Convert Mil to Nautical Mile
Convert mils to nautical miles instantly. 1 mil = 1.37149e-8 nautical mile — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Nautical Mile to Mil converter for the reverse conversion.
Units explained
Mil
A mil (also called a thou) is an Imperial unit of length equal to one thousandth of an inch (1/1000 in = 0.0254 mm = 25.4 μm exactly). It is used in engineering, manufacturing, and materials specifications.
The mil is derived from the Latin mille, "thousand," denoting one-thousandth of an inch. Standardized in industrial use during the 19th-century rise of precision engineering.
Mils are used to specify thicknesses of plastic films, foils, paper, copper traces on printed circuit boards (PCBs), wire insulation, and paint coatings. A standard sheet of paper is about 4 mils thick.
Adopted in 19th-century engineering practice; the value (1/1000 in) became exact in 1959 when the inch was fixed at 25.4 mm via the International Yard and Pound Agreement. The British term is "thou"; American term is "mil".
Nautical Mile
A nautical mile is a unit of length equal to exactly 1,852 meters, defined as one minute of arc along any meridian of the Earth. It is the standard unit for sea and air navigation worldwide.
Originally defined as one minute of arc along a great circle of the Earth, making it convenient for celestial navigation. The International Hydrographic Organization (IHO) standardized the value at exactly 1,852 meters in 1929.
Nautical miles are used in maritime navigation, aviation, and international law (territorial waters, exclusive economic zones). Speed in nautical miles per hour is called a knot. The nautical mile is distinct from the statute (land) mile.
Defined for celestial navigation since antiquity; standardized to 1,852 m exactly by the IHO in 1929; adopted by the International Civil Aviation Organization (ICAO) for aviation use.
Mil to Nautical Mile conversion formula
The relationship between mils and nautical miles:
To convert mils to nautical miles, multiply the value in mils by 1.37149e-8. To reverse, multiply nautical miles by 7.291339e+7.
How to use this converter
Type a value into the calculator. The result in nautical miles updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Nautical Mile to Mil converter for the reverse direction.
Step-by-step: convert mils to nautical miles
- Write down the value in mils (mil).
- Multiply that value by the factor 1.37149e-8.
- The product is the equivalent value in nautical miles (nmi).
- To reverse, multiply the nautical mile value by 7.291339e+7.
Worked examples
Example 1 — Convert 1 mil to nmi:
1 × 1.37149e-8 = 1.37149e-8 nmi
Example 2 — Convert 100 mil to nmi:
100 × 1.37149e-8 = 1.37149e-6 nmi
Real-world example — Feature-scale to long-haul
One billion mils equals exactly one nautical mile — the conversion an optical-network engineer performs when totalling feature-level path lengths into a single long-haul fiber-link distance.
1e+9 mil × 1.37149e-8 = 13.7149028078 nmi
Real-world example — Fiber-optic link lengths
Converting from microscale mils to the nautical miles of a long-haul fiber link is the conversion an optical engineer performs when calculating attenuation per kilometre of fiber.
1e+9 mil × 1.37149e-8 = 13.7149028078 nmi
Mil to Nautical Mile conversion table
Standard reference values for converting mils to nautical miles:
| Mil [mil] | Nautical Mile [nmi] |
|---|---|
| 0.01 | 1.37149e-10 |
| 0.1 | 1.37149e-9 |
| 1 | 1.37149e-8 |
| 2 | 2.742981e-8 |
| 3 | 4.114471e-8 |
| 4 | 5.485961e-8 |
| 5 | 6.857451e-8 |
| 10 | 1.37149e-7 |
| 20 | 2.742981e-7 |
| 30 | 4.114471e-7 |
| 40 | 5.485961e-7 |
| 50 | 6.857451e-7 |
| 100 | 1.37149e-6 |
| 500 | 6.857451e-6 |
| 1000 | 1.37149e-5 |
Frequently asked questions
How many nautical miles is 1 mil?
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Imperial / US Customary (26 units)
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Sources & references
Conversion factor (1 mil = 1.37149e-8 nmi) 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 Hydrographic Organization — Resolution on the Nautical Mile
International authority that standardised the nautical mile at exactly 1852 m in 1929 — the value adopted worldwide for sea and air navigation.