✨ Speed of Light Travel
Time to travel any distance at speed of light
About this calculator
Light is the universe's speed limit at 299,792,458 metres per second, and this calculator shows what that means for travel times. Enter any distance — across the city, to the Moon, to Mars, to the nearest star — and see how long light takes to cover it, from fractions of a second to years.
Time equals distance divided by the speed of light. Sunlight is about 8 minutes old when it reaches Earth, the Moon is 1.3 light-seconds away, and Proxima Centauri is 4.24 light-years — which is why interstellar chat would have an 8.5-year round-trip lag.
Tip: Nothing with mass can reach light speed — accelerating mass to c would take infinite energy. These times are the absolute minimum any signal or ship could ever manage.