11.51 mph
10 knots is:
| 11.51 | miles per hour |
| 18.52 | kilometres per hour |
| 5.14 | metres per second |
Force 3 on the Beaufort scale: gentle breeze. See the force.
Knots to mph and km/h at a glance
| Knots | mph | km/h | m/s |
|---|---|---|---|
| 1 | 1.15 | 1.85 | 0.51 |
| 2 | 2.3 | 3.7 | 1.03 |
| 3 | 3.45 | 5.56 | 1.54 |
| 4 | 4.6 | 7.41 | 2.06 |
| 5 | 5.75 | 9.26 | 2.57 |
| 6 | 6.9 | 11.11 | 3.09 |
| 7 | 8.06 | 12.96 | 3.6 |
| 8 | 9.21 | 14.82 | 4.12 |
| 10 | 11.51 | 18.52 | 5.14 |
| 12 | 13.81 | 22.22 | 6.17 |
| 15 | 17.26 | 27.78 | 7.72 |
| 20 | 23.02 | 37.04 | 10.29 |
| 25 | 28.77 | 46.3 | 12.86 |
| 30 | 34.52 | 55.56 | 15.43 |
| 40 | 46.03 | 74.08 | 20.58 |
| 50 | 57.54 | 92.6 | 25.72 |
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How to use it
Type the speed and pick its unit. The answer shows the other three units to two decimal places, and the Beaufort force if it were a wind speed. The table under the tool gives common boat speeds at a glance.
How it is worked out
A knot is one nautical mile an hour. The international system of units defines the nautical mile as exactly 1,852 metres. So one knot is 1,852 metres an hour, or 1.852 km/h exactly.
A mile, in UK law, is 1,760 yards, and a yard is exactly 0.9144 metres. That makes a mile 1,609.344 metres. Divide 1,852 by 1,609.344 and one knot comes out at 1.1508 mph, to four decimal places.
So to turn knots into mph, multiply by about 1.15. To go back, divide by it. The tool uses the exact figures, so 20 knots shows as 23.02 mph. It isn't rounded to 23.
Why boats use knots
The BIPM says the nautical mile and the knot are used in marine and air navigation, for distance and speed. It also notes that neither has an internationally agreed symbol.
Sources
- BIPM, The International System of Units (SI Brochure, 9th edition), Table 8: 1 nautical mile = 1852 m; 1 knot = 1852/3600 m/s. Read 30 October 2026
- Weights and Measures Act 1985, Schedule 1: mile = 1760 yards; yard = 0.9144 metre. Read 30 October 2026
- Met Office, Beaufort wind force scale, read 30 October 2026
Craig Fearn runs Still & Wake. He writes the guides and journal.