Nautical Miles to Kilometers: Conversion Chart, Formula and Examples
1 nautical mile = exactly 1.852 kilometers. To convert nautical miles to kilometers, multiply by 1.852. To convert kilometers to nautical miles, divide by 1.852. Use our unit converter for instant calculations across any distance value.
The Conversion Formula
Kilometers → nautical miles: NM = km ÷ 1.852
The factor 1.852 is exact by international definition — not an approximation. The international nautical mile was defined as precisely 1,852 meters by the International Hydrographic Organization in 1929, and ratified by the International Bureau of Weights and Measures. All countries use this standard definition for aviation and maritime purposes.
Nautical Miles to Kilometers Conversion Chart
| Nautical Miles (NM) | Kilometers (km) | Statute Miles (mi) | Meters (m) |
|---|---|---|---|
| 0.5 NM | 0.926 km | 0.575 mi | 926 m |
| 1 NM | 1.852 km | 1.151 mi | 1,852 m |
| 2 NM | 3.704 km | 2.302 mi | 3,704 m |
| 5 NM | 9.26 km | 5.754 mi | 9,260 m |
| 10 NM | 18.52 km | 11.508 mi | 18,520 m |
| 20 NM | 37.04 km | 23.016 mi | 37,040 m |
| 50 NM | 92.6 km | 57.539 mi | 92,600 m |
| 100 NM | 185.2 km | 115.078 mi | 185,200 m |
| 200 NM | 370.4 km | 230.156 mi | 370,400 m |
| 500 NM | 926 km | 575.39 mi | 926,000 m |
| 1,000 NM | 1,852 km | 1,150.78 mi | 1,852,000 m |
Why Is 1 Nautical Mile Exactly 1.852 km?
The nautical mile has a geometric origin tied to Earth's meridional circumference. One degree of latitude spans approximately 111.12 kilometers. Dividing by 60 (the number of arcminutes in one degree of latitude) gives:
This is why nautical miles dominate navigation:
- On any nautical chart, 1 degree of latitude = exactly 60 nautical miles.
- If your GPS reads 48.5°N and you navigate to 49.5°N, the north-south distance is exactly 60 nautical miles — readable directly from coordinates.
- Pilots and mariners convert position coordinates to distances without lookup tables, just arithmetic.
Earth is not a perfect sphere (it is an oblate spheroid), so the actual arc length of one arcminute of latitude varies slightly — from approximately 1.842 km at the equator to 1.861 km at the poles. The standardized 1.852 km is the internationally agreed average, defined as exact since 1929.
Nautical Miles vs Statute Miles vs Kilometers
| Unit | In Meters (exact) | Vs 1 Nautical Mile | Primary Use |
|---|---|---|---|
| Nautical Mile (NM) | 1,852 m | 1.000 NM | Aviation, maritime navigation, international law |
| Statute Mile (mi) | 1,609.344 m | 0.869 NM | Road distances (US, UK) |
| Kilometer (km) | 1,000 m | 0.540 NM | International standard (most countries) |
A nautical mile is 15.08% longer than a statute mile (1.852 ÷ 1.609 = 1.1508). When pilots and ships report speed in knots (nautical miles per hour), the conversions are: 1 knot = 1.852 km/h = 1.151 mph. A container ship doing 18 knots covers 33.3 km/h — or 800 km in approximately 24 hours.
Worked Examples
Example 1: London to New York flight distance
The great circle route from London Heathrow (LHR) to John F. Kennedy (JFK) is approximately 3,459 nautical miles.
In kilometers: 3,459 NM × 1.852 = 6,406 km
At a typical cruise speed of 480 knots (889 km/h), flight time = 6,406 ÷ 889 ≈ 7.2 hours. Actual times vary with jet stream and routing.
Example 2: UN Exclusive Economic Zone (200 NM limit)
Under UNCLOS (UN Convention on the Law of the Sea), nations can claim an Exclusive Economic Zone extending 200 nautical miles from their coastline.
In kilometers: 200 NM × 1.852 = 370.4 km
The EEZ grants sovereign rights over fishing, oil, and gas within this 370.4 km offshore buffer.
Example 3: Coastal sailing passage
A sailor plans a passage 45 nautical miles at a boat speed of 6 knots.
In kilometers: 45 NM × 1.852 = 83.34 km
Estimated passage time: 45 ÷ 6 = 7.5 hours (not accounting for current or wind)
Applications of Nautical Miles
- International aviation: ICAO (International Civil Aviation Organization) mandates nautical miles and knots for all commercial aviation worldwide. A Boeing 737 cruises at ~450 knots (833 km/h) over distances measured in nautical miles on all flight plans.
- Maritime shipping: Ship speeds (knots) and route distances (nautical miles) are universal in commercial shipping. Global trade routes are published in nautical miles — the Suez Canal route from Rotterdam to Singapore is approximately 11,200 NM (20,742 km).
- International maritime law: Territorial seas (12 NM), contiguous zones (24 NM), and EEZs (200 NM) are all defined in nautical miles under UNCLOS, signed by 168 nations.
- Search and rescue: Maritime rescue coordinates use nautical miles for consistent international communication between coast guards and rescue services across different countries.
- Weather and oceanography: Storm tracks, ocean current speeds (in knots), and sea ice extent are often reported in nautical miles for compatibility with maritime and aviation systems.
Related Conversion Guides
- kg to lbs conversion chart and formula 2026
- Celsius to Fahrenheit: full conversion chart
- Meters to feet: height conversion chart
Frequently Asked Questions
How many kilometers is 1 nautical mile?
1 nautical mile = exactly 1.852 kilometers (1,852 meters). This is the international standard definition adopted in 1929. The conversion factor is exact — not an approximation — because the nautical mile is defined as precisely 1,852 meters.
How do you convert nautical miles to kilometers?
Multiply nautical miles by 1.852. For the reverse, divide kilometers by 1.852. Quick examples: 10 NM = 18.52 km. 50 NM = 92.6 km. 100 NM = 185.2 km. 200 NM = 370.4 km.
What is the difference between a nautical mile and a regular mile?
A nautical mile (1,852 m) is 15% longer than a statute mile (1,609 m). 1 nautical mile = 1.15078 statute miles. Nautical miles are used in aviation and maritime navigation globally. Statute miles are used for road distances in the US and UK.
Why are nautical miles used in navigation?
1 nautical mile equals 1 arcminute of latitude on Earth's surface. This means 1 degree of latitude = exactly 60 nautical miles — navigators can read distance directly from latitude coordinate differences. This geometric relationship makes nautical miles the standard in all commercial aviation and maritime navigation worldwide.