List Of Speed Of Light In Miles Per Second Ideas. 299,792,458 meters per second (exact number) 299,792 kilometers per second (rounded) 3×10 8 m/s (rounded) 186,000 miles per second (rounded) 671,000,000 miles per hour (rounded) 1,080,000,000 kilometers per hour (rounded) is the speed of light really constant? Web in miles per hour/mph, the speed of light is at around 670,616,629, while in kilometers per hour, light travels at 1,079,252,848.

That light from a moving source has the same velocity as light from a stationary source. It can reach the universal speed limit — 186,000 miles per second. Web einstein's theory of special relativity sets of the speed of light, 186,000 miles per second (300 million meters per second), as a cosmic speed limit.