Free calculator

Running pace calculator and race predictor

This calculator gives you your pace per kilometre and per mile, your average speed and predicted times for other distances from one finish time. Pick 5 km, 10 km, half marathon or marathon and enter your time.

How it's calculated

Pace is your finish time divided by the distance, shown in minutes per km and per mile (1 mile = 1.609 km). Speed is the same number turned around into kilometres per hour. A 30:00 5 km, for example, is 6:00 per km, 9:39 per mile and 10.0 km/h.

Predictions use the Riegel formula, published by Peter Riegel: T2 = T1 × (D2 ÷ D1)^1.06. The exponent of 1.06 reflects that pace drops slightly as distance increases. From a 30:00 5 km it predicts about 1:02:30 for 10 km and about 2:18 for a half marathon.

Riegel assumes you've trained for the longer distance. A beginner who has only trained for 5 km will usually run a half marathon slower than predicted, so treat long-distance predictions as a ceiling, not a target.

Using a pace to set a 5 km goal? The couch to 5K builder adds per-km goal splits for sub-35, sub-30 and sub-25 minutes to your journal.

Frequently asked questions

What pace is a 30-minute 5K?

A 30-minute 5K is 6:00 per km, or about 9:39 per mile, which is an average speed of 10 km/h. A 25-minute 5K is 5:00 per km and a 35-minute 5K is 7:00 per km.

How accurate is the Riegel race predictor?

It's reasonably reliable between similar distances, such as 5 km to 10 km, when you've trained for both. The further apart the distances and the less specific your training, the more optimistic it becomes.

What is a good running pace for a beginner?

A good beginner pace is one where you can talk in full sentences. For many new runners that's somewhere around 7:00 to 9:00 per km, but effort matters more than the number.

Does the calculator work for treadmill runs?

Yes. Enter the treadmill distance and time. Set a 1% incline when you run, as it brings the effort closer to running outdoors.

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General fitness information, not medical advice. Check with a doctor if you have a medical condition, are pregnant or have an injury.