The abacus -the first calculators

The first calculators were abaci, and were mainly constructed with a wooden frame with beads that could slide on wires. In centuries before the adoption of the written Arabic numerals system abacuses -the first calculators- were in use, however they are still used by some clerks, fishermen and merchants today.

The 17th century

In 1622 William Oughtred invented the slide rule (an improvement on the first calculators), it was revealed by Richard Delamain (his student), in 1630.

In 1623 Wilhelm Schickard built the first automatic calculator called the "Calculating Clock".

In 1643 Blaise Pascal invented the calculation device known as the Pascaline. This instrument was used for tax calculation in France until 1799.

The 19th century

In 1822 Charles Babbage proposed a mechanical calculator, known as the difference engine. This was capable of manipulating and holding seven numbers, of 31 decimal digits each. Babbage produced two designs for the difference engine and yet another design of an advanced mechanical programmable computer called an analytical engine, a much more advanced device than that of the first calculators. These designs were never completely built by Babbage, but in 1991 the London Science Museum engaged themselves in Babbage's plans; to build a working difference engine using the technology and materials available in the 19th century.

In 1853 Per Georg Scheutz completed a working difference engine based on the designs of Babbage. The machine was about the size of a piano(much larger than any of the first calculators), and was shown at the Exposition Universelle in Paris 1855 and was used to create tables of logarithms.

In 1872 Frank Baldwin invented the pinwheel calculator, W.T. also independently invented a similar design two years later. The Odhner models, and designs from other companies sold thousands, into the 1970s.

In 1875 Martin Wiberg re-designed the Babbage/Scheutz difference engine, into a more compact version that was the size of a sewing machine.

In 1884 Dorr E. Felt invented the Comptometer. Unlike the first calculators, this was the first successful key-driven adding and calculating machine. In 1886 amalgamated with Robert Tarrant to form the Felt & Tarrant Manufacturing Company which went on to make thousands of Comptometers.

In 1891 William S. Burroughs began the commercial manufacture of his printing adding calculator. Burroughs Corporation then became one of the leading companies in the accounting machine and computer businesses.

In 1893 the "Millionaire" calculator was introduced. This was the first calculator that allowed direct multiplication by any digit - "one turn of the crank for each figure in the multiplier".