When to use this calculator
A simple average of the two speeds is incorrect for equal distances because more time is spent on the slower leg.
Explore the journey time & travel budget calculators for other questions in this topic. For a related calculation, use the Carpool Cost Calculator: Split journey fuel spending equally across travellers.
PUTTING IT INTO PRACTICE
Average Speed for Equal Distances: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| First leg speed (km/h) | 30 |
| Second leg speed (km/h) | 60 |
| Result | 40 km/h |
- Check the input labels and enter the example values above.
- Apply the relationship: Average speed = 2/(1/first speed + 1/second speed).
- The result is 40 km/h, rounded for display.
How to interpret your result
Leg distances must be equal; waiting time is excluded.
Average speeds should include the delays relevant to your question. Equal-distance and equal-time speed averages use different methods. Compare trip budgets with consistent expense categories and journey boundaries.
Frequently asked questions
Why is average speed for equal-distance legs not a simple average?
More time is spent on the slower leg. Divide total distance by total travel time, which produces the harmonic mean for two equal-distance legs.
When is the average speed for equal distances calculator useful?
A simple average of the two speeds is incorrect for equal distances because more time is spent on the slower leg.
How do I use the average speed for equal distances calculator?
Enter first leg speed (km/h), second leg speed (km/h). The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Average speed = 2/(1/first speed + 1/second speed).
What should I check before using the result?
Leg distances must be equal; waiting time is excluded.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
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