Kilometers to Nautical Miles
Convert kilometers to nautical miles for maritime and aviation use. Enter any km value — get nautical miles with speed, flight distance, and sea navigation context.
Enter your values above to see the results.
Tips & Notes
- ✓Quick approximation: nm ≈ km × 0.54. A 100 km distance ≈ 54 nm (exact: 53.996 nm). The approximation is accurate to within 0.01%.
- ✓Speed: 1 knot = 1 nautical mile per hour. A ship cruising at 15 knots covers 15 nm/hour = 15 × 1.852 = 27.78 km/h. A commercial aircraft at 480 knots = 480 × 1.852 = 888.96 km/h ≈ 889 km/h.
- ✓The nautical mile is tied directly to latitude: 1 nm = 1 minute of arc (1/60 of a degree) along any meridian. This makes it uniquely useful for navigation because 60 nm = 1 degree of latitude, allowing direct angular-to-distance conversion on sea charts.
- ✓ICAO range for aircraft is always expressed in nautical miles. A Boeing 737-800 range of 5,765 km = 5,765 × 0.539957 = 3,113 nm. Long-haul aircraft like the 787-9 range approximately 14,140 km = 7,635 nm.
- ✓VHF radio coverage at sea: a ship radio with 25W typically reaches 30-40 nm = 55.6-74.1 km. Coastal VHF repeaters extend this range. GMDSS (Global Maritime Distress Safety System) uses nm for all range specifications.
Common Mistakes
- ✗Confusing nautical miles with statute miles — 1 nautical mile = 1.852 km, but 1 statute mile = 1.609 km. They are 15% different. Aviation flight plans and maritime charts use nautical miles; road distances use statute miles.
- ✗Using nm as an abbreviation for nanometers vs. nautical miles — in physics/chemistry, nm = nanometer (10⁻⁹ m). In navigation, nm = nautical mile. Always check context. Aviation and maritime use NM or nmi to reduce ambiguity.
- ✗Applying knots to land speed comparisons without conversion — a vessel doing 20 knots is going 20 × 1.852 = 37.04 km/h. Saying "20 knots is like 20 mph" understates speed by 15% (20 mph = 32.2 km/h, but 20 kts = 37.0 km/h).
- ✗Assuming 1 nm = 1 minute of longitude everywhere — 1 minute of latitude always equals 1 nm (by definition). But 1 minute of longitude varies from 1 nm at the equator to 0 nm at the poles, because meridians converge. Only latitude minutes are constant.
- ✗Using statute miles for flight distance calculations — aviation charts, ATC clearances, and aircraft performance data all use nautical miles. Entering statute miles into a flight computer gives wrong fuel burn and time estimates.
Kilometers to Nautical Miles Overview
The nautical mile is the universal unit of maritime and aviation distance — defined by the geometry of the Earth itself. Its connection to latitude minutes makes it uniquely suited to navigation, while its relationship to the knot (1 nm/hour) provides a seamless speed-distance system used globally at sea and in the air.
