For other uses, see Calculator (disambiguation). A calculator is a electronics device for performing mathematical calculations, distinguished from a computer generally by a limited problem domain and an interface optimized for interactive calculation rather than extensive programming. Calculators can be hardware or software, and mechanical or electronic, and are often built into other devices such as PDAs or mobile phones for the convenience of the user. A basic calculator An old mechanical calculator. A scientific calculator. Modern electronic calculators generally take the form of a small (often pocket-sized) and usually inexpensive computer, designed for low price, portability, and primarily or exclusively interactive operation.