The pocket sized devices became available in the 1970s, especially after the first microprocessor, the Intel 4004, developed by Intel for the Japanese calculator company Busicom. They later became used commonly within the petroleum industry (oil and gas).

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Modern electronic calculators vary: from cheap, give-away, credit-card-sized models to sturdy desktop models with built-in printers. They became popular in the mid-1970s (as integrated circuits made their size and cost small). By the end of that decade, calculator prices had reduced to a point where a basic calculator was affordable to most and they became common in schools.

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Computer operating systems as far back as early Unix have included interactive calculator programs such as dc and hoc, and calculator functions are included in almost all personal digital assistant (PDA) type devices (save a few dedicated address book and dictionary devices).

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In addition to general purpose calculators, there are those designed for specific markets. For example, there are scientific calculators which include trigonometric and statistical calculations. Some calculators even have the ability to do computer algebra. Graphing calculators can be used to graph functions defined on the real line, or higher-dimensional Euclidean space. As of 2016, basic calculators cost little, but the scientific and graphing models tend to cost more.

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In 1986, calculators still represented an estimated 41% of the world's general-purpose hardware capacity to compute information. By 2007, this diminished to less than 0.05%.

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Electronic calculators contain a keyboard with buttons for digits and arithmetical operations; some even contain "00" and "000" buttons to make larger or smaller numbers easier to enter. Most basic calculators assign only one digit or operation on each button; however, in more specific calculators, a button can perform multi-function working with key combinations.

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Calculators usually have liquid-crystal displays (LCD) as output in place of historical light-emitting diode (LED) displays and vacuum fluorescent displays (VFD); details are provided in the section Technical improvements.

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Large-sized figures and comma separators are often used to improve readability. Various symbols for function commands may also be shown on the display. Fractions such as  1⁄3 are displayed as decimal approximations, for example rounded to 0.33333333. Also, some fractions (such as  1⁄7, which is 0.14285714285714; to 14 significant figures) can be difficult to recognize in decimal form; as a result, many scientific calculators are able to work in vulgar fractions or mixed numbers.