How many meters are in 1 AU?

One AU equals exactly 149,597,870,700 meters. This exact value was fixed by IAU Resolution B2 in 2012. It is no longer a measured quantity but a defined constant.

Why was the AU fixed at this exact value?

Before 2012, the AU was defined indirectly through the gravitational constant and solar mass, making it a slightly changing measured value. The IAU fixed it at 149,597,870,700 m to simplify calculations and eliminate the dependency on solar mass measurements.

Is the Earth exactly 1 AU from the Sun?

Not exactly. The Earth's orbit is slightly elliptical, ranging from about 0.983 AU (perihelion in January) to 1.017 AU (aphelion in July). The AU is a defined constant, not the actual instantaneous Earth-Sun distance.

Astronomical Units to Meters (au to m) Converter

1 au = 149,597,870,700 m

1 Astronomical Unit equals 149,597,870,700 Meters (1 au = 149,597,870,700 m). Convert Astronomical Units to Meters with formula, table, and examples.

One astronomical unit equals exactly 149,597,870,700 meters. This is the formal SI definition of the AU, fixed by the International Astronomical Union in 2012. The AU-to-meter conversion is the most fundamental relationship for this unit, connecting solar system distances to the SI base length unit.

How to Convert Astronomical Units to Meters

m = au × 149,597,870,700

Multiply the value in Astronomical Units by 149,597,870,700

Take your value in Astronomical Units
Multiply by 149,597,870,700
Read the result in Meters

Common Astronomical Units to Meters Conversions

Astronomical Units (au)	Meters (m)	Status
1 × 10⁻⁹ au	149.5979 m
1 × 10⁻⁸ au	1,495.9787 m
1 × 10⁻⁷ au	14,959.7871 m
0.000001 au	149,597.8707 m
0.00001 au	1,495,978.707 m
0.0001 au	14,959,787.07 m
0.001 au	149,597,870.7 m
0.01 au	1,495,978,707 m
0.1 au	14,959,787,070 m
0.39 au	58,343,169,573 m
0.72 au	107,710,466,904 m
1 au	149,597,870,700 m
1.52 au	227,388,763,464 m
5.2 au	777,908,927,640 m

Good to Know About Astronomical Units to Meters Conversion

The 2012 IAU definition of the AU as a fixed constant ended centuries of trying to precisely measure the Earth-Sun distance. Now the AU is exact by definition, and the actual Earth-Sun distance varies around it by about 1.7% over the year.

Astronomical Units to Meters: What You Need to Know

The exact value 149,597,870,700 meters was chosen to match the historical mean Earth-Sun distance as closely as possible while being a fixed constant rather than a measured quantity. Before 2012, the AU was defined through the gravitational constant and changed slightly over time. The 2012 fix simplified calculations in celestial mechanics.

What is a Astronomical Unit? au

Exactly 149,597,870,700 meters by IAU 2012 definition. Roughly the average distance from the Earth to the Sun. Used for distances within our solar system.

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Learn more about Astronomical Unit →

What is a Meter? m

The base unit of length in the International System of Units (SI). Used worldwide as the standard measure of distance.

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Learn more about Meter →

Going the other way? Use our Meters to Astronomical Units converter.

Astronomical Units to Meters FAQ

One AU equals exactly 149,597,870,700 meters. This exact value was fixed by IAU Resolution B2 in 2012. It is no longer a measured quantity but a defined constant.
Before 2012, the AU was defined indirectly through the gravitational constant and solar mass, making it a slightly changing measured value. The IAU fixed it at 149,597,870,700 m to simplify calculations and eliminate the dependency on solar mass measurements.
Not exactly. The Earth's orbit is slightly elliptical, ranging from about 0.983 AU (perihelion in January) to 1.017 AU (aphelion in July). The AU is a defined constant, not the actual instantaneous Earth-Sun distance.

Non-Frequently Asked Questions About Astronomical Units to Meters

Questions nobody should ask - but someone did.

NASA lost the Mars Climate Orbiter in 1999 because one team used imperial units while another used metric. It was not AU-to-meters specifically, but the lesson is clear: unit conversion errors can cost $327 million and one spacecraft.