Convert Mile to Astronomical Unit
Convert miles to astronomical units instantly. 1 mile = 1.07578e-8 astronomical unit — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Astronomical Unit to Mile converter for the reverse conversion.
Units explained
Mile
A mile (statute mile) is an Imperial and US customary unit of length equal to 5,280 feet or exactly 1,609.344 meters. It is the standard unit for road distances in the United States and the United Kingdom.
The mile derives from the Roman mille passus ("thousand paces" — about 1,480 meters). The English statute mile was fixed at 5,280 feet by the Weights and Measures Act of 1593, and exactly defined as 1,609.344 m by the 1959 International Yard and Pound Agreement.
Miles are used in the US and UK for road signs, speed limits (mph), athletic events (one-mile run), and geographic distances. Aviation also uses statute miles for some visibility measurements.
Roman origin (mille passus); English statute mile fixed at 5,280 feet in 1593; standardized to 1,609.344 m exactly by the 1959 International Yard and Pound Agreement.
Astronomical Unit
The astronomical unit (AU) is a unit of length equal to exactly 149,597,870,700 meters, approximately the average distance from Earth to the Sun. It is the fundamental unit for distance within the solar system.
The AU was originally defined as the semi-major axis of Earth's orbit. In 2012, IAU Resolution B2 redefined the AU as exactly 149,597,870,700 meters, severing its dependence on the actual fluctuating Earth–Sun distance.
AUs are used to express distances within the solar system (Mars: 1.5 AU, Pluto: ~40 AU at perihelion), exoplanet orbital radii, and other planetary-scale distances. Standard in planetary science and astronomy.
Original definition tied to Earth's orbit (Newton, 17th century); fixed at exactly 149,597,870,700 m by IAU Resolution B2 in 2012.
Mile to Astronomical Unit conversion formula
The relationship between miles and astronomical units:
To convert miles to astronomical units, multiply the value in miles by 1.07578e-8. To reverse, multiply astronomical units by 9.295581e+7.
How to use this converter
Type a value into the calculator. The result in astronomical units updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Astronomical Unit to Mile converter for the reverse direction.
Step-by-step: convert miles to astronomical units
- Write down the value in miles (mi).
- Multiply that value by the factor 1.07578e-8.
- The product is the equivalent value in astronomical units (AU).
- To reverse, multiply the astronomical unit value by 9.295581e+7.
Worked examples
Example 1 — Convert 1 mi to AU:
1 × 1.07578e-8 = 1.07578e-8 AU
Example 2 — Convert 100 mi to AU:
100 × 1.07578e-8 = 1.07578e-6 AU
Real-world example — Maritime exclusion zone
A 200-mile exclusion zone (a common maritime boundary) converts to a different value in astronomical units that's useful when describing the same zone in everyday land-distance units.
200 mi × 1.07578e-8 = 2.15156e-6 AU
Real-world example — Coastal cruise distances
A 10-mile coastal sailing route converts to a different value in astronomical units — useful for cruise operators who switch between maritime, aviation, and road-distance units depending on the leg of the trip.
10 mi × 1.07578e-8 = 1.07578e-7 AU
Real-world example — Road-sign distances across systems
A 100-mile road sign converts cleanly into astronomical units — exactly the conversion drivers planning trips abroad rely on when reading road signs in a different measurement system.
100 mi × 1.07578e-8 = 1.07578e-6 AU
Mile to Astronomical Unit conversion table
Standard reference values for converting miles to astronomical units:
| Mile [mi] | Astronomical Unit [AU] |
|---|---|
| 0.01 | 1.07578e-10 |
| 0.1 | 1.07578e-9 |
| 1 | 1.07578e-8 |
| 2 | 2.15156e-8 |
| 3 | 3.22734e-8 |
| 4 | 4.30312e-8 |
| 5 | 5.3789e-8 |
| 10 | 1.07578e-7 |
| 20 | 2.15156e-7 |
| 30 | 3.22734e-7 |
| 40 | 4.30312e-7 |
| 50 | 5.3789e-7 |
| 100 | 1.07578e-6 |
| 500 | 5.3789e-6 |
| 1000 | 1.07578e-5 |
Frequently asked questions
How many astronomical units is 1 mile?
How do I convert miles to astronomical units?
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How many astronomical units is 100 miles?
Popular length unit conversions
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Metric / SI (18 units)
Imperial / US Customary (26 units)
Nautical (1 units)
Astronomical (9 units)
Atomic / Physics (6 units)
Typographic (3 units)
Sources & references
Conversion factor (1 mi = 1.07578e-8 AU) verified against the following authoritative sources:
- BIPM — The International System of Units (SI Brochure 9th ed.)
Official BIPM publication defining the seven SI base units (including the meter) and the rules for their use. The global authority on units of measurement.
- NIST — Guide to the SI
US National Institute of Standards and Technology reference covering the SI base and derived units with definitions and usage rules for US technical practice.
- NIST Special Publication 811 — Guide for the Use of the International System of Units
Detailed NIST guide covering exact conversion factors between SI and US customary units along with formatting and rounding conventions.
- NIST — Refinement of values for the yard and pound (Federal Register 1959)
The treaty (signed by US
- International Astronomical Union — System of Astronomical Constants
The IAU defines astronomical units including the AU (149597870700 m exactly) light-year and parsec used in astronomy and astrophysics.