How to Convert Knots to MPH
A knot is a unit of speed equal to one nautical mile per hour. It's the standard unit for maritime navigation and aviation. Miles per hour (mph) is the common land speed unit in the US. Understanding the conversion is useful for sailors, pilots, and anyone watching weather reports that give wind speed in knots.
The conversion factor is 1 knot = 1.15078 mph.
The Conversion Formula
MPH = Knots Γ 1.15078
Going the other direction:
Knots = MPH Γ· 1.15078
Step-by-Step Example
A weather report says winds are at 25 knots. What is that in mph?
- 25 Γ 1.15078 = 28.77 mph (approximately 29 mph)
Reference Table
| Knots | MPH | Context |
|---|---|---|
| 5 kts | 5.75 mph | Light breeze |
| 10 kts | 11.51 mph | Gentle breeze |
| 20 kts | 23.02 mph | Fresh breeze |
| 30 kts | 34.52 mph | Near gale |
| 50 kts | 57.54 mph | Storm |
| 100 kts | 115.08 mph | Hurricane-force |
Why Knots Are Used in Navigation
A knot is based on the nautical mile, which is defined as one minute of arc of latitudeβabout 1.852 km. This makes nautical charts and navigation calculations far simpler than using miles, since latitude lines directly translate to distance. One degree of latitude = 60 nautical miles.
Aircraft and ships use knots because their routes follow great circles over Earth's curved surface, where nautical miles simplify the math.
Use our knots-to-mph calculator for any speed conversion.