Speed Converters
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Metric
meters per second
kilometers per hour
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Imperial / US
miles per hour
feet per second
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Nautical & Aviation
knots
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Scientific
mach
About speed conversions
Speed conversions are needed daily by drivers, pilots, sailors, athletes, and engineers. The most common conversion is between kilometers per hour (km/h), used in most countries, and miles per hour (mph), used primarily in the United States and United Kingdom.
One km/h equals approximately 0.621 mph. Knots, used in aviation and maritime navigation, equal one nautical mile per hour or approximately 1.852 km/h. Meters per second is the SI unit used in scientific contexts.
For reference, the speed of light is approximately 299,792 km/s, and the speed of sound at sea level is approximately 343 m/s or 1,235 km/h.
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