Average speed calculator
The average speed of a journey in km/h, m/s and miles per hour.
Calculator inputs
Results
Enter your values and press “Calculate” to see the result.
In short
- What it calculates
- The average speed of a journey in km/h, m/s and miles per hour.
- Formula used
Speed = distance ÷ time- Example
- 250 km in 2 hours 45 minutes:
Average speed calculator
A journey's average speed is always lower than the cruising speed, because it includes stops, traffic lights and queues.
Comparing it with the speed you think you were doing is usually revealing.
How it works
Distance is divided by the time expressed in hours. Time is entered as HH:MM and converted internally to minutes, which avoids base-60 mistakes.
Formula
Speed = distance ÷ time
m/s = km/h ÷ 3.6
mph = km/h ÷ 1.609344
Worked example
250 km in 2 hours 45 minutes:
2:45 = 2.75 hours
Speed: 250 ÷ 2.75 = 90.91 km/h
That is 25.25 m/s or 56.49 mph.
Explanation
The average of speeds is not the average speed
If you drive out at 100 km/h and back at 50, your average speed is not 75 but 66.7. The reason is that you spend twice as long on the slow leg, so it weighs more in the total. Average speed is always total distance divided by total time, never the mean of the speeds.
The harmonic mean
When the legs cover the same distance, the average speed is the harmonic mean of the speeds. It is an unintuitive case but a very common one in travel problems, and it explains why speeding up on the return trip helps less than expected.
Why driving faster saves less time than it seems
Covering a hundred kilometres at 120 instead of 100 saves ten minutes. At 140 instead of 120, only seven. Each increment in speed yields less saved time, while consumption and risk rise. It is an inverse relationship, not a linear one.
Pace instead of speed
Running and swimming use pace: minutes per kilometre rather than kilometres per hour. It is more useful because it lets you plan split times directly at each point of the route.
Frequently asked questions
Why is the average lower than I expected?
Because total time includes stops. Driving at 120 km/h for two hours and stopping for half an hour averages only 96 km/h.
Can I use it for running or cycling?
Yes. For running, pace in minutes per kilometre is usually more useful, and it is shown too.
Why is my average speed lower than the average of my speeds?
Because you spend more time on the slow sections, which therefore weigh more. Average speed is always total distance over total time.
How much time do I save going faster?
Progressively less. Going from 100 to 120 km/h over a hundred kilometres saves ten minutes; from 120 to 140, only seven.
Need to calculate something else?
These tools are often used alongside this calculator.
Fuel use
Real-world consumption in litres per 100 km from a full tank fill.
Trip cost
Fuel, tolls and the split between everyone in the car.
Running pace
Your pace per kilometre or mile, the time or distance you are missing, splits and predicted 5K, 10K, half…