Convert between miles per hour, kilometers per hour, knots, and meters per second. Free online speed converter.
A speed converter transforms measurements between different units of velocity, including kilometers per hour (km/h), miles per hour (mph), meters per second (m/s), feet per second (ft/s), and knots. Whether you're comparing vehicle speeds, understanding wind speeds in weather reports, or working with physics problems, accurate speed conversions are essential.
Different countries and fields use different speed units. Most of the world uses km/h for road speeds, while the US and UK use mph. Aviation and maritime industries use knots (nautical miles per hour), and scientific work typically uses meters per second. Being able to convert between these units helps you understand speed measurements in any context.
A highway speed limit of 120 km/h equals 74.56 mph. The speed of sound at sea level is approximately 343 m/s, which equals 1,235 km/h or 767 mph. A commercial jet cruising at 500 knots travels at 926 km/h or 575 mph.