Kilometers to Nautical Miles Converter

How many kilometers are in a nautical mile?

The international nautical mile is exactly 1,852 meters, or 1.852 kilometers. It is written M, NM or nmi. Dividing one kilometer by that length gives about 0.539957 nautical miles.

nautical miles = kilometers ÷ 1.852To convert nautical miles to kilometers, multiply by 1.852.

The nautical mile is not an SI unit, but the SI brochure lists it among the non-SI units that remain in use alongside the metric system, mainly for navigation at sea and in the air.

Why the nautical mile is 1,852 meters

A nautical mile began as the length of one minute of latitude, a sixtieth of a degree measured along a meridian. That makes position and distance easy to read together on a chart: sixty nautical miles of northward travel changes your latitude by one degree. Because the Earth is slightly flattened, a real minute of latitude ranges from about 1,843 m at the equator to about 1,862 m near the poles, so in 1929 an international conference settled on the round value of 1,852 m.

The idea still checks out against the planet. A circle has 21,600 minutes, and 21,600 × 1.852 km = 40,003.2 km, very close to the Earth's roughly 40,000 km circumference around the poles. Speed follows the same logic: one knot is one nautical mile per hour, which equals 1.852 km/h.

How to convert kilometers to nautical miles

1. Enter the distance in kilometers in the first box.
2. Read the distance in nautical miles in the second box; it updates as you type.
3. To convert back, multiply nautical miles by 1.852.

Example 1. A ferry route is 150 km long. 150 ÷ 1.852 = 80.993521 nautical miles.

Example 2. A distance of 463 km is exactly 463 ÷ 1.852 = 250 nautical miles, because 250 × 1.852 = 463.

Example 3. A ship making 20 knots covers 20 nautical miles every hour, or 20 × 1.852 = 37.04 km each hour.

Kilometers to nautical miles conversion table

Common mistakes

• Mixing up the two miles. A nautical mile (1.852 km) is about 15% longer than a statute mile (1.609344 km). The kilometers to miles converter is the right tool for road distances.
• Saying knots per hour. A knot already means one nautical mile per hour, so speed in knots is never divided by time again.
• Using degrees of longitude. The one-minute rule works along a meridian (latitude). A minute of longitude shrinks toward the poles.

To work in the opposite direction, use the nautical miles to kilometers converter.