Unit Conversions
Miles Per Hour vs Kilometers Per Hour: Speed Units Explained
June 25, 2025·3 min read
Everything you need to know about converting between mph and kph — the conversion factor, speed limit comparisons, and vehicle speedometer differences.
Speed is measured in miles per hour (mph) in the US and UK, and kilometers per hour (kph or km/h) almost everywhere else. Whether you're renting a car abroad, reading news from another country, or importing a vehicle, knowing how to convert between them is practically useful.
The Conversion Factor
1 mph = 1.60934 km/h. 1 km/h = 0.62137 mph. To convert mph to km/h, multiply by 1.609. To convert km/h to mph, multiply by 0.621 (or divide by 1.609).
Common Speed Limits Compared
- 30 mph = 48 km/h (typical residential limit)
- 60 mph = 97 km/h
- 70 mph = 113 km/h (UK motorway limit)
- 100 km/h = 62 mph (common highway limit outside US)
- 130 km/h = 81 mph (German Autobahn recommended speed)
Sports Speed References
- Usain Bolt's top sprint speed: ~44.7 km/h = 27.8 mph
- Average marathon pace (3:30 finish): ~12 km/h = 7.5 mph
- Cycling speed (recreational): ~20 km/h = 12.4 mph
- Tennis serve (professional): ~200 km/h = 124 mph
- Formula 1 top speed: ~370 km/h = 230 mph