Num Lock or Number Lock (⇭) is a key on the

numeric keypad A numeric keypad, number pad, numpad, or ten key, is the calculator-style group of ten numeric keys accompanied by other keys, usually on the far right side of computer keyboard. This grouping allows quick number entry with right hand, ...

of most

computer keyboard A computer keyboard is a built-in or peripheral input device modeled after the typewriter keyboard which uses an arrangement of buttons or Push-button, keys to act as Mechanical keyboard, mechanical levers or Electronic switching system, electro ...

s. It is a lock key, like Caps Lock and Scroll Lock. Its state affects the function of the numeric keypad commonly located to the right of the main keyboard and is commonly displayed by an

LED A light-emitting diode (LED) is a semiconductor device that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons. The color of the light (corresp ...

built into the keyboard. The Num Lock key exists because earlier 84-key

IBM PC keyboard The Keyboard (computing), keyboard for IBM PC-compatible computers is standardized. However, during the more than 30 years of PC architecture being frequently updated, many keyboard layout variations have been developed. A well-known class of IB ...

s did not have cursor control or arrows separate from the numeric keypad. Most earlier computer keyboards had different number keys and cursor control keys; however, to reduce cost, IBM chose to combine the two in their early PC keyboards. Num Lock would be used to select between the two functions. On some laptop computers, the Num Lock key is used to convert part of the main keyboard to act as a (slightly skewed) numeric keypad rather than letters. On some laptop computers, the Num Lock key is absent and replaced by the use of a key combination. Since Apple keyboards never had a combination of arrow keys and numeric keypad (but some lacked arrow keys, function keys, and a numeric keypad altogether), Apple has keyboards with a separate numeric keypad but no functional Num Lock key. Keyboards manufactured by Apple will instead use a ''Clear'' key but not all Apple manufactured keyboards will be provided with it. Numpad

References

Lock keys {{compu-hardware-stub