Mile per hour (mph)

Definition

Miles travelled per hour, exactly 1.609344 km/h.

History

Miles per hour grew out of the English mile and the hour as roads and railways spread in the nineteenth century. It equals exactly 1.609344 kilometers per hour.

Where it is used

Miles per hour is the speed unit for road traffic in the United States and United Kingdom, and is common for running pace.

Typical uses include vehicle speed in the US and UK, speed limits, running pace.

Conversion pages

These pages convert mile per hour to or from another unit in speed.

• Mile per hour to kilometer per hour
• Knot to mile per hour

Other Speed units

• Kilometer per hour (km/h)
• Meter per second (m/s)
• Knot (kn)
• Foot per second (ft/s)

Sources

• NIST HB 44 NIST Handbook 44, Appendix C (Tables of Equivalents — international nautical mile); speeds derived from the exact mile, foot and hour · Dataset reviewed Nov 11, 2026