Light Year to Kilometer Converter
Convert Light Year (ly) to Kilometer (km) instantly. 1 ly = 9.460730e+12 km.
Length Converter
31 units available
1 ly = 9.460730e+12 km
Formula:
km = ly × 9.460730e+12With your value: 1 ly = 9.460730e+12 km
How big is that?
Everyday references on a logarithmic scale, all expressed in light year so you can sanity-check the result.
Other Light Year to Kilometer conversions
Light Year to Kilometer Conversion Table
| Light Year (ly) | Kilometer (km) |
|---|---|
| 0.5 | 4.730365e+12 |
| 1 | 9.460730e+12 |
| 2 | 1.892146e+13 |
| 5 | 4.730365e+13 |
| 10 | 9.460730e+13 |
| 15 | 1.419110e+14 |
| 20 | 1.892146e+14 |
| 25 | 2.365183e+14 |
| 50 | 4.730365e+14 |
| 100 | 9.460730e+14 |
| 250 | 2.365183e+15 |
| 500 | 4.730365e+15 |
| 1000 | 9.460730e+15 |
Kilometer to Light Year Conversion Table
| Kilometer (km) | Light Year (ly) |
|---|---|
| 0.5 | 5.285004e-14 |
| 1 | 1.057001e-13 |
| 2 | 2.114002e-13 |
| 5 | 5.285004e-13 |
| 10 | 1.057001e-12 |
| 15 | 1.585501e-12 |
| 20 | 2.114002e-12 |
| 25 | 2.642502e-12 |
| 50 | 5.285004e-12 |
| 100 | 1.057001e-11 |
| 250 | 2.642502e-11 |
| 500 | 5.285004e-11 |
| 1000 | 1.057001e-10 |
Where these values come from
Every factor on this page is traced to the document that defines it. See the full provenance dataset or our methodology.
Light Year (ly)
Length
A light-year is the distance light travels in one Julian year: 9 460 730 472 580 800 m exactly.
Source: IAU Resolution B2 (2012) — definition of the astronomical unit; IAU B2 (2015) nominal values
International Astronomical Union · Reviewed 2026-07-01
Kilometer (km)
Length
Traceable to the metre, defined by fixing the speed of light in vacuum at 299 792 458 m/s. Imperial lengths derive from the 1959 international yard (0.9144 m exactly).
Source: BIPM, The International System of Units (SI), 9th edition, 2019 (updated 2024)
Bureau International des Poids et Mesures · Reviewed 2026-07-01
How to Convert Light Year to Kilometer
To convert from Light Year (ly) to Kilometer (km), multiply the value by 9.460730e+12.
Formula: km = ly × 9.460730e+12
Reverse: ly = km × 1.057001e-13
Step-by-Step Example
- Start with your value in Light Year. For example: 5 ly
- Multiply by the conversion factor: 5 x 9.460730e+12
- The result is: 4.730365e+13 km
About Light Year
A light year is the distance light travels through a vacuum in one Julian year — exactly 9,460,730,472,580,800 metres. It is a unit of distance, not of time.
Fun Fact: Proxima Centauri, the nearest star to the Sun, sits about 4.25 light years away.
Common uses: astronomy, popular science, education.
About Kilometer
The kilometer equals 1,000 meters and is the standard unit for measuring distances between geographical locations in most countries.
Fun Fact: The circumference of Earth is approximately 40,075 km.
Common uses: road distances, geography, running.
Frequently Asked Questions
How many Kilometer are in 1 Light Year?
There are exactly 9.460730e+12 Kilometer in 1 Light Year. This means the conversion factor from Light Year to Kilometer is 9.460730e+12.
What is the formula to convert Light Year to Kilometer?
The formula to convert Light Year to Kilometer is: km = ly × 9.460730e+12. For example, to convert 10 Light Year to Kilometer, you would multiply 10 by 9.460730e+12.
What is a Light Year?
A light year is the distance light travels through a vacuum in one Julian year — exactly 9,460,730,472,580,800 metres. It is a unit of distance, not of time.
What is a Kilometer?
The kilometer equals 1,000 meters and is the standard unit for measuring distances between geographical locations in most countries.
What are the common uses of Light Year?
The Light Year is commonly used in astronomy, popular science, education.
Related Length Conversions
Cite this page
UnitConvertLab. (2026). Light Year to Kilometer converter. UnitConvertLab. Retrieved from https://unitconvertlab.com/convert/light_year-to-kilometer