Convert Nautical Mile to Kilometer
Convert nautical miles to kilometers instantly. 1 nautical mile = 1.852 kilometer — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Kilometer to Nautical Mile converter for the reverse conversion.
Units explained
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.
Kilometer
A kilometer is a metric unit of length equal to one thousand meters. It is the standard unit for measuring road distances, geographic distances, and other large-scale measurements in metric countries.
The kilometer was defined alongside the meter in 1795 using the standard SI prefix kilo- (from Greek chilioi, "thousand"), denoting one thousand units.
Kilometers are used worldwide (except the United States and a few others) for road signage, geographic distance, athletic events, and scientific distances at planetary scale. Speed limits in most countries are given in km/h.
Adopted 1795 in France as part of the original metric system; the kilometer became the global standard for road and geographic distance through the 19th and 20th century metric adoption.
Nautical Mile to Kilometer conversion formula
The relationship between nautical miles and kilometers:
To convert nautical miles to kilometers, multiply the value in nautical miles by 1.852. To reverse, multiply kilometers by 0.5399568035.
How to use this converter
Type a value into the calculator. The result in kilometers updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Kilometer to Nautical Mile converter for the reverse direction.
Step-by-step: convert nautical miles to kilometers
- Write down the value in nautical miles (nmi).
- Multiply that value by the factor 1.852.
- The product is the equivalent value in kilometers (km).
- To reverse, multiply the kilometer value by 0.5399568035.
Worked examples
Example 1 — Convert 1 nmi to km:
1 × 1.852 = 1.852 km
Example 2 — Convert 100 nmi to km:
100 × 1.852 = 185.2 km
Real-world example — Exclusive Economic Zone (EEZ)
A 200-nautical-mile EEZ equals 370.4 km. Maritime lawyers and coast guards convert nmi to km when describing the EEZ boundary to land-side authorities who think in road-network distances.
200 nmi × 1.852 = 370.4 km
Real-world example — Territorial-waters boundary
A 12-nautical-mile territorial-waters boundary equals 22.224 km. International maritime treaties define the boundary in nmi; coastal-mapping projects routinely convert this to km for the land-side mapping coordinate system.
12 nmi × 1.852 = 22.224 km
Real-world example — One nautical mile to kilometers
1 nautical mile equals exactly 1.852 km. Pilots and ship's officers convert nmi to km whenever they cross-reference aviation/marine charts (nautical miles) with road-network maps (kilometres) — every flight plan and shipping route does this.
1 nmi × 1.852 = 1.852 km
Nautical Mile to Kilometer conversion table
Standard reference values for converting nautical miles to kilometers:
| Nautical Mile [nmi] | Kilometer [km] |
|---|---|
| 0.01 | 0.01852 |
| 0.1 | 0.1852 |
| 1 | 1.852 |
| 2 | 3.704 |
| 3 | 5.556 |
| 4 | 7.408 |
| 5 | 9.26 |
| 10 | 18.52 |
| 20 | 37.04 |
| 30 | 55.56 |
| 40 | 74.08 |
| 50 | 92.6 |
| 100 | 185.2 |
| 500 | 926 |
| 1000 | 1852 |
Frequently asked questions
How many kilometers is 1 nautical mile?
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How many kilometers is 100 nautical miles?
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Metric / SI (7 units)
Sources & references
Conversion factor (1 nmi = 1.852 km) 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.