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Nautical Miles to Kilometers Converter

Convert nautical miles to kilometers instantly, with a reference table for flight distances, sea passages and territorial limits.

Nautical Miles to KM Converter

1 nmi = 1.852 km

Multiply nautical miles by 1.852 to get kilometers.

The link carries the values you entered, so whoever opens it sees the same result. Nothing is stored on our side — the numbers travel in the link itself.

Nautical miles to kilometers reference table

The conversions people look up most often, rounded to 4 decimal places.

Common nautical miles to kilometers conversions
Nautical mile (nmi)Kilometer (km)
1 nmi1.852 km
3 nmi5.556 km
10 nmi18.52 km
12 nmi22.224 km
20 nmi37.04 km
50 nmi92.6 km
100 nmi185.2 km
200 nmi370.4 km
500 nmi926 km
1,000 nmi1,852 km
2,000 nmi3,704 km
3,000 nmi5,556 km
5,000 nmi9,260 km

The nautical miles people look up most

1 nmi = 1.852 km
One minute of latitude - the definition the unit was built from, not a factor anyone chose.
3 nmi = 5.556 km
The old limit of territorial waters, said to be a cannon shot from shore.
12 nmi = 22.224 km
The modern territorial sea limit under the Law of the Sea convention.
200 nmi = 370.4 km
The exclusive economic zone, which is why fishing disputes are argued in this unit.
3,000 nmi = 5,556 km
Roughly a North Atlantic crossing on a direct route.

How the nautical miles to km calculation works

A nautical mile is exactly 1.852 kilometers:

kilometers = nautical miles × 1.852

Unlike the statute mile, this one was chosen for a reason. A nautical mile is one minute of arc of latitude — one sixtieth of a degree — measured along a meridian. That makes it the only distance unit that maps directly onto a chart: one minute of latitude is one nautical mile, anywhere on Earth.

Because the planet is not a perfect sphere, the real arc-minute varies from about 1,843 m at the equator to 1,862 m at the poles. The 1,852 m figure was fixed by international agreement in 1929 as a round average, so the modern definition is exact and the geometric origin is now an approximation of it.

A nautical mile is about 15% longer than a statute mile: 1 nmi = 1.15078 statute miles.

Where it is still the working unit:

  • Aviation. Flight distances, navigation and separation are all in nautical miles. A 3,000 nmi leg is 5,556 km. Speeds are in knots — one knot is one nautical mile per hour.
  • Maritime law. Territorial waters extend 12 nmi (22.2 km) from the coast, and an exclusive economic zone reaches 200 nmi (370.4 km). These figures are defined in nautical miles, so their kilometre equivalents are always the converted number.
  • Charts. Distance is read off the latitude scale at the side of the chart, never the longitude scale at the top — longitude minutes shrink toward the poles.

For a rough conversion, add 85% to the nautical miles.

Frequently asked questions

Why do ships and aircraft not use kilometres?

Because a nautical mile is one minute of latitude, so distance and angle share a unit on a chart. A navigator who measures forty minutes of latitude has measured forty nautical miles, with no conversion in between. That property is worth more at sea than agreement with the metric system ashore.

How far away is the horizon at sea?

About two and a half nautical miles from eye level in a small boat, and considerably further from a ship bridge, because the distance grows with the square root of height. Spotting another vessel extends it further still, since its mast appears before its hull - which is why ships carried a crow nest.

What is the 200-mile limit?

The exclusive economic zone: 200 nautical miles from the coast, within which a state controls fishing and seabed resources under the Law of the Sea convention. Territorial waters, where full sovereignty applies, reach only 12 nautical miles, which is why the two numbers turn up in quite different disputes.

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Further reading