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Conversion Formula:
Convert Mile per hour to Kilometer per hour (mph to km/h) instantly with accurate, readable results.
Convert kilometers per hour, miles per hour, meters per second, and other units with our Speed Unit Converter. Great for travel, physics, sports, and navigation, this fast and easy tool helps you convert speed units instantly.
Mile per hour (mph) — an imperial and US customary unit of speed
It is defined as a speed of one international mile traveled in one hour; since 1 mile = 1609.344 meters exactly, 1 mph = 0.44704 meters per second exactly. Used mainly in the United States, United Kingdom, and some other countries for road speed limits, vehicle speeds, wind speeds, transport, aviation contexts, and everyday speed measurements.
- Symbol: mph, mi/h
- System: Imperial and US customary unit for speed
- Exact relations: 1 mph = 1 mi ÷ 1 h = 5280 ft/h = 0.44704 m/s
- Metric equivalents: 1 mph = 1.609344 km/h ≈ 0.868976 kn ≈ 1.46667 ft/s
- Typical examples: city speed limits may be 25–35 mph; highway speeds may be 55–75 mph; a strong wind may be 30 mph.
Kilometer per hour (km/h) — a metric unit of speed
It is defined as a speed of one kilometer traveled in one hour. Used worldwide for road speed limits, vehicle speeds, cycling, running, weather reports, transport, travel, and everyday speed measurements.
- Symbol: km/h, kph
- System: Metric unit for speed; based on SI units
- Exact relations: 1 km/h = 1000 m ÷ 3600 s = 5/18 m/s ≈ 0.277778 m/s
- Other speed equivalents: 1 km/h ≈ 0.621371 mph ≈ 0.911344 ft/s ≈ 0.539957 kn
- Typical examples: city speed limits may be 30–50 km/h; highway speeds may be 100–120 km/h; a fast cyclist may ride at 30 km/h.