Convert speeds between kilometers per hour, miles per hour, meters per second and knots.
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60 mph is exactly 96.56064 km/h, and 100 km/h is about 62.13711922 mph. In SI units, 10 m/s is exactly 36 km/h, and at sea 20 knots is 37.04 km/h.
Every speed is converted through meters per second using exact definitions: a mile is 1,609.344 m, so 1 mph is exactly 1.609344 km/h, and a nautical mile is 1,852 m, so 1 knot is exactly 1.852 km/h. Multiplying m/s by 3.6 gives km/h.
Speed limits in countries using miles and kilometers are set as round numbers in each system rather than exact conversions, so a 100 km/h sign and a 60 mph sign are close but not identical. The tool converts units only; for minutes per kilometer or per mile, use the Pace Calculator.
A mile per hour is exactly 1.609344 km/h, because the mile is exactly 1,609.344 m. That makes 60 mph exactly 96.56064 km/h, and 100 km/h about 62.13711922 mph. Speed limits in countries using miles and kilometers are chosen as round numbers in each system rather than exact conversions, so a 100 km/h sign and a 60 mph sign are close but not the same. Use the Pace Calculator if you need minutes per kilometer or per mile.
Meters per second is the SI unit used in physics and weather data. Multiply by 3.6 to get km/h, so 10 m/s is exactly 36 km/h, which is a fresh breeze or a fast sprint. The speed of sound in dry air at about 20 °C is roughly 343 m/s, or 1,234.8 km/h; it changes with temperature, so treat that figure as a typical value, not a constant. Wind forecasts may use m/s, km/h, mph or knots depending on the country and the service.
A knot is one nautical mile per hour, and a nautical mile is exactly 1,852 m, so 1 knot is exactly 1.852 km/h and about 1.15077945 mph. A boat travelling at 20 knots is moving at 37.04 km/h. Aviation and marine charts use nautical miles because one nautical mile corresponds approximately to one minute of latitude. Aircraft airspeed indicators show indicated airspeed, which differs from speed over the ground when there is wind or at high altitude.
| Input | Result |
|---|---|
100 km/h → mph | 62.13711922 |
60 mph → km/h | 96.56064 |
10 m/s → km/h | 36 |
20 knot → km/h | 37.04 |
1 knot → mph | 1.15077945 |
343 m/s → km/h | 1,234.8 |
One nautical mile per hour. A nautical mile is exactly 1,852 m, so 1 knot is 1.852 km/h and about 1.15077945 mph, and a boat doing 20 knots is moving at 37.04 km/h. Marine and aviation charts use nautical miles because one nautical mile corresponds roughly to one minute of latitude.
It is the SI unit used in physics and weather data, and multiplying by 3.6 gives km/h. So 10 m/s is exactly 36 km/h, about the speed of a fresh breeze or a fast sprint. Wind forecasts may use m/s, km/h, mph or knots depending on the country and the service.
No. In dry air at about 20 °C it is roughly 343 m/s, which is 1,234.8 km/h, but it changes with temperature, so treat that as a typical value rather than a constant. Aircraft airspeed indicators also show indicated airspeed, which differs from speed over the ground in wind or at high altitude.