Light Year Calculator
Convert light years to other distance units and explore astronomical distances
Light Year Distance Converter
Conversion Result
Example Calculation
Nearest Star Distance
Proxima Centauri: 4.24 light years
In Kilometers: ~40.2 trillion km
In Miles: ~25.0 trillion miles
In AU: ~268,770 AU
Light Year Definition
1 light year = distance light travels in 1 year
Speed of light = 299,792,458 m/s
1 year = 365.25 days (accounting for leap years)
1 light year = 9.461 × 10¹⁵ meters
Quick Reference
Famous Distances
Proxima Centauri
4.24 light years
Sirius
8.6 light years
Galactic Center
26,000 light years
Andromeda Galaxy
2.5 million light years
Observable Universe
93 billion light years
Understanding Light Years
What is a Light Year?
A light year is a unit of distance, not time. It represents the distance that light travels in one year in a vacuum. Since light travels at approximately 299,792,458 meters per second, a light year equals about 9.46 trillion kilometers or 5.88 trillion miles.
Why Use Light Years?
- •Makes astronomical distances more manageable
- •Relates distance to travel time at light speed
- •Standard unit in astronomy and astrophysics
- •Helps visualize the scale of the universe
Calculation Formula
Distance = Speed × Time
1 light year = c × 1 year
- c: Speed of light (299,792,458 m/s)
- 1 year: 365.25 days × 24 hours × 3600 seconds
- Result: 9.460730473 × 10¹⁵ meters
Fun Fact: Light from the Sun takes about 8.3 minutes to reach Earth, so we see the Sun as it was 8.3 minutes ago!