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Average Speed Calculator
Average speed sounds simple, but it hides a trap: it is not the middle of your speeds, it is your total distance divided by your total time. This average speed calculator does it properly in three ways — for one trip from distance and time, for a journey split into legs that each moved at a different pace, and for the classic return trip, where you go out at one speed and come back at another.
How to use this tool
- Pick the mode: one trip, several legs, or a return trip.
- For one trip, enter the total distance and the total time in hours, minutes, and seconds.
- For legs, give each part of the journey its own distance and time — a fast motorway leg, then a slow town leg, for example.
- For a return trip, enter the speed going and the speed coming back over the same road.
- Read the big number for the true average speed, and the line below for the totals it came from.
Average speed examples
| Distance | Time | Average speed |
|---|---|---|
| 100 km | 2 hours | 50 km/h |
| 160 km | 3 hours | 53.33 km/h |
| 450 km | 7 hours 30 minutes | 60 km/h |
| 26.2 miles (a marathon) | 4 hours | 6.55 mph |
| 10 km | 50 minutes | 12 km/h |
| 1,000 km | 12 hours 30 minutes | 80 km/h |
Every row is the same calculation: distance divided by time. A marathon runner holding 6.55 mph for four hours covers the same ground as a cyclist doing 12 km/h for a 10 km ride covers in fifty minutes — steady effort, measured honestly.
How it works
Average speed has one exact definition: total distance divided by total time. Nothing else. It does not matter how your speed rose and fell along the way — if you covered 160 kilometres in 3 hours, your average speed was 53.33 km/h, even if you touched 90 on the motorway and crawled at 20 through a town.
The legs mode simply applies the definition honestly: add all the distances, add all the times, then divide. This is why averaging the leg speeds gives the wrong answer. Two legs at 50 km/h and 60 km/h do not average to 55 unless they lasted the same time. If the 50 km/h leg took 2 hours and the 60 km/h leg took 1 hour, you spent twice as long at the slower speed, so the true average, 53.33 km/h, sits closer to 50.
The return trip is the famous special case. Going out at speed A and coming back at speed B over the same distance, the average is 2AB ÷ (A + B) — the harmonic mean. Out at 40 km/h and back at 60 km/h averages 48 km/h, not 50, because you spend longer on the slow outward leg. Cyclists fighting a headwind learn this the hard way: the wind always wins more on the way out than it gives back on the way home.
Worked example
A delivery rider covers the first 100 km of a route in 2 hours on slow roads, then the last 60 km in 1 hour on a motorway. What is the average speed for the whole route?
Step 1: Add the distances — 100 + 60 = 160 km.
Step 2: Add the times — 2 + 1 = 3 hours.
Step 3: Divide — 160 ÷ 3 = 53.33 km/h.
Step 4: Check the trap — the simple middle of the two leg speeds, 50 and 60, would be 55 km/h, which is wrong because the rider spent twice as long at 50.
So the true average speed is 53.33 km/h — the same result the legs mode of this calculator gives for those two legs.
FAQ
How do I calculate average speed?
Divide the total distance by the total time. For example, 160 km in 3 hours gives 160 ÷ 3 = 53.33 km/h. Always add up all the distance and all the time first — never average the speeds directly.
Why is my average speed not the middle of my two speeds?
Because you spend different amounts of time at each speed. If you travel for 2 hours at 50 km/h and 1 hour at 60 km/h, most of your journey was at the slower speed, so the average of 53.33 km/h sits closer to 50 than to 60.
What is the average speed of a return trip at 40 km/h and 60 km/h?
It is 48 km/h, not 50. For the same distance each way, the average is 2 × 40 × 60 ÷ (40 + 60) = 48 km/h. The slow leg takes longer, so it counts for more of the journey.
How do I enter a time like 1 hour 45 minutes?
Put 1 in the hours box and 45 in the minutes box. The calculator adds them together — 1.75 hours — before dividing. For a single trip you can also add seconds for race times and timed tests.
Can I calculate average speed in mph?
Yes. Choose Miles as the distance unit and the answer is given in mph, with the km/h figure shown alongside. The formula is identical — only the units change.
Does stopping for a break lower my average speed?
If you include the break in the total time, yes. Average speed for a whole journey usually counts all the time from start to finish. If you want your moving average only, leave the break time out of the time you enter.
Note: average speed is always total distance divided by total time. If you include stops in the time, the average will be lower — both answers are correct, they just measure different things.