mph to km/h Converter
Convert speed between miles per hour and kilometres per hour, with m/s and knots. Type in either side.
About this tool
Uses 1 mile = 1.609344 km exactly, 1 km/h = 1/3.6 m/s and 1 knot = 1.852 km/h.
Speed limits, car specifications and treadmill settings use miles per hour in some countries and kilometres per hour in others. Type a speed in mph to see km/h, metres per second and knots, or type km/h to get mph. Both boxes update as you type.
How to use the mph to km/h Converter
- Type a speed in miles per hour, for example 60.
- Read the km/h next to it, and m/s and knots below.
- Or type km/h instead, and the mph updates.
- Use m/s for physics problems and knots for boats and aircraft.
Common speeds
60 mph × 1.609344 = 96.56 km/h. 70 mph is 112.65 km/h, and 120 km/h, the freeway speed limit in South Africa, is 74.56 mph. 100 km/h is 27.78 m/s.
How the conversion works
Both units measure distance per hour, so the conversion is the same as for distance: 1 mile is exactly 1.609344 km. Multiply mph by 1.609344 for km/h, or divide km/h by 1.609344 for mph. Dividing km/h by 3.6 gives metres per second, because an hour has 3 600 seconds and a kilometre 1 000 metres. A knot is one nautical mile (1.852 km) per hour.
Frequently asked questions
What is 100 km/h in mph?
About 62.14 mph.
What is 120 km/h in mph?
About 74.56 mph.
How do I turn km/h into m/s?
Divide by 3.6. For example, 36 km/h is 10 m/s.
What is a knot?
One nautical mile per hour, exactly 1.852 km/h, used at sea and in aviation.