Convert Mile per Hour to Kilometer per Hour (mph → km/h)

Converting miles per hour to kilometers per hour is straightforward: multiply by the conversion factor. Follow these three steps to do it by hand or in your head.

1. 1
   Take your value in miles per hour

   Start with the number of miles per hour (mph) you want to convert.
2. 2
   Multiply by 1.609344

   The conversion factor from mph to km/h is 1.609344. Multiply your value by this number.
3. 3
   Read the result in kilometers per hour

   The result is your value in kilometers per hour (km/h).

Multiply the value in miles per hour by 1.609344. For the reverse direction, multiply by 0.621371.

• ✓1 mph = 1.609 km/h = 0.447 m/s.
• ✓Quick convert: mph × 1.6 = km/h.
• ✓UK speeds posted in mph on road signs despite general metrication.

• ✗Reading a UK road sign "50" as km/h — it's mph (= 80 km/h).
• ✗Converting mph to km/h by multiplying by 1.5 instead of 1.609 — 7% error.
• ✗Assuming "mph" and "MPH" differ — capitalisation does not matter.

What is the Mile per Hour?

Miles per hour is the road-speed standard in the United States, the United Kingdom, and several Caribbean countries. American and British road signs, car speedometers, and weather reports use mph. Typical US speed limits are 25 mph (residential), 35–45 mph (urban arterials), 55–65 mph (rural highways), and 65–80 mph (interstates). The UK uses mph despite metric measurement elsewhere — a result of incomplete metrication. Mph derives from the mile (distance) and hour (time): 1 mph ≈ 1.609 km/h ≈ 0.447 m/s. World-class sprinters reach about 27 mph, professional baseball pitchers throw at 90–105 mph, and commercial airliners cruise at 550–600 mph. The unit relates to km/h (1 mph ≈ 1.609 km/h), m/s (1 mph ≈ 0.447 m/s), the knot (1 mph ≈ 0.869 kn), and ft/s (1 mph ≈ 1.467 fps).

• US and UK road speed limits
• US car speedometers
• US baseball pitch speeds

What is the Kilometer per Hour?

Kilometers per hour is the universal road-speed and weather wind-speed unit in 195 countries — every nation outside the United States, the United Kingdom, and a handful of Caribbean territories. Speed limits on European, Asian, Australian, African, and Latin American roads are posted in km/h: typical urban limits are 50 km/h, highway 100–130 km/h. Weather reports give wind speeds in km/h universally. The unit derives directly from the kilometer (distance) and hour (time): 1 km/h ≈ 0.278 m/s. Car speedometers in metric countries display km/h prominently, with smaller mph numbers for travel to the UK. Olympic 100-meter sprints reach 36–37 km/h, urban cyclists travel at 15–25 km/h, and commercial trains in Europe cruise at 200–300 km/h. The unit relates to mph (1 km/h ≈ 0.621 mph), m/s (3.6 km/h = 1 m/s), and the knot (1 km/h ≈ 0.540 kn).

• European and global road speed limits
• Car and motorcycle speedometers
• Weather wind speed reporting (in some regions)