A calculator is an electronic device used for performing mathematical calculations. It typically consists of a keypad for inputting numbers and mathematical operations, a display screen to show the results, and various function buttons for performing specific calculations such as addition, subtraction, multiplication, division, square root, etc. Calculators can be basic with limited functions or advanced with scientific or graphing capabilities. They are widely used in various fields such as education, finance, engineering, and everyday life for quick and accurate calculations.