Knots to MPH Converter
A knot is a unit of speed used primarily in maritime and aviation contexts, defined as one nautical mile per hour. Unlike statute miles (the standard measure of distance in the United States), nautical miles are based on the Earth's circumference and are used in navigation because they relate directly to latitude and longitude. One knot equals approximately 1.15078 miles per hour (mph) or 1.852 kilometers per hour (km/h). This means that a ship traveling at 10 knots is moving at about 11.5 mph or 18.5 km/h. The conversion between knots and mph is straightforward: multiply knots by 1.15078 to get mph, or divide mph by 1.15078 to get knots. Speed measurements in knots are standard in maritime navigation, aviation, and wind measurement. This calculator converts between knots, miles per hour, kilometers per hour, and meters per second instantaneously. Enter a speed in any of the four units and the others update automatically.
Conversion formulas
Knots to mph: mph = knots * 1.15078
Knots to km/h: km/h = knots * 1.852
Knots to m/s: m/s = knots * 0.514444
mph to knots: knots = mph / 1.15078
km/h to knots: knots = km/h / 1.852
m/s to knots: knots = m/s / 0.514444
Beaufort scale with wind speeds
| Beaufort | Description | Knots | MPH | km/h |
|---|---|---|---|---|
| 0 | Calm | <1 | <1 | <2 |
| 1 | Light air | 1-3 | 1-3 | 2-5 |
| 2 | Light breeze | 4-6 | 4-7 | 7-11 |
| 3 | Gentle breeze | 7-10 | 8-12 | 12-19 |
| 4 | Moderate breeze | 11-16 | 13-18 | 20-29 |
| 5 | Fresh breeze | 17-21 | 19-24 | 30-39 |
| 6 | Strong breeze | 22-27 | 25-31 | 40-50 |
| 7 | Near gale | 28-33 | 32-38 | 51-61 |
| 8 | Gale | 34-40 | 39-46 | 62-74 |
| 9 | Strong gale | 41-47 | 47-54 | 75-88 |
| 10 | Storm | 48-55 | 55-63 | 89-102 |
| 11 | Violent storm | 56-63 | 64-73 | 103-117 |
| 12 | Hurricane | >64 | >73 | >117 |
Knots to MPH converter: frequently asked questions
What is a knot?
A knot is a unit of speed equal to one nautical mile per hour. Nautical miles are used in maritime and aviation contexts because they are based on the Earth's circumference. One knot equals 1.15078 miles per hour, or approximately 1.852 kilometers per hour.
Why is it called a knot?
The term 'knot' originates from the practice of measuring a ship's speed using a knotted rope trailed behind the vessel. A log chip attached to the rope would be released, and the number of knots passing over the rail in a fixed time interval would indicate the ship's speed in nautical miles per hour.
Why do ships and planes use knots instead of mph?
Nautical miles and knots are based on the Earth's circumference and latitude divisions, making them ideal for navigation. One nautical mile is approximately one minute of latitude, which simplifies calculations for plotting courses and distances on navigational charts used in maritime and aviation contexts.
How are knots related to the Beaufort scale?
The Beaufort scale measures wind speed on a 0 to 12 scale, with each level having a characteristic effect on the sea and land. Wind speeds on the Beaufort scale are expressed in knots, starting from Calm (less than 1 knot) to Hurricane force (greater than 64 knots).
What is the difference between a nautical mile and a statute mile?
A nautical mile is 1.15078 statute miles (also called a regular or land mile). Nautical miles are used for marine and aeronautical navigation because one nautical mile corresponds approximately to one minute of arc along the Earth's circumference, whereas statute miles are arbitrary distance units used for land-based distance measurements.
Official sources
- International Hydrographic Organization (IHO): Maritime navigation standards.
- NIST Special Publication 330: The International System of Units.
- International Civil Aviation Organization (ICAO): Aviation speed conventions.
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.