Speed, Distance and Time Calculator
Enter any two of speed, distance and time to get the third. v = d / t. Works in km/h, m/s, mph and knots with a step by step solution.
How speed, distance and time relate
The distance covered at constant speed is the speed multiplied by the time taken: d = v × t. Rearranged, speed is v = d / t and time is t = d / v. Knowing any two of the three gives the third.
If the speed varies along the way, v in the formula is the average speed: total distance divided by total time.
Watch the units
The formula only works when the units agree. Kilometres and hours give km/h. Metres and seconds give m/s. The two are linked by 1 m/s = 3.6 km/h. The calculator converts for you, so just pick the unit next to each field.
Example
A car covering 150 km in 2 hours has an average speed of 150 / 2 = 75 km/h. At 90 km/h the same car needs 450 / 90 = 5 hours for 450 km.
Limits
The calculation is for motion in one direction without stops. Traffic, breaks and changes of speed are not included. If the object speeds up or slows down, the equations of accelerated motion are needed.
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