How many kilometers per hour are in 1 mile per hour?

1 mile per hour equals 1.60934 km/h.

How do I convert kilometers per hour back to miles per hour?

Use the reverse converter: 1 kilometer per hour equals 0.621371 mph.

Yes. It uses the exact SI/NIST definitions of each unit and shows up to 6 significant digits.

To convert miles per hour to kilometers per hour, multiply the value by 1.609344.

km/h = mph × 1.609344

40 mph × 1.609344 = 64.37 km/h

Mile Per Hour (mph): Used for road speed limits in the US and UK. Exactly 0.44704 metres per second.
Kilometer Per Hour (km/h): Used for road speed limits and vehicle speeds in most countries.

How do I convert miles per hour to kilometers per hour?: To convert miles per hour to kilometers per hour, multiply the value by 1.609344.
How many kilometers per hour are in 1 mile per hour?: 1 mile per hour equals 1.60934 km/h.
How many kilometers per hour are in 10 miles per hour?: 10 mph equals 16.0934 km/h.
How do I convert kilometers per hour back to miles per hour?: Use the reverse converter: 1 kilometer per hour equals 0.621371 mph.
Is this converter accurate?: Yes. It uses the exact SI/NIST definitions of each unit and shows up to 6 significant digits.