How to Calculate Miles per Hour.

How to Calculate Miles per Hour.

Since one kilometer per hour is equal to 1.609344 miles per hour, [1] that’s the conversion ratio used in the formula. For example, here’s how to convert 5 kilometers per hour to miles per hour using the formula above. mph = (5 km/h ÷ 1.609344) = 3.106856 mph. Kilometers per hour and miles per hour are both units used to measure speed .