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Convert km/h, mph, m/s, knots, ft/s and more.
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Convert between common speed units used worldwide. Most countries use km/h, while the US uses mph.
Speed describes how fast an object covers a distance, and every industry expresses it differently. Pilots use knots, drivers use kilometers or miles per hour, runners often use minutes per kilometer, and physicists use meters per second. Our speed converter bridges all of these so you can read a foreign weather report or compare race results across regions.
Meters per second (m/s) is the SI unit used in physics. Kilometers per hour (km/h) is the everyday metric road speed unit. Miles per hour (mph) dominates road traffic in the US and UK. Knots (nautical miles per hour) are standard in aviation and marine navigation. The Mach number expresses speed relative to the local speed of sound (Mach 1 ~ 343 m/s at sea level) and is used for supersonic aircraft.
Type your value, pick the unit you have, pick the unit you want. The converter does the multiplication and division in your browser. There are no API calls and no usage limits.
1 km/h equals 0.62137 mph. 1 mph equals 1.609 km/h. 1 knot equals 1.852 km/h or 1.15078 mph. Light travels at 299,792,458 m/s in vacuum — type that into the converter and choose km/h to see why nothing macroscopic comes close.
Because one knot equals one nautical mile per hour, and one nautical mile equals one arc-minute along a great circle of the Earth. Navigators can translate knots into latitude changes mentally.
Conversions use exact constants (for example 1 mile = 1609.344 m exactly) and double-precision arithmetic, so the result is accurate to about 15 significant digits.
The current tool focuses on direct unit conversions. To convert a running pace, divide 60 by the minutes-per-kilometer pace to get km/h, then convert further if needed.
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