Speed Calculator
Calculate speed from distance and time, in m/s, km/h, and mph.
Try an example
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About this calculator
How This Speed Calculator Works
Enter a distance and a time, and the calculator returns speed in meters per second, then automatically converts it to kilometers per hour and miles per hour.
The Formula
v = d ÷ t — speed equals distance divided by time. This calculates average speed over the distance and time given, not instantaneous speed at any single moment.
Worked Example
Usain Bolt's 100m world record of 9.58 seconds works out to 10.44 m/s — about 37.6 km/h or 23.4 mph, sustained over the full sprint.
Worked example
100 meters covered in 10 seconds is 10 m/s — that's 36 km/h, or about 22.4 mph.
Frequently asked questions
What's the formula for speed?
Speed equals distance divided by time (v = d/t).
How do I convert m/s to km/h?
Multiply by 3.6 — this calculator does the conversion automatically alongside mph.
Does this calculate average or instantaneous speed?
Average speed over the given distance and time — it doesn't account for acceleration or changes in speed along the way.
What's the difference between speed and velocity?
Speed is just magnitude (how fast); velocity also includes direction. This calculator handles speed only.