Miles/hour to Kilometers/hour Converter
Convert miles/hour to kilometers/hour instantly. Exact factor: 1 mph = 1.609 km/h.
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Convert miles/hour to kilometers/hour
The exact conversion factor is 1 mph = 1.609 km/h. Type any value and the result updates instantly; the math is shown beneath the board.
Worked by hand
Multiply the miles/hour value by 1.609 to get kilometers/hour.
Worked example
- Take 1 mph
- multiply by 1.609
- the result is 1.609 km/h
How to use it
- Enter your miles/hour
- Read the kilometers/hour result
- Check the factor line to verify by hand
Frequently asked questions
How many kilometers/hour are in one miles/hour?
Exactly 1.609 km/h, by the SI/NIST definition.
How do I convert kilometers/hour back to miles/hour?
Divide by 1.609 — or use the full converter where both directions are one click.
Is this rounding or exact?
The factor is exact; only the displayed decimals are rounded.