 Convert Kilometres (km) to Light Years (ly) | km in ly
You are: Home > Length > Kilometres to Light Years

# Let's convert Kilometres (km) to Light Years (ly)

This quick and easy calculator will convert Kilometres (km) to Light Years (ly) and show formula, brief history on the units and quick maths for the conversion.

## Quick Reference for Converting Kilometres to Light Years

Formula
ly = km / 9460550000000
Quick Rough Maths
To get the Light Years, divide the number of Kilometres by 9.5 trillion
Kilometres (km) in 1 Light Year
There are 9460550000000 Kilometres in 1 Light Year
Light Years (ly) in 1 Kilometre
There are 0 Light Years in 1 Kilometre

## Unit Information

Kilometre
/ˈkɪləˌmiːtə,kɪˈlɒmɪtə/
Symbol: km
Unit System: SI

### What is the Kilometre?

The kilometre is a unit of length and is a multiple of the metre; an SI derived unit. It has the symbol km.

A kilometre is equal to 1000m, 1094 yards and 0.621 miles.

Kilometres is used to measure road distances in the US, though the UK is still using the imperial "sister" miles.

Light Year
/lʌɪt jɪə,jəː/
Symbol: ly
Unit System: Astronomical System of Units

### What is the Light Year?

The light year is a unit of length in the Astronomical system of units. It uses the symbol ly.

Often confused with a unit of time as it contains the word "year", it is actually defined by the International Astronomical Union (IAU) as the amount of distance that light travels in a vacuum in one Julian year (365.25 days).

Using the speed of light (299,792,458 m/s or 'c') and the Julian year (as apposed to the Gregorian year which is 365.2425 days), we can equivalate 1 light year as 9,460,730,472,580,800 metres or ≈ 9.46 trillion kilometres.