Update your browser or use a current version of Chrome, Edge, Firefox or Safari.
Compare common road, running, scientific and nautical speed units from a single value.
Speeds are normalized through meters per second. One mile per hour is exactly 0.44704 meters per second.
Example formula: miles per hour × 1.609344 = kilometers per hour
The conversion engine uses standardized constants and keeps calculation precision separate from display formatting. Your entered values stay in this browser and are not added to the URL or sent to the server.
The speed of sound changes with temperature and other conditions, so a context-free Mach conversion would imply misleading precision.
One knot is one nautical mile per hour, exactly 1.852 km/h.