# Speed of light

## Definition

The Speed of Light (or c) is the speed at which a photon (an "energy packet" of electromagnetic radiation) travels in a vacuum.

### Values

The exact measurement for the speed of light is 299,792,458 meters per second, in the following values, the speed of light will use values based on the rounded 300,000,000 m/s.

Meters per second:

${\displaystyle c=3\times 10^{8}\mathrm {ms^{-1}} }$

Kilometers per second:

${\displaystyle c=3\times 10^{5}\mathrm {kms^{-1}} }$

Miles per second:

${\displaystyle c=1.9\times 10^{5}\mathrm {mis^{-1}} }$