## ››Convert astronomical unit to light year

 astronomical unit light-year

How many astronomical unit in 1 light-year? The answer is 63241.077088071.
We assume you are converting between astronomical unit and light year.
You can view more details on each measurement unit:
astronomical unit or light-year
The SI base unit for length is the metre.
1 metre is equal to 6.6845871226706E-12 astronomical unit, or 1.0570008340246E-16 light-year.
Note that rounding errors may occur, so always check the results.
Use this page to learn how to convert between astronomical units and light years.
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## ››Definition: Astronomical unit

The astronomical unit (AU or au or a.u. or sometimes ua) is a unit of length. It is approximately equal to the mean distance between the Earth and Sun. The currently accepted value of the AU is 149 597 870 691 ± 30 metres (about 150 million kilometres or 93 million miles).

The symbol "ua" is recommended by the Bureau International des Poids et Mesures, but in the United States and other anglophone countries the reverse usage is more common. The International Astronomical Union recommends "au" and international standard ISO 31-1 uses "AU".

## ››Definition: Light-year

A light year, abbreviated ly, is the distance light travels in one year: roughly 9.46 × 1012 kilometres (9.46 petametres, or about 5.88 × 1012 (nearly six trillion) miles). More specifically, a light year is defined as the distance that a photon would travel, in free space and infinitely far away from any gravitational or magnetic fields, in one Julian year (365.25 days of 86400 seconds each).

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