  If you are interested in company history or working principles, don’t, don’t miss this site. If you want to try a repair, look at the Technical and Reference Section. It’s very very helpful.

Is dedicated to Texas Instruments calculators.  Contains extensive catalogue of  TI calculators and also detailed historical information regarding TI,  including the CalTech project which led to the development of the Canon Pocketronic. contains detailed information about the way the Texas Instruments CalTech project  led to the development of the Canon Pocketronic.