Speed & Velocity Converter
Convert rates of motion between automotive road speeds (mph, km/h), aviation/nautical navigation (knots), scientific SI velocity (m/s), and supersonic physics scales (Mach).
A knot is defined as exactly 1 nautical mile per hour (1.852 km/h or approximately 1.15078 mph). Historically, sailors measured speed by dropping a wooden log attached to a knotted line overboard and counting the knots passing through a mariner's fingers as sand emptied in a 30-second hourglass.
Named after physicist Ernst Mach, Mach 1 is the local speed of sound in a medium. At sea level in dry air at 20°C (68°F), sound travels at approximately 343 m/s (1,235 km/h or 767 mph). At higher cruise altitudes (35,000 ft where temperature drops to -50°C), Mach 1 is roughly 295 m/s (660 mph).