Knots ↔ MPH
Convert between knots and miles per hour
Knots ↔ MPH
Quick Facts
- •1 knot = 1.151 mph = 1.852 km/h
- •Hurricane threshold = 64 knots (74 mph)
Knots Explained
A knot is one nautical mile per hour (1.15078 mph). Knots are the standard speed unit in maritime and aviation worldwide. Wind speeds in weather forecasting for marine and aviation purposes are also reported in knots.
Understanding the knots ↔ mph
A knot is one nautical mile per hour. A nautical mile is 1,852 meters, a little longer than a land mile of 1,609 meters, so one knot equals about 1.151 mph. Boats, aircraft and weather forecasts use knots because a nautical mile matches one minute of latitude, which makes chart navigation simple. To get mph, multiply knots by 1.151. To go back, divide mph by 1.151.
Worked examples
How fast is 25 knots in mph?
- 1One knot is 1.15078 mph.
- 2Multiply: 25 × 1.15078 = 28.77.
- 3For km/h, multiply knots by 1.852: 25 × 1.852 = 46.3 km/h.
25 knots is about 28.8 mph, or 46.3 km/h. That is a fast cruise for a sport boat and a strong breeze on the Beaufort scale.
How fast is 480 knots in mph (a typical jet cruise)?
- 1Multiply the airspeed by 1.15078: 480 × 1.15078 = 552.37.
- 2Round for everyday use: about 552 mph.
480 knots is roughly 552 mph, or about 889 km/h. Ground speed can be higher or lower depending on the wind.
A car is doing 65 mph. What is that in knots?
- 1Divide mph by 1.15078: 65 ÷ 1.15078 = 56.48.
65 mph is about 56.5 knots.
Knots to mph and km/h reference table
Common speeds for boats, wind and aircraft.
| Knots | mph | km/h | Typical example |
|---|---|---|---|
| 5 | 5.75 | 9.26 | Harbour speed limit |
| 10 | 11.51 | 18.52 | Sailboat cruising |
| 15 | 17.26 | 27.78 | Fresh breeze |
| 20 | 23.02 | 37.04 | Ferry or trawler |
| 25 | 28.77 | 46.30 | Sport boat cruise |
| 30 | 34.52 | 55.56 | Planing speedboat |
| 32 | 36.82 | 59.26 | Fast patrol boat |
| 34 | 39.13 | 62.97 | Gale force wind begins |
| 50 | 57.54 | 92.60 | Racing powerboat |
| 64 | 73.65 | 118.53 | Hurricane force wind begins |
| 100 | 115.08 | 185.20 | Light aircraft cruise |
| 250 | 287.70 | 463.00 | Speed limit below 10,000 ft (US) |
| 480 | 552.37 | 888.96 | Airliner cruise |
Practical tips
- •Weather apps often let you switch wind units. Pick knots if you sail so forecasts match your charts.
- •Airspeed in knots is not ground speed. A headwind lowers how fast you actually cover ground.
Frequently asked questions
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This calculator is for educational and reference purposes only. Always verify critical calculations independently.