Speed Distance Time Calculator
Solve for speed, distance or time.
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Pick what you want to find in the Solve for menu (speed, time or distance), fill in the two other values, and this calculator does the rest. Distance is in kilometres, time in hours and speed in km/h. It suits trip planning, school physics problems and working out a running or cycling pace.
The three formulas and which boxes each one uses
| Solve for | Fill in | Formula |
|---|---|---|
| speed | Distance, Time | distance ÷ time |
| time | Distance, Speed | distance ÷ speed |
| distance | Speed, Time | speed × time |
The box you are not using is ignored, so you can leave an old value in it. Speed and distance answers are rounded to two decimals; a time answer is shown in hours and minutes, with minutes rounded to the nearest whole minute.
Entering minutes as decimal hours
The Time field takes hours as a decimal number, so divide minutes by 60 before typing them in:
- 15 minutes = 0.25 hours
- 20 minutes ≈ 0.333 hours
- 45 minutes = 0.75 hours
- 2 hours 30 minutes = 2.5 hours
Worked examples
- How long will the drive take? 275 km at an average of 60 km/h: 275 ÷ 60 = 4.583 hours, shown as 4h 35m.
- What was my average speed? 180 km covered in 2 hours 30 minutes: 180 ÷ 2.5 = 72 km/h.
- How far will I get? 80 km/h for 1 hour 45 minutes: 80 × 1.75 = 140 km.
- Marathon pace: 42.195 km at a steady 10 km/h takes 4h 13m.
Average speed is not the number on the speedometer
For trip planning, the speed to use is your average over the whole journey, including tea breaks, toll plazas, fuel stops and slow stretches through towns. A car that cruises at 90 km/h on the highway may average far less door to door, so time estimates based on cruising speed come out too optimistic.
Also, you cannot average two speeds by adding them and halving. Drive 60 km at 60 km/h and the next 60 km at 30 km/h: the first leg takes 1 hour and the second 2 hours, so 120 km in 3 hours is an average of 40 km/h, not 45. Always divide total distance by total time.
Other units
The labels say km and km/h, but the maths works with any matching units. Enter miles and hours and the speed result is really in mph. To convert, multiply m/s by 3.6 to get km/h, and multiply miles by 1.609344 to get kilometres; the speed converter handles km/h, mph, m/s and knots. Once you know the distance, the fuel cost calculator tells you what the trip will cost to drive.