This free speed converter changes miles per hour (mph) into knots (kn) and back again, updating live as you type. It is built for sailing, aviation, and weather reports that quote wind or vessel speed in knots while you think in mph.
How it works
A knot is one nautical mile per hour. Since a statute mile is 1609.344 m and a nautical mile is 1852 m, the converter uses the ratio of those definitions:
- kn = mph × (1609.344 ÷ 1852) = mph × 0.868976242
- mph = kn ÷ 0.868976242
The factor is computed at full floating-point precision, and the conversion is bidirectional — edit either field and the other updates instantly.
Example
A weather forecast gives a wind speed of 30 mph and you want it in knots.
30 × 0.868976242 = 26.07 kn.
| Miles per hour (mph) | Knots (kn) |
|---|---|
| 1 mph | 0.86898 kn |
| 30 mph | 26.0693 kn |
| 60 mph | 52.1386 kn |
| 100 mph | 86.8976 kn |
All calculations run entirely in your browser with no data sent to any server.