Speed, Distance and Time Calculator
Choose your units, fill in two of speed, distance and time, and leave the third empty. The calculator works out the missing one and shows the speed in mph, km/h and m/s.
Your numbers
How we calculate it
The three are linked by speed = distance ÷ time, so distance = speed × time and time = distance ÷ speed. Everything is turned into meters and seconds first, using exact conversions (1 mile = 1,609.344 meters, 1 km/h = 1 ÷ 3.6 m/s), and the answer is turned back into your units.
At 60 mph for 2 hours the distance is 120 miles. A trip of 150 km in 2 hours 30 minutes is 60 km/h. 100 meters at 5 meters per second takes 20 seconds.
Assumptions and limits
- Leave exactly one of the three empty. For time, leave the hours, minutes and seconds boxes all empty.
- The calculation assumes a constant speed. It gives an average speed for a trip with stops or changes in speed.
- The speed in mph, km/h and m/s is shown for every result so you can compare units.
Frequently asked questions
How do I calculate speed from distance and time?
Divide the distance by the time. 150 kilometers in 2.5 hours is 150 ÷ 2.5 = 60 kilometers per hour.
How do I find how long a trip takes?
Divide the distance by your speed. A 90 mile trip at 60 mph takes 1.5 hours, which is 1 hour 30 minutes.
How do I convert km/h to m/s?
Divide by 3.6. 100 km/h is 27.78 meters per second. To go the other way, multiply by 3.6.
Related calculators
- Running Pace CalculatorEnter a distance and your finishing time to get your pace per mile and per kilometer, your speed and what the same pace would mean at common race distances.
- Gas Mileage CalculatorChoose the units you measured in, then enter the distance you drove and the fuel you used.
- Time CalculatorEnter two times as days, hours, minutes and seconds, and choose to add them or subtract the second from the first.
- Trip Fuel Cost CalculatorChoose your units, then enter the distance, your fuel economy and the fuel price.
Worked example (a fixed example using the starting numbers, it does not change as you type)
Inputs: Units = Miles and miles per hour; Speed (leave empty to solve) = 60; Time: hours (leave all three time boxes empty to solve) = 2.
- Speed 60.00 mph
- Distance 120.00 miles
- Time 2 hr
- Time in hours 2.0000
- Speed in mph 60.00
- Speed in km/h 96.56
- Speed in m/s 26.82
Embed this calculator
Add this calculator to your own page. Paste the code where you want it. The small link keeps credit to the source.