Unit converter
Nautical miles to kilometres.
Convert nmi to km and km to nmi. Type in either box and the other follows. A nautical mile is 1852 m exactly, defined so one minute of latitude is one nautical mile — it is not a rounded version of the land mile.
| nmi | km |
|---|---|
| 1 nmi | 1.852 km |
| 2 nmi | 3.704 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 |
- Conversion goes through m in both directions, so neither figure is rounded on the way.
Definitions
- The nautical mile is exactly 1852 m, defined for navigation rather than derived from the yard. One knot is one nautical mile per hour.
- The kilometre is a thousand metres, and the unit road distances are signed in almost everywhere except the UK and the US.
- This conversion is exact by definition. 1 nmi = 1.852 km.
- The metre is SI; every imperial and US customary length here is defined exactly in terms of it by the 1959 international yard and pound agreement.
How it works
One direction multiplies and the other divides by the same number, so nothing is lost by going back and forth.
The value passes through m, the unit every other length & distance unit on the site is defined against, rather than a number written into this page on its own. That is why the figure here, the figure in the table above and the general length & distance converter always agree.
Display precision limits significant figures rather than decimal places, because one fixed number of decimals is useless across a range this wide. Very large and very small results switch to scientific notation with a proper superscript exponent. The editable box always holds a plain number at full working precision, so you can carry on from either side.
Common questions this answers: how many kilometres in a nautical mile (1.852), how many nautical miles in a kilometre (0.539957), and what 100 nmi is in kilometres (185.2 km).
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