Light Year Conversion Calculator
Convert light years to kilometers, miles and AU.
A light year is the distance light travels in one year.
How the Math Works
A light year is the distance light travels in one Earth year, calculated as 9.4607 × 10¹² kilometers (approximately 9.5 trillion km). To convert any light year value to kilometers, simply multiply the number of light years by this constant. For miles, divide the kilometer result by 1.60934, and for astronomical units (AU), divide the kilometer value by 149,597,870.7, since 1 AU equals about 150 million km.
Practical Applications
Use this calculator when working with astronomical distances, such as determining how far star systems are from Earth. Enter the light year value to instantly get equivalent distances in kilometers for interplanetary comparisons, in miles for imperial unit contexts, or in AU to understand distances relative to our solar system's scale. Astronomers and space enthusiasts rely on these conversions when studying exoplanets, stellar evolution, or galactic structure.
Day-to-Day Use
While light years seem unimaginably large for daily use, this conversion helps us grasp the vastness of space in familiar terms. Imagine traveling 9.5 trillion kilometers - that's how far your destination would be in a single light year. Understanding these scales enhances our appreciation for cosmic distances, whether reading about the nearest star beyond our sun or the size of our Milky Way galaxy, making space science more relatable and awe-inspiring.
Worked example
1 ly ≈ 9.46 × 10¹² km.
FAQ
Time or distance?
Distance — despite the name, it's how far light goes in a year.