How to convert nautical miles to kilometres
One nautical mile equals 1.852 kilometres, so multiply the number of nautical miles by 1.852:
km = nmi × 1.852
nmi = km ÷ 1.852 (1 km = 0.539957 nmi)
Example: 3 nmi → 3 × 1.852 = 5.556 km.
Going the other way, divide by 1.852, or multiply by 0.539957.
Everyday values
| Nautical miles | Kilometres | For example |
|---|---|---|
| 1 nmi | 1.852 km | one nautical mile |
| 3 nmi | 5.556 km | the old territorial waters limit |
| 12 nmi | 22.224 km | territorial waters today |
| 200 nmi | 370.4 km | exclusive economic zone |
When you need this conversion
Nautical miles are used at sea and in the air because one nautical mile corresponds closely to one minute of latitude, which makes navigation on charts easier. Under the UN Convention on the Law of the Sea, territorial waters extend 12 nautical miles (22.2 km) from the coast and the exclusive economic zone 200 nautical miles (370.4 km).
Nautical mile to kilometre conversion table
| nmi | km | nmi | km |
|---|---|---|---|
| 1 nmi | 1.852 km | 11 nmi | 20.372 km |
| 2 nmi | 3.704 km | 12 nmi | 22.224 km |
| 3 nmi | 5.556 km | 13 nmi | 24.076 km |
| 4 nmi | 7.408 km | 14 nmi | 25.928 km |
| 5 nmi | 9.26 km | 15 nmi | 27.78 km |
| 6 nmi | 11.112 km | 16 nmi | 29.632 km |
| 7 nmi | 12.964 km | 17 nmi | 31.484 km |
| 8 nmi | 14.816 km | 18 nmi | 33.336 km |
| 9 nmi | 16.668 km | 19 nmi | 35.188 km |
| 10 nmi | 18.52 km | 20 nmi | 37.04 km |
About the units
- Nautical mile (nmi): exactly 1,852 metres (international definition of 1929).
- Kilometre (km): 1,000 metres.
Both are units of length. The conversion factor comes from the exact definitions above, so the calculator is exact; results are only rounded for display (up to six significant digits).
Frequently asked questions
How many kilometres are in one nautical mile?
One nautical mile is 1.852 kilometres. One kilometre is 0.539957 nautical miles.
How do I convert nautical miles to kilometres?
Multiply the value in nautical miles by 1.852. To go back, divide by 1.852.
What is 3 nmi in kilometres?
3 nmi = 5.556 km.
What is 12 nmi in kilometres?
12 nmi = 22.224 km.
Sources
- NIST Special Publication 811 (2008), Guide for the Use of the International System of Units (SI), Appendix B: conversion factors.
- NIST Handbook 44 (2024), Appendix C: General tables of units of measurement.
Last reviewed 5 October 2026. Results are estimates; see our disclaimer.