Millimeter to Astronomical Unit Converter
Unit Converter
Instant · Precise · Universal
32 units available
6 categories total
How to Convert Millimeter to Astronomical Unit
To convert mm to inches: divide by 25.4. To convert inches to mm: multiply by 25.4.
1 mm = 0.001 m = 0.1 cm = 1,000 µm. There are 25.4 mm in one inch.
For example, 1 Millimeter (mm) = 6.684587e-15 Astronomical Unit (AU).
Millimeter to Astronomical Unit — Common Values
| Millimeter (mm) | Astronomical Unit (AU) |
|---|---|
| 0.1 | 6.684587e-16 |
| 0.5 | 3.342294e-15 |
| 1 | 6.684587e-15 |
| 2 | 1.336917e-14 |
| 5 | 3.342294e-14 |
| 10 | 6.684587e-14 |
| 25 | 1.671147e-13 |
| 50 | 3.342294e-13 |
| 100 | 6.684587e-13 |
| 500 | 3.342294e-12 |
| 1000 | 6.684587e-12 |
About Millimeter (mm)
Definition
The millimeter is a unit of length equal to one thousandth of a meter (10⁻³ m), or one tenth of a centimeter.
Mathematical Relationship
1 mm = 0.001 m = 0.1 cm = 1,000 µm. There are 25.4 mm in one inch.
Conversion Formula
To convert mm to inches: divide by 25.4. To convert inches to mm: multiply by 25.4.
Practical Applications
Engineering drawings, screw thread specifications, rainfall measurements, paper thickness, and small component dimensions.
Interesting Facts
Standard A4 paper is 210 × 297 mm. A credit card is about 0.76 mm thick.
Common Mistakes
Confusing mm with cm on rulers — each cm mark has 10 mm divisions. Also, misreading calipers by one mm.
Educational Tips
A dime is about 1.3 mm thick — use it as a quick visual reference for millimeter scale.
About Astronomical Unit (AU)
Definition
The astronomical unit is a unit of length approximating the mean Earth-Sun distance, defined as exactly 149,597,870,700 meters.
Mathematical Relationship
1 AU = 149,597,870,700 m ≈ 149.598 Gm ≈ 499 light-seconds ≈ 8.317 light-minutes.
Conversion Formula
To convert AU to km: multiply by 149,597,870.7. To convert AU to light-years: divide by 63,241.
Practical Applications
Spacecraft mission planning, expressing planetary orbit sizes, and solar system scale models.
Interesting Facts
Light takes about 8 minutes and 20 seconds to travel 1 AU. Mars is about 1.52 AU from the Sun, Jupiter about 5.2 AU.
Common Mistakes
Thinking the AU is the exact Earth-Sun distance — Earth's actual distance varies from ~147 to ~152 Gm over the year due to orbital eccentricity.
Educational Tips
AU makes the solar system manageable: Mercury ≈ 0.39 AU, Venus ≈ 0.72, Earth = 1, Mars ≈ 1.52, Jupiter ≈ 5.2, Saturn ≈ 9.5.