How this calculator works
Travel time is distance divided by speed, provided the two use compatible units. The page converts miles to metres and miles per hour to metres per second before dividing, so a mixture of miles, kilometres, miles per hour and kilometres per hour is handled correctly. The distance and speed modes rearrange the same relationship to find the missing value. The result is the time spent moving at the entered average speed; it does not add fuel stops, rest breaks or traffic delays, and it does not produce a departure or arrival clock time.
Formula
time = distance / speed. Distance = speed x time. Speed = distance / time. A mile is exactly 1,609.344 metres and 60 mph is 26.8224 metres per second.
Worked example
150 miles at 60 mph takes 150 / 60 = 2.5 hours, which is 2 hours 30 minutes. At 80 km/h, 240 km takes 3 hours, and the same 3 hours at 80 km/h covers 240 km.
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Frequently asked questions
Does the time include breaks?
No. The result is moving time at the entered average speed. Add breaks separately, or use the drive time calculator, which has a break field and a total time output.
What average speed should I enter?
Use the speed you can realistically sustain, including slowdowns, rather than the posted limit. A highway trip with town sections and traffic often averages less than the limit.
Can I mix miles and kilometres per hour?
Yes. Each field is converted to its base unit before the calculation, so miles with km/h or kilometres with mph both work. The displayed distance and speed follow the unit selectors, not the input units.
Why is my navigation app different?
A navigation app uses live traffic, road speed profiles and turn-by-turn routing. This page uses one constant average speed and a straight distance, so it is a planning estimate, not a route prediction.