---
title: "Millimeters to Astronomical units — mm to AU converter"
description: "1 millimeter = 6.685 × 10^-15 astronomical units. Conversion table, the exact formula, and a calculator for any value."
url: https://atoneplace.net/convert/mm-to-astronomical-units/
site: "At One Place"
---

# Millimeters to astronomical units

**1 millimeter in astronomical units: 1 mm = 6.685 × 10^-15 AU**

AU = mm × 6.684587122 × 10^-15

To convert millimeters to astronomical units, multiply by 6.684587122 × 10^-15. The table below gives the values people look up most often, and the converter works for any number.

## Millimeters to astronomical units table

*Common millimeter values converted to astronomical units.*

| Millimeters | Astronomical units |
| --- | --- |
| 1 mm | 6.685 × 10^-15 |
| 2 mm | 1.337 × 10^-14 |
| 3 mm | 2.005 × 10^-14 |
| 4 mm | 2.674 × 10^-14 |
| 5 mm | 3.342 × 10^-14 |
| 10 mm | 6.685 × 10^-14 |
| 15 mm | 1.003 × 10^-13 |
| 20 mm | 1.337 × 10^-13 |
| 25 mm | 1.671 × 10^-13 |
| 30 mm | 2.005 × 10^-13 |
| 40 mm | 2.674 × 10^-13 |
| 50 mm | 3.342 × 10^-13 |
| 75 mm | 5.013 × 10^-13 |
| 100 mm | 6.685 × 10^-13 |
| 250 mm | 1.671 × 10^-12 |
| 500 mm | 3.342 × 10^-12 |
| 1,000 mm | 6.685 × 10^-12 |

## How the conversion works

The relationship is AU = mm × 6.684587122 × 10^-15. Both units measure length, so the conversion is a fixed factor that never changes.

## Common questions

### How many astronomical units are in one millimeter?

One millimeter equals 6.685 × 10^-15 astronomical units. AU = mm × 6.684587122 × 10^-15.

### How do you convert millimeters to astronomical units?

Use AU = mm × 6.684587122 × 10^-15. So 10 mm is 6.685 × 10^-14 AU.

### How many millimeters are in one astronomical unit?

One astronomical unit equals 149,597,870,000,000 millimeters, which is the reverse of the conversion above.

## Related pages

- [Astronomical units to Millimeters](https://atoneplace.net/convert/astronomical-units-to-mm/)
- [Millimeters to Meters](https://atoneplace.net/convert/mm-to-meters/)
- [Millimeters to Kilometers](https://atoneplace.net/convert/mm-to-km/)
- [Millimeters to Centimeters](https://atoneplace.net/convert/mm-to-cm/)
- [Millimeters to Miles](https://atoneplace.net/convert/mm-to-miles/)
- [Millimeters to Yards](https://atoneplace.net/convert/mm-to-yards/)
- [Millimeters to Feet](https://atoneplace.net/convert/mm-to-feet/)
- [Millimeters to Inches](https://atoneplace.net/convert/mm-to-inches/)

## Sources

- Guide for the Use of the International System of Units (SP 811) — NIST (https://www.nist.gov/pml/special-publication-811) [Public domain (US Government)]
- The International System of Units (SI Brochure) — Bureau International des Poids et Mesures (https://www.bipm.org/en/publications/si-brochure)
- Calculated on this page — At One Place (/about/)