Speed Converter
Convert km/h, mph, meters per second, knots and feet per second.
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- Length Converter — Convert units of distance.
- Time Converter — Convert units of time.
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How to use the Speed Converter
The speed converter changes velocities between the units used on roads, at sea, in the air and in science: kilometers per hour, miles per hour, meters per second, feet per second, knots and Mach (the speed of sound at sea level). Enter any speed to see it in every unit.
- 1 Enter the speed and choose its unit.
- 2 Choose the unit to convert to.
- 3 Read the result and all other units.
Example and practical tips
100 km/h = 62.14 mph = 27.78 m/s. A speed of 20 knots is about 37 km/h.
Frequently asked questions
How do I convert km/h to mph?
Multiply by 0.621371. For example, 100 km/h × 0.621371 = 62.14 mph.
What is a knot?
One knot is one nautical mile per hour, about 1.852 km/h, used at sea and in aviation.
What is Mach 1?
Mach 1 is the speed of sound, about 1,225 km/h at sea level in standard conditions. It changes with temperature and altitude.