Although there were many developments in the mechanisms and the materials used, the basic operating principles of mechanical calculators / adding machines did not change much from the late 19th century to their obsolescence in the 1970s.

The first calculator or adding machine to be produced in any quantity and actually used was the Pascaline, or Arithmetic Machine, designed and built by the French mathematician and philosopher Blaise Pascal between 1642 and 1644. It could only add and subtract, with numbers being entered by manipulating its dials. Pascal invented the machine for his father, a tax collector. He built 50 of them over the next 10 years.

In 1671 the German mathematician-philosopher Gottfried Wilhelm von Leibniz designed a calculating machine called the Step Reckoner. The Step Reckoner expanded on Pascal’s ideas and did multiplication by repeated addition and shifting.

With the Industrial Revolution of the 18th century came a widespread need to perform repetitive operations efficiently. In 1820 Charles Xavier Thomas de Colmar of France built his Arithmometer, the first commercial mass-produced calculating device. It could perform addition, subtraction, multiplication, and even division. Based on Leibniz’s technology, it was extremely popular and sold for 90 years. The Arithmometer was large enough to cover a desktop.

The first mechanical calculation machines were not very reliable. But they became the basis for the highly successful mechanical calculators built throughout the 19th and 20th century, when more accurate gears and wheels became available.

To learn how pre-computer calculating machines worked, see next page.