All tools / Unit Converter40 mph to kmh40 mph = 64.37376 kmhFormula1 mph = 1.609344 kmh, so 40 × 1.609344 = 64.37376Need another value? Use the full Unit ConverterOther mph → kmh conversions1 mph → kmh2 mph → kmh3 mph → kmh4 mph → kmh5 mph → kmh6 mph → kmhReverse conversion40 kmh → mphRelated conversions1 kmh → mph1 mps → kmh1 knots → kmh1 mph → mps1 knots → mph