Convert length and distance units — meters, feet, inches, kilometers, miles, light years and more.
| Unit | Name | Value |
|---|---|---|
| 0.001 nmi | 1.238e-11 au | |
| 0.01 nmi | 1.238e-10 au | |
| 0.1 nmi | 1.23797e-09 au | |
| 1 nmi | 1.23797e-08 au | |
| 5 nmi | 6.18984e-08 au | |
| 10 nmi | 1.23797e-07 au | |
| 50 nmi | 6.18984e-07 au | |
| 100 nmi | 1.23797e-06 au | |
| 1000 nmi | 1.23797e-05 au |
Multiply the number of Nautical Miles by 1.238×10-8 to get Astronomical Units. Formula: au = nmi × 1.238×10-8. Example: 10 nmi × 1.238×10-8 = 1.23797e-07 au. To reverse, divide Astronomical Units by 1.238×10-8 to get Nautical Miles.
| Nautical Mile (nmi) | Astronomical Unit (au) |
|---|---|
| 0.001 nmi | 1.238×10-11 au |
| 0.01 nmi | 1.238×10-10 au |
| 0.1 nmi | 1.238×10-9 au |
| 0.5 nmi | 6.1898×10-9 au |
| 1 nmi | 1.238×10-8 au |
| 2 nmi | 2.4759×10-8 au |
| 5 nmi | 6.1898×10-8 au |
| 10 nmi | 1.23797e-07 au |
| 20 nmi | 2.47594e-07 au |
| 50 nmi | 6.18984e-07 au |
| 100 nmi | 1.23797e-06 au |
| 250 nmi | 3.09492e-06 au |
| 500 nmi | 6.18984e-06 au |
| 1000 nmi | 1.23797e-05 au |
| 10000 nmi | 0.000123797 au |
To convert Nautical Mile to Astronomical Unit, multiply by 1.238×10-8. Example: 10 nmi = 1.23797e-07 au
To convert Astronomical Unit back to Nautical Mile, divide by 1.238×10-8 (multiply by 80777500). Use the swap button above.
Start with 100 Nautical Miles = 1.23797e-06 au as your reference point. Scale up or down from there.
Navigation instructors teaching celestial navigation bridge nautical miles (operational navigation unit) with astronomical units (unit of solar system distance) to contextualise how celestial body positions translate to navigational data.
Satellites monitoring maritime traffic use AU-fractions for orbital altitude while tracking ship positions in nautical miles — both units appear in the same satellite maritime surveillance system specification document.
1 AU = 80.78 million nautical miles. Science communicators use this for maritime audiences: "The Sun is 80 million nautical miles away — that's enough sea miles to circumnavigate the Earth over 3,000 times."
Scientists studying subsurface oceans on Europa and Enceladus describe ocean depths in nautical miles for comparison with Earth's oceans, while the moons' distances from Earth use AU — cross-scale conversion needed.
SETI researchers target stars at AU and parsec distances while operating radio telescopes with nautical-mile-scale baseline arrays for VLBI — both units appear in the same radio telescope array design document.
Ocean-observing satellites at AU-fraction orbital distances calibrate altimetry measurements against in-situ buoy positions expressed in nautical miles — engineers convert between both scales in calibration documentation.
The Nautical Mile is a unit of Length measurement (symbol: nmi). 1 nmi = 1.238×10-8 au. Used in scientific and practical Length measurement applications.
The Astronomical Unit is a unit of Length measurement (symbol: au). It is part of an internationally recognised measurement system used alongside the Nautical Mile.
The nautical mile was defined by Earth's own geometry — one minute of arc of latitude along a meridian, approximately 1,852 metres. This elegant definition made it perfect for navigation: on any nautical chart, one nautical mile equals exactly one arcminute, allowing direct distance measurement with dividers without any conversion. The unit was used informally by mariners for centuries before the International Hydrographic Conference standardised it at exactly 1,852 metres in 1929. Today it is universally used in maritime and international aviation — the only two domains that never adopted kilometres for operational distances, largely because the geometric relationship to Earth's circumference remains too useful to abandon.
The astronomical unit has ancient roots — Aristarchus of Samos attempted to measure the Earth-Sun distance around 270 BC. For centuries the AU was estimated using Venus transit observations. Edmond Halley organised the first coordinated international transit-of-Venus expedition in 1716. The modern value was determined by radar ranging to Venus in 1961. The IAU formally defined the AU as exactly 149,597,870,700 metres in 2012 — a fixed constant of physics.
Common use: Nautical Mile to Astronomical Unit conversion is needed when working with international standards, scientific publications, or reference materials that use different unit systems for Length measurement.