Contents
How the mph to km/h converter works
Type a speed in either field and the other value changes at once. You can also select knots, metres per second or feet per second without losing the speed you entered.
The exact conversion factor
An international mile is exactly 1,609.344 metres, so one mile per hour equals exactly 1.609344 kilometres per hour:
For the reverse direction, divide km/h by 1.609344. The converter keeps the full factor and displays up to six decimal places.
Useful road-speed examples
- 30 mph = 48.28032 km/h. This is close to 50 km/h.
- 60 mph = 96.56064 km/h. A familiar motorway value is just under 100 km/h.
- 70 mph = 112.65408 km/h.
- 100 km/h = 62.137119 mph.
What the conversion does not change
The calculation changes only the unit. It does not correct a speedometer, choose a safe speed or account for wind, current and road conditions.
mph uses the statute mile. A knot is based on the longer nautical mile, so mph and knots are not interchangeable even though both contain “per hour”.
Questions about mph and km/h
The key points are the exact factor, the reverse operation and sensible rounding.
How many km/h is 1 mph?
Exactly 1.609344 km/h.
How do I convert mph to km/h?
Multiply mph by 1.609344.
How do I convert km/h to mph?
Divide km/h by 1.609344.
Is 60 mph the same as 100 km/h?
Not exactly. 60 mph is 96.56064 km/h, while 100 km/h is about 62.137119 mph.
Should I round before calculating?
No. Keep the exact factor and round only the displayed result.
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