💨
Speed Converter
Convert between mph, km/h, m/s, knots, and Mach number.
About This Calculator
A knot (nautical mile per hour) dates to sailors measuring ship speed with a knotted rope thrown overboard. The speed of sound (Mach 1) at sea level is 340.3 m/s (761 mph) — temperature-dependent. Chuck Yeager first broke the sound barrier at 807 mph on October 14, 1947.