Speed, Distance & Time Calculator
Find average speed from a distance and a time — in km/h, m/s and mph — with the pace per kilometre.
How fast you went, from how far and how long.
How the speed, distance & time calculator works
Average speed is distance divided by time. Enter the distance in kilometres and the time in hours, minutes and seconds; the calculator converts the time to hours, divides, and shows the result in kilometres per hour, metres per second and miles per hour, plus the pace (minutes per kilometre) that runners and cyclists use.
Average speed hides variation: a trip with stops has a lower average than the cruising speed. For instantaneous speed you need a speedometer or GPS reading at the moment in question.
Formula: speed = distance ÷ time
Worked examples
| Inputs | Average speed | Note |
|---|---|---|
| 100 km in 1 h 15 min | 80 km/h | 80 km/h |
| 10 km in 50 min | 12 km/h | 12 km/h — a 5:00 /km run |
| 42.195 km in 3 h 30 min | 12.06 km/h | a 3:30 marathon |
FAQFrequently asked questions
How do I convert km/h to m/s?
Divide by 3.6 — there are 1,000 m in a kilometre and 3,600 s in an hour. 90 km/h is 25 m/s.
How do I find time from speed and distance?
Rearrange: time = distance ÷ speed. 250 km at 100 km/h takes 2.5 hours. Pin a result, change the inputs and compare.
Is average speed the same as average velocity?
No. Velocity has direction: a lap that ends where it started has zero average velocity but a positive average speed.
What is a knot?
One nautical mile (1,852 m) per hour, about 1.852 km/h. 20 knots is 37 km/h.
Where these figures come from
- NIST — CODATA 2018 fundamental physical constants — G, g₀, R, c
- NIST Special Publication 811 — Guide for the use of the International System of Units — unit conversions
- The Engineering ToolBox — material properties — specific heats, expansion coefficients, densities
- National Physical Laboratory — the UK's national measurement institute
Last checked: September 2026. Constants are the CODATA 2018 values; formulas are the standard textbook forms.