An astronomical unit is the mean Earth-Sun distance.
Astronomical units to Nautical miles Converter — AU to nmi
Convert Astronomical unit (AU) to Nautical mile (nmi) using the exact conversion factor (1 astronomical unit = 80,776,388.07 nautical mile). See the formula, worked examples, conversion table, unit comparison, history, and common uses.
Astronomical units to Nautical miles converter
Converter
Length Converter
Convert SI, imperial, US customary, astronomical, scientific, and historical length units.
Context values
Some unit families need one extra value for a physically accurate result.
A nautical mile is exactly 1,852 meters.
Result = input x 1.49597871e+11 / 1852.
Length uses the meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Astronomical units to Nautical miles
Astronomical unit and Nautical mile both measure length. Astronomical unit is typically associated with used internationally in astronomy for solar-system-scale distances., while Nautical mile is typically associated with used internationally in maritime navigation and aviation..
Formula
nautical miles = astronomical units × 80776388.067
This factor comes from each unit's defined relationship to the category's base unit: 1 astronomical unit equals 149597870700 base units, and 1 nautical mile equals 1852 base units, so dividing one by the other gives the direct astronomical unit-to-nautical mile factor of 80776388.067.
Simple example
1 AU × 80776388.07 = 80,776,388.07 nmi
1 astronomical unit = 80,776,388.07 nautical miles.
Real-world example
10 AU × 80776388.07 = 807,763,880.7 nmi
10 astronomical units = 807,763,880.7 nautical miles.
Conversion table
| Astronomical unit (AU) | Nautical mile (nmi) |
|---|---|
| 1 AU | 80,776,388.07 nmi |
| 5 AU | 403,881,940.3 nmi |
| 10 AU | 807,763,880.7 nmi |
| 21.0975 AU | 1,704,179,847 nmi |
| 42.195 AU | 3,408,359,694 nmi |
| 100 AU | 8,077,638,807 nmi |
Reverse conversion: Nautical mile to Astronomical unit
1 nmi × 1.237986e-8 = 1.237986e-8 AU
1 nautical mile = 1.237986e-8 astronomical units.
astronomical units = nautical miles × 1.237986e-8
For a page dedicated to this direction, see Nautical mile to Astronomical unit.
Astronomical unit vs. Nautical mile
| Aspect | Astronomical unit | Nautical mile |
|---|---|---|
| Family | Non-SI unit accepted for use with SI (astronomical) | Non-SI unit accepted for use with SI (maritime/aviation) |
| Typical use | Measuring distances within the solar system (planetary orbits) | Marine and aviation distance and navigation |
| Where it's used | Used internationally in astronomy for solar-system-scale distances. | Used internationally in maritime navigation and aviation. |
Understanding the Astronomical unit
Astronomical unit (AU) measures distance. The astronomical unit is defined as exactly 149,597,870,700 meters, close to the average Earth-Sun distance. It is classified as a Non-SI unit accepted for use with SI (astronomical).
Where it's used: Used internationally in astronomy for solar-system-scale distances.
Uses of the Astronomical unit today
- Measuring distances within the solar system (planetary orbits)
- Astronomical calculations and spacecraft navigation
- Popular science communication about the solar system
History of the Astronomical unit
The astronomical unit originated from 17th-19th century attempts to measure the Earth-Sun distance, refined over time using transits of Venus and later radar and spacecraft ranging.
In 2012, the International Astronomical Union fixed the AU at exactly 149,597,870,700 meters, replacing its earlier definition (tied to gravitational calculations) with a simple fixed distance, independent of the slightly-variable actual Earth-Sun distance.
Historical origin. Astronomical unit was not the invention of a single named person; it developed through the process described above.
Understanding the Nautical mile
Nautical mile (nmi) measures distance. The international nautical mile is defined as exactly 1,852 meters, standardized in 1929. It is classified as a Non-SI unit accepted for use with SI (maritime/aviation).
Where it's used: Used internationally in maritime navigation and aviation.
Uses of the Nautical mile today
- Marine and aviation distance and navigation
- Basis for the knot (nautical miles per hour)
History of the Nautical mile
The nautical mile was historically defined as one minute of latitude along a meridian, directly tying sea navigation to the Earth's geometry, which made it practical for chart-based navigation using a ship's known latitude. The International Hydrographic Bureau standardized it at exactly 1,852 meters in 1929, a value close to the traditional latitude-based definitions used by different countries.
Historical origin. Nautical mile was not the invention of a single named person; it developed through the process described above.
Astronomical unit — sources
- IAU Resolution B2 (2012) — Fixes the astronomical unit at exactly 149,597,870,700 meters.
Nautical mile — sources
- BIPM SI Brochure — Non-SI units accepted for use with SI — Lists the nautical mile among accepted non-SI units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many nautical miles are in 1 astronomical unit?
1 astronomical unit equals 80,776,388.07 nautical miles, using the exact defined conversion factor rather than an estimate.
How do I convert astronomical unit to nautical mile?
Multiply the astronomical unit value by 80776388.07. The converter above does this instantly to whatever precision you set.
How do I convert nautical mile back to astronomical unit?
Use the reverse factor: 1 nautical mile equals 1.237986e-8 astronomical units. You can also use the swap control in the converter above to flip the direction instantly.
What is a astronomical unit?
Astronomical unit (AU) measures distance. The astronomical unit is defined as exactly 149,597,870,700 meters, close to the average Earth-Sun distance. It is classified as a Non-SI unit accepted for use with SI (astronomical).
What is a nautical mile?
Nautical mile (nmi) measures distance. The international nautical mile is defined as exactly 1,852 meters, standardized in 1929. It is classified as a Non-SI unit accepted for use with SI (maritime/aviation).
Is the astronomical unit to nautical mile conversion exact?
Yes. The international nautical mile is defined as exactly 1,852 meters, standardized in 1929. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.
Where is the astronomical unit still used today?
Used internationally in astronomy for solar-system-scale distances.