Speed Distance Time Calculator
Work out speed, distance or time from the other two.
The three linked quantities
Speed, distance and time are bound together — speed is distance over time — so given any two you can find the third. This calculates whichever you need: the time a journey takes at a given speed, the distance covered, or the average speed of a trip.
Enter two of speed, distance and time to get the third.
Mind the units
The maths is straightforward; the mistakes are almost always about units. Speed in miles per hour with a distance in kilometres, or a time in minutes where the speed is per hour, gives a nonsense answer unless the units are made consistent first. Keeping the units aligned — matching the distance unit to the speed, and the time unit to the speed's per-hour or per-second basis — is the whole discipline of getting these right.
Questions & answers
What can it calculate?
Any of speed, distance or time from the other two — for example the time a journey takes at a given speed.
What is the common mistake?
Mismatched units — a speed per hour with a time in minutes, say. Keeping units consistent is what makes the answer correct.
Is anything uploaded?
No. The calculation happens in your browser.