Light Year to Astronomical Unit Converter
Convert Light Year (ly) to Astronomical Unit (AU) instantly. 1 ly = 63,241.077084 AU.
Length Converter
31 units available
1 ly = 63,241.077084 AU
Formula:
AU = ly × 63,241.0770842663With your value: 1 ly = 63,241.07708427 AU
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 Astronomical Unit conversions
Light Year to Astronomical Unit Conversion Table
| Light Year (ly) | Astronomical Unit (AU) |
|---|---|
| 0.5 | 31,620.538542 |
| 1 | 63,241.077084 |
| 2 | 126,482.154169 |
| 5 | 316,205.385421 |
| 10 | 632,410.770843 |
| 15 | 948,616.156264 |
| 20 | 1,264,821.541685 |
| 25 | 1,581,026.927107 |
| 50 | 3,162,053.854213 |
| 100 | 6,324,107.708427 |
| 250 | 15,810,269.271067 |
| 500 | 31,620,538.542133 |
| 1000 | 63,241,077.084266 |
Astronomical Unit to Light Year Conversion Table
| Astronomical Unit (AU) | Light Year (ly) |
|---|---|
| 0.5 | 7.906254e-6 |
| 1 | 1.581251e-5 |
| 2 | 3.162501e-5 |
| 5 | 7.906254e-5 |
| 10 | 0.000158 |
| 15 | 0.000237 |
| 20 | 0.000316 |
| 25 | 0.000395 |
| 50 | 0.000791 |
| 100 | 0.001581 |
| 250 | 0.003953 |
| 500 | 0.007906 |
| 1000 | 0.015813 |
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
Astronomical Unit (AU)
Length
The astronomical unit is exactly 149 597 870 700 m (IAU Resolution B2, 2012).
Source: IAU Resolution B2 (2012) — definition of the astronomical unit; IAU B2 (2015) nominal values
International Astronomical Union · Reviewed 2026-07-01
How to Convert Light Year to Astronomical Unit
To convert from Light Year (ly) to Astronomical Unit (AU), multiply the value by 63,241.0770842663.
Formula: AU = ly × 63,241.0770842663
Reverse: ly = AU × 0.0000158125
Step-by-Step Example
- Start with your value in Light Year. For example: 5 ly
- Multiply by the conversion factor: 5 x 63,241.0770842663
- The result is: 316,205.385421 AU
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 Astronomical Unit
The astronomical unit (AU) is defined as exactly 149,597,870,700 metres, close to the mean Earth–Sun distance. It is the natural yardstick for the Solar System.
Common uses: planetary science, orbital mechanics, astronomy.
Frequently Asked Questions
How many Astronomical Unit are in 1 Light Year?
There are exactly 63,241.0770842663 Astronomical Unit in 1 Light Year. This means the conversion factor from Light Year to Astronomical Unit is 63,241.0770842663.
What is the formula to convert Light Year to Astronomical Unit?
The formula to convert Light Year to Astronomical Unit is: AU = ly × 63,241.0770842663. For example, to convert 10 Light Year to Astronomical Unit, you would multiply 10 by 63,241.0770842663.
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 Astronomical Unit?
The astronomical unit (AU) is defined as exactly 149,597,870,700 metres, close to the mean Earth–Sun distance. It is the natural yardstick for the Solar System.
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 Astronomical Unit converter. UnitConvertLab. Retrieved from https://unitconvertlab.com/convert/light_year-to-astronomical_unit