Speed of Light Calculator

Speed of light: c = 299,792,458 m/s ≈ 186,282 miles/second. Light from Sun to Earth: 8 min 20 sec.

What this calculator does

1 light-year = 9.461 × 10¹⁵ meters = 5.879 × 10¹² miles.

How it works

The nearest star (Proxima Centauri) is 4.24 light-years — over 40 trillion km away.

Frequently asked questions

How fast is the speed of light?

299,792,458 meters per second (≈186,282 miles/second or 670,616,629 mph).