* 299,792,458 meters per second (m/s) in a vacuum.

This speed is often rounded to 3 x 10^8 m/s for easier calculations.

It's important to note that:

* The speed of light is a universal constant, meaning it is the same for all electromagnetic waves, regardless of their frequency or wavelength.

* The speed of light can be slightly slower in mediums other than a vacuum, such as air or water.