A calculator is a device or tool used for performing mathematical calculations quickly and accurately. It typically consists of a keypad for inputting numbers and mathematical operations, a display screen for showing the input and results, and various function buttons for performing specific operations such as addition, subtraction, multiplication, division, exponentiation, square roots, and more.

Modern calculators come in various forms, including handheld devices, desktop models, software applications for computers and mobile devices, and online calculator websites. They may have additional features such as memory storage, scientific functions, programmability, graphing capabilities, and specialized functions for specific fields such as finance, engineering, or statistics.