Convert light years to kilometers

1 ly=9,460,700,000,000km

Use the converter below to change any light years value into kilometers instantly — with formula, conversion table, and real-world examples.

You have

Equals

9,460,700,000,000

Conversion formula

Forward

kilometers = light years × 9,460,700,000,000

Reverse

light years = kilometers × 1.0570e-13

Example: 10 ly × 9,460,700,000,000 = 94,607,000,000,000 km.

About both units

From

Light Year

A light year is the distance light travels in one Julian year — approximately 9.461 × 10¹⁵ meters, or 63,241 AU. It is used in astronomy to describe distances between stars and galaxies. The nearest star to the Sun, Proxima Centauri, is 4.24 light years away.

Real-world: Proxima Centauri, the nearest star beyond the Sun, is 4.24 ly away. The Milky Way is about 100,000 ly across.

Read full light year reference →

Kilometer

The kilometer equals 1000 meters and is the standard unit for road distances in almost every country except the US and UK. Speed limits in Europe, Asia, Australia and most of Africa are given in km/h. A kilometer is roughly 1250 adult walking steps and takes about 12 minutes on foot.

Real-world: London to Paris by Eurostar is 344 km. A full marathon is 42.195 km. Most European motorway speed limits are 120–130 km/h.

Read full kilometer reference →

Light Year to Kilometer conversion table

Common light years to kilometers values for quick reference.

Light Year (ly)	Kilometer (km)
1 ly	9,460,700,000,000 km
5 ly	47,303,500,000,000 km
10 ly	94,607,000,000,000 km
25 ly	236,517,500,000,000 km
50 ly	473,035,000,000,000 km
100 ly	946,070,000,000,000 km
250 ly	2.3652e15 km
500 ly	4.7304e15 km
1,000 ly	9.4607e15 km
5,000 ly	4.7304e16 km

Tips & common mistakes

Quick tips

The light year is a unit of distance, not time, despite the name.
Professional astronomers usually prefer parsecs (1 pc ≈ 3.26 ly) for precision work.
Light from the Andromeda galaxy takes 2.5 million years to reach us — we see it as it was 2.5 Myr ago.

Avoid these

Confusing light year with light second — light second ≈ 300,000 km.
Treating light years as time rather than distance in casual conversation.
Using light years for solar-system distances — use astronomical units (AU) instead.

Frequently asked questions

How many kilometers in a light year?

One light year equals 9,460,700,000,000 kilometers.

How do I convert light years to kilometers?

Multiply the light year value by 9,460,700,000,000 to get the equivalent in kilometers.

What is 100 light years in kilometers?

100 light years equals 946,070,000,000,000 kilometers.

Is a light year bigger than a kilometer?

Yes. 1 light year equals 9,460,700,000,000 kilometers, so one light year is larger.

How to convert light years to kilometers without a calculator?

Multiply by 9,460,700,000,000 for a quick estimate; use a calculator for precise results.

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