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Speed, distance and time.
The speed calculator relates speed, distance and time. Given any two of them it finds the third, so you can work out average speed, how far you will travel, or how long a journey will take.
It uses average speed over the whole trip and assumes consistent units — kilometres for distance and hours for time, giving speed in kilometres per hour.
To convert km/h to metres per second divide by 3.6; the calculator shows the m/s equivalent when solving for speed.
Convert the minutes to a decimal fraction of an hour: 30 minutes is 0.5, so enter 1.5 hours. 15 minutes is 0.25, and 45 minutes is 0.75.
It is average speed over the full distance and time you enter. Actual speed at any moment can be higher or lower.
Yes — the maths is unit-agnostic as long as you are consistent. Enter distance in miles and time in hours and the speed will be in miles per hour, though the labels will still read km.
The three quantities are linked by one equation, so any two determine the third. Entering two and leaving one blank tells the calculator which to solve for.