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The Slide Rule
The circular and rectangular slide rule was invented by W. Oughtred. -
Mechanical Calculators
William Schickard (1592 - 1635) succeeded in designing and building the first mechanical calculating device. -
Pascaline
Blaise Pascal (1623 - 1662) invented one of the first calculator, called the Pascaline, to help his father with his work collecting taxes. An improvement on Schickard’s design. -
Arithmometer
The Arithmometer or Arithmomètre was patented in France by Thomas de Colmar (1785-1870). It was the first digital mechanical calculator strong enough and reliable enough to be used daily in an office environment. -
Grant's Calculators
George Barnard Grant (1849-1917) patented and manufactured several models calculating machines. -
Electronic Calculators
William Seward Burroughs (1857 – 1898) filed his first patent for a calculating machine. However, his 1892 patent was for an improved calculating machine with an added printer. -
P100 Burroughs Adding Machine
William Seward Burroughs (1857-1898) invented The Adding Machine as the first in a line of office calculating machines. -
Comptometer
The comptometer was the first commercially successful key-driven mechanical calculator, patented in the USA by Dorr E. Felt (1862-1930). -
Curta Calculator
A small, hand-cranked digital mechanical calculator introduced by Curt Herzstark (1902-1988).
