Mechanical calculator
![Various desktop mechanical calculators used in the office from 1851 onwards. Each one has a different user interface. This picture shows clockwise from top left: An Arithmometer, A Comptometer, A Dalton adding machine, a Sundstrand and an Odhner Arithmometer](/Images/godic/202502/08/Mechanical_calculators_Keyboards1646.png")
![A Chinese Suanpan (the number represented in the picture is 6,302,715,408)](/Images/godic/202502/08/Abacus_61646.png")
![Four of Pascal's calculators and one machine built by Lépine in 1725,[18] Musée des Arts et Métiers](/Images/godic/202502/08/17th-century-mechanical-calculators_-Detail1646.jpg")
![Detail of a replica of an 18th-century calculating machine, designed and built in by the German Johann Helfrich Müller.](/Images/godic/202502/08/Detail_der_Rechenmaschine_von_Johann_Helfrich_Müller1647.jpg")
A mechanical calculator, or calculating machine, was a mechanical device used to perform automatically the basic operations of arithmetic. Most mechanical calculators were comparable in size to small desktop computers and have been rendered obsolete by the advent of the electronic calculator.