How to convert mph to km/h
km/h = mph × 1.609344. The scale factor is the source-unit factor divided by the destination-unit factor.
Worked example
A speed of 60 mph converts to 96.56064 km/h.
- Start with 60 mph.
- Multiply 60 by 1.609344.
- Report 96.56064 km/h, rounded to the precision of your original measurement.
Multiply by 1.609344 for the fixed international-mile conversion. This comparison is not a recommendation for a safe or legal driving speed.
Check the reverse conversion
1 km/h = 0.6213711922 mph. Use the kilometer per hour to mile per hour converter to calculate in the opposite direction. This has its own formula and reference table.
Definitions that matter
A knot is one international nautical mile per hour, not one mile per hour. Speed conversion does not calculate acceleration or journey time.
The base unit for this category is m/s. One mph corresponds to 0.44704 mps; one km/h corresponds to 0.2777777778 mps. These definitions explain the relationship rather than relying on a rounded display value.
Sources and precision
Definitions: NIST Guide to the SI. Calculations use double precision; the tool defaults to a readable rounded result, while tables show up to ten significant digits. Displaying more digits does not increase the accuracy of the original measurement.
Read our calculation methodology and content standards, or continue with distance and time units across measurement systems.