Knots to mph converter
Type a speed in knots, miles per hour, kilometers per hour or meters per second, and see it in all the others, with the Mach number at your altitude.
The speed of sound in the standard atmosphere: 576 knots at 35,000 ft.
Knots to mph and km/h
| Knots | mph | km/h | m/s |
|---|---|---|---|
| 1 kt | 1.2 | 1.9 | 0.5 |
| 5 kt | 5.8 | 9.3 | 2.6 |
| 10 kt | 11.5 | 18.5 | 5.1 |
| 20 kt | 23 | 37 | 10.3 |
| 30 kt | 34.5 | 55.6 | 15.4 |
| 50 kt | 57.5 | 92.6 | 25.7 |
| 100 kt | 115.1 | 185.2 | 51.4 |
| 150 kt | 172.6 | 277.8 | 77.2 |
| 200 kt | 230.2 | 370.4 | 102.9 |
| 300 kt | 345.2 | 555.6 | 154.3 |
| 400 kt | 460.3 | 740.8 | 205.8 |
| 500 kt | 575.4 | 926 | 257.2 |
| 600 kt | 690.5 | 1,111.2 | 308.7 |
How fast airliners go
Typical figures; every aircraft and every flight differs.
| Phase | Knots | mph | km/h |
|---|---|---|---|
| Taxiing to the runway | ~20 | ~23 | ~37 |
| Lifting off (a typical narrowbody) | ~150 | ~173 | ~278 |
| On final approach | ~140 | ~161 | ~259 |
| Below 10,000 ft (US speed limit) | ~250 | ~288 | ~463 |
| Airliner cruise (true airspeed) | ~480 | ~552 | ~889 |
| A strong jet stream | ~150 | ~173 | ~278 |
At 35,000 feet the speed of sound is about 576 knots, so a 480-knot cruise is Mach 0.83. Ground speed is the cruise speed plus or minus the wind, which is why the same route can be an hour quicker one way: our post on why flying east is faster explains.
For distances, the nautical miles converter does the same job; for why aviation sticks with these units, read why pilots use knots.
Questions
How do I convert knots to mph?
Multiply by 1.15078. A knot is one nautical mile an hour, and a nautical mile is 1,852 meters, a little longer than a statute mile's 1,609 meters. So 100 knots is about 115 mph.
How do I convert knots to km/h?
Multiply by 1.852, exactly. 100 knots is 185.2 km/h.
Why do planes and ships use knots?
Because the nautical mile is tied to the shape of the Earth: it was originally one minute of latitude, so distances on a chart and speeds in knots fit together neatly for navigation. Ships measured speed by counting knots on a rope paid out behind them, which is where the name comes from.
What is Mach?
Speed as a fraction of the speed of sound, which falls as the air gets colder with height. In the standard atmosphere it's about 661 knots at sea level and about 576 knots at 35,000 feet, so the same speed is a higher Mach number up high. Airliners cruise at around Mach 0.78 to 0.85.
Further reading
- Why pilots use knots and nautical milesA nautical mile was one minute of latitude, and a knot is one nautical mile an hour. Where the units come from, why aviation kept them, and how they convert.
- Why planes cruise at 35,000 feetAirliners cruise around 35,000 feet because thin air means less drag and better fuel economy, while still giving enough lift. Why not higher, and why odd and even levels.
- Why flying east is faster than flying westEastbound flights ride the jet stream; westbound ones fight it. How strong it is, how much time it can save, and why it isn't the Earth's spin.
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