Average Trip Speed Calculator

Work out average trip speed instantly with clear inputs, formula shown and shareable results.

About Average Trip Speed Calculator

Average speed is total distance divided by total time, not the average of the speeds. Because slow sections consume disproportionate time, the true average always falls below the arithmetic mean — often by a surprising margin.

Formula

Average speed

average = total distance / total time; averaging the speeds themselves is wrong

Worked example

With the default values below, Average Trip Speed Calculator returns Overall average speed of 74.25. Change any input above and every figure here is recalculated in your browser.

Inputs used

First leg distance: 120 km
First leg speed: 110 km/h
Second leg distance: 60 km
Second leg speed: 45 km/h

Results

Overall average speed: 74.25 km/h
Total time: 2.42 h
Total distance: 180.00 km
Arithmetic mean of the two speeds: 77.50 km/h

Step by step

1Values used
2Average speed
3Overall average speed= 74.25 km/h
4Total time= 2.42 h
5Total distance= 180.00 km
6Arithmetic mean of the two speeds= 77.50 km/h

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why is averaging speeds wrong?

Because each speed applies for a different duration. The slow leg dominates the time, so it dominates the average.

What is the harmonic mean?

For equal distances at different speeds, the correct average is the harmonic mean: 2 / (1/v1 + 1/v2). This calculator handles unequal distances directly.