A keypad is a small set of buttons arranged in rows and columns, each button labeled with a number, letter, or symbol. You press these buttons to enter information into a device. The number pad on the right side of a computer keyboard is a keypad. So is the grid of buttons on a telephone, a microwave oven, or a door lock that opens when you enter the right code.

Keypads make it quick and easy to type numbers without hunting around a full keyboard. Calculators have keypads so you can rapidly enter math problems. ATM machines use keypads for you to type your PIN. Security systems use keypads to arm and disarm alarms.

Most number keypads arrange digits 1-9 in a grid with 0 at the bottom, though phone keypads and calculator keypads flip this arrangement (phones have 1-2-3 on top, calculators have 7-8-9 on top). This quirk comes from how these devices evolved separately, but both layouts help you enter numbers faster than you could with individual switches or dials.