Nautical miles to km converter
1 nautical mile = 1.852 kilometres. Straight-line distances between cities in nautical miles are also shown by our straight-line distance calculator.
1 nmi = 1.85 km · 1 km = 0.54 nmi
Nautical miles to kilometres table
| Nautical miles | Kilometres |
|---|---|
| 1 nmi | 1.85 km |
| 2 nmi | 3.7 km |
| 5 nmi | 9.26 km |
| 10 nmi | 18.52 km |
| 20 nmi | 37.04 km |
| 50 nmi | 92.6 km |
| 100 nmi | 185.2 km |
| 200 nmi | 370.4 km |
| 500 nmi | 926 km |
| 1,000 nmi | 1,852 km |
Why the nautical mile is exactly 1.852 km
The nautical mile equals one minute of latitude: Earth's polar circumference (~40,007 km) divided by 360 degrees and again by 60 minutes gives ~1.852 km. On a sea chart divided into degrees and minutes, one minute of latitude therefore always equals one nautical mile — the reason navigation still uses it. It was fixed internationally at exactly 1,852 metres in 1929.
Practical anchors: territorial waters extend 12 nmi (22.2 km) off the coast; a sailing day-leg of 40–60 nmi is 74–111 km; the matching speed unit is the knot (1 nmi per hour). Don't confuse it with the shorter statute mile (1.609 km).
Reading distances off a sea chart
Charts are divided into degrees and minutes: one minute of latitude equals one nautical mile, on any chart at any scale — so navigators measure distance with dividers against the latitude scale at the side. Never use the longitude scale: meridians converge towards the poles (at 54° N one minute of longitude is only ~1.09 km).
Frequently asked questions
How many km is a nautical mile?
Exactly 1.852 kilometres. It corresponds to one minute of latitude on the Earth's meridian, which is why sea charts and nautical miles fit together.
Is a nautical mile longer than a statute mile?
Yes: 1.852 km versus 1.609 km — about 15 % longer.
What's the difference between a nautical mile and a knot?
The nautical mile measures distance, the knot measures speed: 1 knot = 1 nautical mile per hour = 1.852 km/h.
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