Light Travel Time
Calculate how long light takes to travel a given distance. Enter distance in AU or km and get travel time in seconds, minutes, hours, days, or years.
Inputs
Results
Light Travel Time
8.32 minutes
Time (seconds)
499.005 s
How to Use This Calculator
- Choose the Distance Unit: AU for solar-system distances or km for specific spacecraft or planetary calculations.
- Enter the Distance value — 1 AU is Earth to Sun, 4.2 AU reaches Jupiter at closest approach.
- Read Light Travel Time in the most relevant unit: seconds for near-Earth objects, minutes for the inner solar system, years for stars.
- Use the Distance (ly) and Distance (pc) outputs to convert your solar-system measurement to stellar-scale units.
- Compare your result to the reference chart showing Moon, Sun, planets, and Pluto for quick sanity-checking.
Formula
t = d / c (c = 299,792.458 km/s; 1 AU = 149,597,870.7 km)Related Calculators
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