Speed, Distance & Time Calculator
Solve for speed, distance or time from any two values, with metric, imperial and nautical units plus running pace.
- Speed
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- Distance
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- Time
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- Pace
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min per km / per mile
How it works
Speed, distance and time are three sides of the same equation: speed = distance ÷ time, distance = speed × time, and time = distance ÷ speed. Pick which one you want to solve for, type the other two, and the answer appears as you type — the field you are solving for turns read-only and fills itself in. Drive 120 km in 1.5 hours and the average speed is 80 km/h, or 22.222 m/s, or 49.71 mph.
Units can be mixed freely: give the distance in metres, kilometres, miles, nautical miles, feet or yards, the time in seconds, minutes, hours or days, and the speed in m/s, km/h, mph, knots or ft/s. Everything is converted through SI internally (1 mile = 1609.344 m, 1 nautical mile = 1852 m, 1 knot = 1 nmi/h), so a distance in miles with a time in minutes still gives a clean answer in km/h. The Pace box turns the same result into running or cycling pace — minutes and seconds per kilometre and per mile. Note that this is average speed over the whole journey, not instantaneous speed, and it ignores stops unless you include them in the time. All the arithmetic runs in your browser in plain JavaScript: no numbers are uploaded, there is no sign-up and there are no ads. Copy the result or download it as a text file to keep with a mileage claim or a training log.
Frequently asked questions
How do you calculate speed from distance and time?
Divide the distance by the time: speed = distance ÷ time. Cover 120 kilometres in 1.5 hours and your average speed is 120 ÷ 1.5 = 80 km/h, which is the same as 22.222 m/s, 49.71 mph or 43.197 knots. Leave "Solve for" on Speed, type the distance and the time, and the calculator does the division and all four unit conversions as you type.
Can I mix units, like miles with minutes?
Yes. The distance, time and speed each have their own unit menu, and they are completely independent. You can enter a distance in miles, a time in minutes and read the answer in km/h, or enter nautical miles and hours to get knots. Everything is converted through SI internally using the exact definitions (1 mile = 1609.344 m, 1 nautical mile = 1852 m, 1 knot = 1 nmi/h), so mixed units are just as accurate as matching ones.
Is this average speed or instantaneous speed?
Average speed over the whole journey. The formula divides the total distance by the total time, so any stops, traffic or changes of pace are averaged into the result — if you want the driving-only average, enter only the moving time. It does not model acceleration or instantaneous speed at a given moment; for that, use the acceleration calculator. All the maths runs in your browser, so nothing you type is uploaded or stored.