Light Year Conversion Calculator
Convert distances between light-years and everyday units like kilometers, miles, and astronomical units.
What is a light-year?
A light-year is the distance light travels in one Julian year (365.25 days) through a vacuum, and it is used to describe the vast distances between stars and galaxies. It equals approximately 9.46 trillion kilometers, or about 5.88 trillion miles.
How this calculator works
Enter a distance and choose which conversion you need. The calculator uses the standard value of 9,460,730,472,580.8 kilometers per light-year (based on the speed of light and the length of a Julian year) to convert between light-years, kilometers, miles, and astronomical units (AU), where 1 light-year equals about 63,241 AU.
- 1 light-year ≈ 9.46 trillion km
- 1 light-year ≈ 5.88 trillion miles
- 1 light-year ≈ 63,241 AU
This calculator is intended for educational and general astronomy reference purposes.