Miles per hour is a unit of speed, expressing the number of international miles covered per hour. Miles per hour is the unit used for speed limits on roads in the United Kingdom, United States and various other nations, where it is commonly abbreviated in everyday use to mph or MPH, although mi/h is sometimes used in technical publications. The Online Conversion Calculator helps to convert Miles per hour to km per hour (mph to km/h) and km/h to mi/h (kilometers/hour to mph (miles/hour) conversion)