Miles per hour to Kilometres per hour — mph to km/h
Enter a value to convert miles per hour (mph) to kilometres per hour (km/h). Works in your browser with no sign-up.
Miles per hour · mph
Kilometres per hour · km/h
1 mph = 1.609344 km/h
Formula
1 mph = 1.609344 km/h
Multiply the number of miles per hour by 1.609344. For example, 30 mph × 1.609344 = 48.28032 km/h.
Quick Reference — Miles per hour to Kilometres per hour
About Speed Units
Kilometres per hour is the road-speed unit in most countries; the US and UK use miles per hour. Knots (one nautical mile per hour) are used at sea and in aviation. Mach expresses speed as a multiple of the speed of sound, which depends on air temperature; this converter uses 340.3 m/s, the value for the standard atmosphere at sea level (15 °C).
Related Conversions
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FAQ — Miles per hour to Kilometres per hour
How do I convert miles per hour to kilometres per hour?
Multiply the number of miles per hour by 1.609344. For example, 30 mph × 1.609344 = 48.28032 km/h.
How many kilometres per hour are in one mile per hour?
1 mile per hour = 1.609344 km/h (shown to up to 7 significant figures).
What is Mach 1 in km/h?
In the standard atmosphere at sea level (15 °C) the speed of sound is about 340.3 m/s, which is about 1,225 km/h or 761 mph. It is lower in colder air, so at typical airliner cruising altitude it is closer to 1,060 km/h.
Does this converter work offline?
Yes. Once the page has loaded, conversions run entirely in your browser and nothing is sent to a server.