Convert between mph and km/h for driving, sports, and travel.
What this calculator does
1 mph = 1.60934 km/h.
How it works
Speed limits: US uses mph, Europe uses km/h.
When to use this calculator
This calculator is most useful when precision matters: technical specifications, recipe scaling, scientific measurements, or any context where an approximate conversion introduces real risk.
Common mistakes
A frequent mistake is converting in the wrong direction — multiplying where the formula requires division, or vice versa. Always verify the direction of conversion: are you converting from the smaller or larger unit?
Real-world scenarios
A UK architect receives a specification from a US client with dimensions in feet and inches. Converting each measurement to millimetres with precision ensures the drawings are accurate — approximate mental conversion would introduce errors that compound across multiple linked dimensions.