Knots to MPH
A knot is one nautical mile per hour, used for sea and air travel because nautical miles align with degrees of latitude. A statute mile (the everyday US mile) is shorter, so the same speed in knots is a larger number in mph:
1 knot ≈ 1.15078 mph
1 mph ≈ 0.86898 knots
The exact factor is mph = knots × (1852 / 1609.344) — the ratio of nautical to statute mile lengths.
How to use
Enter a speed in knots. The mph equivalent appears instantly.
Reference values
| Knots | mph | |---|---| | 1 | 1.15 | | 5 | 5.75 | | 10 | 11.51 | | 15 | 17.26 | | 25 | 28.77 | | 50 | 57.54 | | 100 | 115.08 | | 500 (small jet cruise) | 575.39 |
When does this come up?
- Sailing and boating — boat speeds are almost always given in knots.
- Aviation — pilots use knots for airspeed and ground speed.
- Weather reports — wind speed at sea, hurricane categories.
- Maritime navigation — nautical charts and GPS readings.
FAQ
What about km/h?
1 knot ≈ 1.852 km/h (exact). To get km/h, multiply knots by 1.852.
Why are knots called "knots"?
Sailors historically measured ship speed by trailing a knotted rope behind the boat for a fixed time and counting the knots that paid out. One knot per unit time → one nautical mile per hour. The name stuck.
Is "1.15078" exact?
It's a rounded approximation. The exact factor is 1852/1609.344 = 1.1507794... For most everyday use, 1.15078 is plenty precise.