This site is currently under reconstruction, and many pages are currently unavailable. I apologise for the inconvenience.
This site is intended primarily as a price guide for mechanical calculators. Where production is very low for a particular model, these come onto the market much less frequently. This means that I may have very limited data for sale prices, and the prices also vary more substantially. Please note that information on this website is not a guarantee of the market rate for any model, and that all calculators vary.
Guide to factors which may affect the price of a machine (other than company, model and date)
List of manufacturers, companies and trading names
An excellent list of early mechanical calculators, including all German and most European models, mostly taken from the book 'Die Rechenmaschinen' (Ernst Martin) can be found here.
A pdf of the English translation of this book is available here.
For all machines not covered above, and more general information about manufacturers and history, see here.
An excellent site for general information, although sadly no longer maintained, can be found here.
The Wikipedia page contains an excellent general overview (see here.
A highly comprehensive list of all models of any calculator produced can be found here (https://ifhb.de/Rechenmaschinen.php).
In no particular order, the following are (mostly) the sites of individual collectors.
https://www.rechnen-ohne-strom.de/
http://www.crisvandevel.de/index.htm
http://www.schneemann.de/index.htm
http://machineacalculer.free.fr/
https://www.prehistoriadelainformatica.com/
https://mechanicalcalculators.wordpress.com/
https://photocalcul.com/Calcul/Machines/machines.html
https://mechanicalculator.com/
https://www.calculatinginstruments.com/