Light Year Distance Calculator
Convert between light years, kilometers, miles, and astronomical units (AU).
Works in both directions.
Distance Conversion
One light year is the distance light travels in one year in a vacuum.
Key conversion factors:
- 1 light year = 9,460,730,472,580.8 km (9.461 trillion km)
- 1 light year = 5,878,625,373,183.6 miles (5.879 trillion miles)
- 1 light year = 63,241.077 AU (astronomical units)
- 1 AU = 149,597,870.7 km (Earth–Sun distance)
Notable distances in light years:
- Nearest star (Proxima Centauri): 4.24 ly
- Sirius (brightest star): 8.6 ly
- Center of Milky Way: ~26,000 ly
- Andromeda Galaxy: ~2,537,000 ly
- Observable universe radius: ~46.5 billion ly
Speed of light: 299,792.458 km/s (186,282.397 mi/s)