Convert speeds between mph, km/h, meters per second, feet per second and knots, with running pace.
Kilometers per hour
km/h
The same speed in different units
Miles per hour
mph
Meters per second
m/s
Feet per second
ft/s
Knots
knots
Equivalent pace
Show the working
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Formula
1 mph = 1.609344 km/h (exact)1 m/s = 3.6 km/h1 knot = 1 nmi/h = 1.852 km/h1 ft/s = 0.3048 m/s
How it works
Every speed unit is a length unit divided by a time unit, so the conversions follow from the exact length definitions: a mile is 1.609344 km, so 60 mph is 96.56 km/h. To go from m/s to km/h multiply by 3.6 (3,600 seconds per hour ÷ 1,000 meters per kilometer).
Knots — nautical miles per hour — are used at sea and in aviation because a nautical mile corresponds to one minute of latitude, which makes chart navigation simple. One knot is about 1.15 mph.
Runners and walkers often think in pace rather than speed, so the converter also shows the time needed per kilometer and per mile at the entered speed.
Frequently asked questions
What is 100 km/h in mph?
About 62.1 mph.
How fast is the speed of sound?
About 343 m/s (1,235 km/h or 767 mph) in dry air at 20 °C. It varies with temperature.