A knot is the speed unit used for boats and aircraft. One knot is one nautical mile per hour. Converting it to everyday units is easy once you know the numbers.
The formulas
- Knots → km/h: multiply by 1.852
- Knots → mph: multiply by 1.15078
- km/h → knots: divide by 1.852
- mph → knots: divide by 1.15078
So 1 knot = 1.852 km/h = 1.151 mph.
Quick conversion table
| Knots | km/h | mph |
|---|---|---|
| 1 | 1.9 | 1.2 |
| 5 | 9.3 | 5.8 |
| 10 | 18.5 | 11.5 |
| 15 | 27.8 | 17.3 |
| 20 | 37.0 | 23.0 |
| 30 | 55.6 | 34.5 |
| 50 | 92.6 | 57.5 |
| 100 | 185.2 | 115.1 |
Why boats use knots
A nautical mile is based on the Earth's geometry (one minute of latitude), which makes knots convenient for navigation on charts. That's why boats and planes stuck with knots while cars moved to km/h and mph.
Measure your own speed in knots
If you're on the water and want your live speed in knots, you don't need to convert anything — use the Boat Speedometer, which shows GPS speed directly in knots (and lets you switch to km/h or mph). It's free and nothing is uploaded.