The term “calculator” may be applied to any device that assists the process of calculation. However, in practice it has become shorthand for one such device, the electronic calculator, which was the first to achieve widespread ownership beyond the workplace.

The ancestors of the electronic calculator were the desktop mechanical calculating machines developed in the late nineteenth century. These were based on principles established in the seventeenth century by the French mathematical philosopher Blaise Pascal and the German Gottfried Wilhelm Leibniz and were commonly known as adding machines. By 1900, two main types had emerged: machines operated by setting levers; machines with numerical keyboards, of which the first was the Comptometer of 1886, invented by the American Dorr E. Felt. The American inventor William S. Burroughs developed an adding and listing machine in 1892, with a built-in printing facility for producing a paper record. Adding machines soon became a standard piece of office equipment.

The purely mechanical adding machine evolved into the more compact, electrically powered version, which became typical in the 1950s. The first commercial electronic calculator was a transistorized desktop model introduced by the American Bell Punch Company in 1963. Texas Instruments produced a hand-held electronic calculator in 1967. Early American and Japanese hand-held calculators were still large by today’s standards. Home ownership remained low because people’s needs outside the workplace could be met more cheaply and conveniently by the use of “ready reckoner” tables and slide rules, or simply by mental effort.

The image and role of the calculator changed only when the advent of microelectronics enabled the production of small, cheap calculators. The world’s first true pocket calculator was the Sinclair Executive calculator, designed by the British inventor Clive Sinclair and launched in 1972. It featured an LED (light-emitting diode) display. In the same year, Hewlett-Packard pocket calculators became available in the United States. In 1973, the Japanese company Sharp introduced the first electronic calculator with a liquid crystal display. Within five years, the price of pocket calculators had fallen dramatically. In 1979, the pocket calculator became the card-size calculator when Sharp developed a super-thin model.

The pocket calculator is an example of a product that created demand where it did not previously exist. Today, the sophistication of the pocket calculator has reached such a level that even cheap models incorporate a range of scientific functions well beyond the needs of the average user. More expensive models have larger displays so that results can be presented graphically. The leading manufacturers are Japanese companies such as Casio and Sharp. In environmental terms, the pocket calculator has another distinction: it is the only commonplace device available in a solar-powered form. The solar unit in a calculator is a semiconducting photoelectric cell, which converts light energy into electric energy, thus removing the need for batteries. Pocket calculators may be wholly solar-powered or dual-powered, with back-up battery power to compensate for low light levels.