Speed & Pace Converter
Convert any speed between kilometres per hour, miles per hour, metres per second and knots — and into the runner’s language of minutes per kilometre and per mile, and back again.
Your numbers
Result
How it works
Speed conversions are multiplications by fixed constants: mph to km/h is ×1.60934, m/s to km/h is ×3.6, knots to km/h is ×1.852. Pace is the odd one out because it inverts the quantity — pace is time per distance, so converting needs a division (60 ÷ minutes-per-km gives km/h), which is why doubling pace and doubling speed are not the same thing and why a 30-second pace improvement means more at fast paces than slow ones.
The m/s column is the scientist’s unit and the sprinter’s: a 10-second 100 m is run at an average of 10 m/s, which this page will tell you is 36 km/h — slower than it feels, and faster than any human can sustain for a second hundred metres.
Good practice & limits
- For mental maths: mph → km/h, add half and a bit (×1.6 is close enough at road speeds).
- When a training plan gives pace and your watch shows speed, convert once and write it on the plan.
- Knots and mph are not interchangeable — at sea the difference is 15%, and it matters.