Millimeter to Astronomical Unit Converter
Convert Millimeter (mm) to Astronomical Unit (AU) instantly. 1 mm = 6.684587e-15 AU.
Length Converter
31 units available
1 mm = 6.684587e-15 AU
Formula:
AU = mm × 6.684587e-15With your value: 1 mm = 6.684587e-15 AU
How big is that?
Everyday references on a logarithmic scale, all expressed in millimeter so you can sanity-check the result.
Other Millimeter to Astronomical Unit conversions
Millimeter to Astronomical Unit Conversion Table
| Millimeter (mm) | Astronomical Unit (AU) |
|---|---|
| 0.5 | 3.342294e-15 |
| 1 | 6.684587e-15 |
| 2 | 1.336917e-14 |
| 5 | 3.342294e-14 |
| 10 | 6.684587e-14 |
| 15 | 1.002688e-13 |
| 20 | 1.336917e-13 |
| 25 | 1.671147e-13 |
| 50 | 3.342294e-13 |
| 100 | 6.684587e-13 |
| 250 | 1.671147e-12 |
| 500 | 3.342294e-12 |
| 1000 | 6.684587e-12 |
Astronomical Unit to Millimeter Conversion Table
| Astronomical Unit (AU) | Millimeter (mm) |
|---|---|
| 0.5 | 7.479894e+13 |
| 1 | 1.495979e+14 |
| 2 | 2.991957e+14 |
| 5 | 7.479894e+14 |
| 10 | 1.495979e+15 |
| 15 | 2.243968e+15 |
| 20 | 2.991957e+15 |
| 25 | 3.739947e+15 |
| 50 | 7.479894e+15 |
| 100 | 1.495979e+16 |
| 250 | 3.739947e+16 |
| 500 | 7.479894e+16 |
| 1000 | 1.495979e+17 |
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.
Millimeter (mm)
Length
Traceable to the metre, defined by fixing the speed of light in vacuum at 299 792 458 m/s. Imperial lengths derive from the 1959 international yard (0.9144 m exactly).
Source: BIPM, The International System of Units (SI), 9th edition, 2019 (updated 2024)
Bureau International des Poids et Mesures · 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 Millimeter to Astronomical Unit
To convert from Millimeter (mm) to Astronomical Unit (AU), multiply the value by 6.684587e-15.
Formula: AU = mm × 6.684587e-15
Reverse: mm = AU × 1.495979e+14
Step-by-Step Example
- Start with your value in Millimeter. For example: 5 mm
- Multiply by the conversion factor: 5 x 6.684587e-15
- The result is: 3.342294e-14 AU
About Millimeter
The millimeter equals one thousandth of a meter and is used for precise measurements in engineering and manufacturing.
Common uses: engineering, rainfall measurement, manufacturing.
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 Millimeter?
There are exactly 6.684587e-15 Astronomical Unit in 1 Millimeter. This means the conversion factor from Millimeter to Astronomical Unit is 6.684587e-15.
What is the formula to convert Millimeter to Astronomical Unit?
The formula to convert Millimeter to Astronomical Unit is: AU = mm × 6.684587e-15. For example, to convert 10 Millimeter to Astronomical Unit, you would multiply 10 by 6.684587e-15.
What is a Millimeter?
The millimeter equals one thousandth of a meter and is used for precise measurements in engineering and manufacturing.
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 Millimeter?
The Millimeter is commonly used in engineering, rainfall measurement, manufacturing.
Related Length Conversions
Cite this page
UnitConvertLab. (2026). Millimeter to Astronomical Unit converter. UnitConvertLab. Retrieved from https://unitconvertlab.com/convert/millimeter-to-astronomical_unit