How to convert m/s to km/h
km/h = m/s × 3.6. The scale factor is the source-unit factor divided by the destination-unit factor.
Worked example
For a constant or average travel speed of 20 m/s converts to 72 km/h.
- Start with 20 m/s.
- Multiply 20 by 3.6.
- Report 72 km/h, rounded to the precision of your original measurement.
Check the reverse conversion
1 km/h = 0.2777777778 m/s. Use the kilometer per hour to meter per second 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 m/s corresponds to 1 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.