Speed Converter

Convert speed between miles per hour, kilometers per hour, meters per second, knots, feet per second and Mach.

How to use the Speed Converter

  1. Type the value you want to convert in the first box.
  2. Choose the unit you are converting from and the unit you want to convert to.
  3. Read the result instantly. Use the swap button to reverse the direction, or copy the result with one click.

Popular speed conversions

ConversionResultFormula
Kilometers per hour to miles per hour1 km/h = 0.621371 mphmiles per hour = kilometers per hour × 0.62137119
Miles per hour to kilometers per hour1 mph = 1.60934 km/hkilometers per hour = miles per hour × 1.609344
Meters per second to kilometers per hour1 m/s = 3.6 km/hkilometers per hour = meters per second × 3.6
Kilometers per hour to meters per second1 km/h = 0.277778 m/smeters per second = kilometers per hour ÷ 3.6
Knots to miles per hour1 kn = 1.15078 mphmiles per hour = knots × 1.1507794
Miles per hour to knots1 mph = 0.868976 knknots = miles per hour × 0.86897624
Knots to kilometers per hour1 kn = 1.852 km/hkilometers per hour = knots × 1.852
Kilometers per hour to knots1 km/h = 0.539957 knknots = kilometers per hour ÷ 1.852
Meters per second to miles per hour1 m/s = 2.23694 mphmiles per hour = meters per second × 2.2369363
Miles per hour to meters per second1 mph = 0.44704 m/smeters per second = miles per hour × 0.44704
Feet per second to miles per hour1 ft/s = 0.681818 mphmiles per hour = feet per second × 0.68181818
Miles per hour to feet per second1 mph = 1.46667 ft/sfeet per second = miles per hour × 1.4666667
Mach to miles per hour1 Mach = 767.269 mphmiles per hour = Mach × 767.26915
Miles per hour to Mach1 mph = 0.00130332 MachMach = miles per hour × 0.0013033236
Mach to kilometers per hour1 Mach = 1,234.8 km/hkilometers per hour = Mach × 1,234.8
Kilometers per hour to Mach1 km/h = 0.000809848 MachMach = kilometers per hour ÷ 1,234.8

Supported speed units

UnitSymbolEqual to
Meter per secondm/s1 m/s
Kilometer per hourkm/h0.27777778 m/s
Mile per hourmph0.44704 m/s
Knotkn0.51444444 m/s
Foot per secondft/s0.3048 m/s
Foot per minuteft/min0.00508 m/s
Kilometer per secondkm/s1,000 m/s
Centimeter per secondcm/s0.01 m/s
Meter per minutem/min0.016666667 m/s
Mach (sea level, 20 °C)Mach343 m/s
Speed of lightc299,792,458 m/s

Common speed units

Road speeds are given in kilometers per hour in most countries and miles per hour in the United States and United Kingdom. Scientists use meters per second, and ships and aircraft use knots, where one knot is one nautical mile per hour (1.852 km/h).

To convert km/h to m/s, divide by 3.6. To convert mph to km/h, multiply by 1.609344.

About Mach

Mach number is the ratio of a speed to the speed of sound, which changes with air temperature. This converter uses 343 m/s, the speed of sound in dry air at 20 °C. At cruising altitude, where the air is much colder, Mach 1 is closer to 295 m/s.

Frequently asked questions

How do I convert km/h to mph?

Multiply the speed in km/h by 0.621371. For example, 100 km/h is about 62.14 mph.

How fast is one knot?

One knot is one nautical mile per hour, which equals 1.852 km/h or about 1.15078 mph.

How do I convert m/s to km/h?

Multiply by 3.6. For example, 10 m/s equals 36 km/h.

How fast is Mach 1?

Mach 1 is the speed of sound: about 343 m/s (1,235 km/h or 767 mph) in air at 20 °C. It is lower in colder air.

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