Free mph to km/h calculator

miles per hour to kilometers per hour converter

Convert road, running, cycling, and wind speeds from miles per hour to kilometers per hour.

Updated July 20, 2026 Method and assumptions shown below

Convert miles per hour to kilometers per hour

Enter any value to calculate the result instantly.

miles per hour to kilometers per hour formula

Multiply mph by exactly 1.609344. Both units use one hour, so only the mile-to-kilometer distance factor changes.

km/h = mph x 1.609344

Conversion table

Use these reference values for a quick comparison. The calculator above accepts positive, negative, decimal, and large values when they are meaningful for the quantity.

miles per hourkilometers per hour
10 mph16.09344 km/h
20 mph32.18688 km/h
30 mph48.28032 km/h
50 mph80.4672 km/h
60 mph96.56064 km/h
75 mph120.7008 km/h

How to use this converter

Enter the source measurement in the first field. CalUnit applies the displayed formula and updates the destination value immediately. You can use decimals and negative values, copy the result into your work, and compare it with the reference table. Keep the original unit beside the starting measurement so another reader can verify the calculation. For a different unit pair, open the complete speed conversion guide or the multi-unit speed converter.

When this conversion is useful

Use the table to understand foreign road signs or fitness paces, but do not rely on a calculator while driving.

Accuracy and rounding

The unit factor is exact. Round to a sensible whole number for road speeds and retain decimals for scientific calculations when supported by the source reading.

Standards references

CalUnit checks physical unit relationships against authoritative measurement references. See the NIST Guide to the SI conversion factors and the BIPM SI Brochure. Regional cooking measures and digital storage conventions are identified separately because their names can represent more than one definition.