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Speed and Velocity Converter

Convert miles per hour, kilometers per hour, meters per second, knots and mach. Exact factors based on the international mile and the nautical mile.

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Check this before you rely on it. This converter is provided free and without warranty, and its results are not professional advice.

Popular speed conversions

mph to km/hkm/h to mph

Speed unit reference chart

What one of each unit is worth in meters per second, the base unit used for every conversion in this category.

Speed units expressed in meters per second
UnitSymbol1 unit in m/s
miles per hourmph0.44704 m/s
kilometers per hourkm/h0.2777777778 m/s
meters per secondm/s1 m/s
feet per secondft/s0.3048 m/s
knotskn0.5144444444 m/s
machM340.29 m/s
kilometers per secondkm/s1,000 m/s
miles per secondmi/s1,609.344 m/s
speed of lightc299,792,458 m/s

Speed units explained

Miles per hour (mph)

One mile per hour is exactly 0.44704 meters per second. It is the speed unit on US and UK road signs.

Kilometers per hour (km/h)

One kilometer per hour is exactly 1/3.6 meters per second. It is the standard speed unit almost everywhere outside the US and UK.

Meters per second (m/s)

The meter per second is the SI unit of speed and the unit used in physics calculations.

Feet per second (ft/s)

One foot per second is exactly 0.3048 meters per second. It is the customary unit for muzzle velocity, conveyor speed and airflow in the United States.

Knots (kn)

A knot is one nautical mile per hour, or exactly 1.852 km/h. It is the standard speed unit in marine and air navigation.

Mach (M)

Mach 1 is the speed of sound. This converter uses 340.29 m/s, the value at sea level in the International Standard Atmosphere.

Frequently asked questions

What is the base unit of speed?

This converter routes every speed conversion through the meter per second. Converting from one unit to another means converting to meter per seconds first and then out again, which keeps every pair consistent with every other pair.

How accurate are these speed conversions?

Results are shown to 10 significant digits using exact defined factors wherever a unit has one. No rounding is applied beyond that final display step.

All speed conversions

Every speed conversion page on this site, 48 in total.