Kilometers to nautical miles formula:
nm = km × 0.539957 | 1 nm = 1.852 km exactly | 1 km = 0.539957 nm
EX: Flight distance 1,200 km → 1,200 × 0.539957 = 647.9 nm ≈ 648 nm. Ship voyage 500 km → 500 × 0.539957 = 269.98 nm ≈ 270 nm. At 15 knots: voyage time = 270/15 = 18 hoursSpeed in knots to km/h:
km/h = knots × 1.852 | knots = km/h × 0.539957
EX: Aircraft cruising at 450 knots → 450 × 1.852 = 833.4 km/h. Container ship at 22 knots → 22 × 1.852 = 40.7 km/h. Sailboat at 7 knots → 7 × 1.852 = 12.96 km/hCommon distances in km and nautical miles:
| Distance | Kilometers | Nautical Miles | Context |
|---|---|---|---|
| 1 degree latitude | 111.12 km | 60 nm | Navigation reference |
| Territorial sea | 22.22 km | 12 nm | UNCLOS maritime law |
| EEZ boundary | 370.4 km | 200 nm | Exclusive Economic Zone |
| London to Paris | 389 km | 210 nm | Short-haul flight reference |
| NY to London | 5,570 km | 3,008 nm | Transatlantic reference |
| Earth circumference | 40,075 km | 21,639 nm | 360 degrees × 60 nm/degree |
| Aircraft | Range (km) | Range (nm) | Example Route |
|---|---|---|---|
| Boeing 737-800 | 5,765 km | 3,115 nm | London to Cairo |
| Airbus A321neo | 7,400 km | 3,996 nm | London to New York (eastbound) |
| Boeing 787-9 | 14,140 km | 7,635 nm | London to Auckland |
| Airbus A380 | 15,200 km | 8,208 nm | Dubai to Los Angeles |
| Boeing 777X-9 | 13,500 km | 7,295 nm | Sydney to London |
Frequently Asked Questions
Multiply kilometers by 0.539957. Examples: 100 km = 53.996 nm; 500 km = 269.978 nm; 1,000 km = 539.957 nm; 1,852 km = 1,000 nm (since 1 nm = 1.852 km). Quick check: 185.2 km = 100 nm exactly. For aviation: a flight of 800 km = 800 × 0.539957 = 431.97 nm ≈ 432 nm. For maritime: a voyage of 500 km = 269.98 nm ≈ 270 nm.
A nautical mile is defined as exactly 1,852 meters (1.852 km). It is the international standard for maritime and aviation distance measurement. The nautical mile was originally defined as 1 minute of arc (1/60 of 1 degree) of latitude along any meridian of the Earth. This geographic definition makes it extremely practical: if you are at 45°30 N latitude and sail to 45°31 N, you have traveled exactly 1 nautical mile north. This direct relationship between angular and linear distance makes navigation charts and calculations far simpler than with kilometers or statute miles.
A knot is 1 nautical mile per hour. Ship speed of 15 knots = 15 nm/hour = 15 × 1.852 = 27.78 km/h = 17.26 mph. The term originates from the chip log — a historical speed-measuring tool where sailors counted knots on a rope that paid out over 28 seconds to determine speed. Today, knots are measured electronically but the name persists. Wind speed in aviation and meteorology is always in knots. A gale-force wind of 34-47 knots = 63-87 km/h. Hurricane minimum wind: 64 knots = 118.5 km/h.
1 degree of latitude = 60 nautical miles = 60 × 1.852 = 111.12 km. This relationship is the foundation of nautical navigation: the Earth is divided into 360 degrees of latitude, each degree into 60 minutes, each minute equal to 1 nautical mile. So the total distance from equator to pole (90 degrees) = 90 × 60 = 5,400 nm = 5,400 × 1.852 = 10,000.8 km ≈ 10,000 km (which is why the meter was originally defined as 1/10,000,000 of the equator-to-pole distance). In practice, the Earth is slightly ellipsoidal, so 1 nm varies from 1842.9 m at the equator to 1861.7 m at the poles.
Common flight distances: New York to London 3,459 nm (6,408 km); Los Angeles to Tokyo 4,756 nm (8,815 km); London to Dubai 2,998 nm (5,553 km); Sydney to Singapore 3,907 nm (7,235 km); New York to Los Angeles 2,134 nm (3,953 km). Short-haul reference: London to Paris 210 nm (389 km); New York to Boston 178 nm (330 km). Aircraft range: Boeing 737-800 = 3,115 nm (5,765 km); Airbus A320 ≈ 3,300 nm (6,112 km); Boeing 777-200LR = 9,395 nm (17,395 km) — one of the longest-range commercial aircraft.
International maritime law uses nautical miles for all territorial boundaries. Territorial sea: 12 nm from the baseline (coast). Contiguous zone: 24 nm (used for customs, fiscal, immigration enforcement). Exclusive Economic Zone (EEZ): 200 nm — within which a country has exclusive rights to marine resources including fish, oil, and gas. Continental shelf claims can extend to 350 nm. These distances in kilometers: 12 nm = 22.22 km; 24 nm = 44.45 km; 200 nm = 370.4 km; 350 nm = 648.2 km. The 200 nm EEZ was established by UNCLOS (UN Convention on the Law of the Sea, 1982).