# Astronomical unit conversions

The astronomical unit conversion selector on this page selects the length/distance measurement unit to convert to starting from astronomical units (AU). To make a conversion starting from a unit of length other than astronomical unit, simply click on the "Reset" button.

## About astronomical unit

The **astronomical unit** is a unit of distance used in astronomy equal to approximately 149,597,870.7 × 10^{3} meters (1 AU ≈ 149.60 × 10^{9} m), the base unit of length in the International System of Units (SI).

One astronomical unit (AU) is also equal to approximately 149.60 × 10^{6} kilometers (km) (an SI unit of length), or 92.956 × 10^{6} miles (mi), or 490.81 × 10^{9} feet (ft) or 1.636 × 10^{11} yards (yd), which are US customary / Imperial units of length.

The astronomical unit is an approximate astronomical measurement unit of distance as it depends on the heliocentric gravitational constant which is the product of the gravitational constant G and the solar mass. Neither the gravitational constant nor the solar mass can be measured to high accuracy in SI units.

Common astronomical measurement units include the parsec (1 AU ≈ 4.8481 × 10^{-6} pc) and the light-year (1 AU ≈ 15.813 × 10^{-6} ly).

Symbol: AU

Plural: astronomical units