# Astronomical Units to Meters (au to m)

Source: https://www.unitconvertercalculator.com/length/astronomical-units-to-meters/

**1 au = 149597870700 m**

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.

## Formula

Convert Astronomical Units to Meters

## Conversion Table

| Astronomical Units (au) | Meters (m) |
|---|---|
| 1.0E-9 au | 149.5978707 m |
| 1.0E-8 au | 1495.978707 m |
| 1.0E-7 au | 14959.78707 m |
| 1.0E-6 au | 149597.8707 m |
| 1.0E-5 au | 1495978.707 m |
| 0.0001 au | 14959787.07 m |
| 0.001 au | 149597870.7 m |
| 0.01 au | 1495978707 m |
| 0.1 au | 14959787070 m |
| 0.39 au | 58343169573 m |
| 0.72 au | 107710466904 m |
| 1 au | 149597870700 m |
| 1.52 au | 227388763464 m |
| 5.2 au | 777908927640 m |

## Units

### 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.

### Meter (m)

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

## Background

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.

## Good to Know

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.

## FAQ

### 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.

## Non-Frequently Asked Questions

### Did NASA ever mess up AU-to-meter conversion?

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.

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## See Also

- [Meters to Astronomical Units](https://www.unitconvertercalculator.com/length/meters-to-astronomical-units/)