Running pace calculator with race time predictions
Turn a distance and finish time into minutes per kilometre, minutes per mile and average speed. Use the separate race-time estimates to explore other distances.
Runs in your browser — your input is not uploaded to ToolsNow.
Leave hours empty for anything under an hour.
Race predictions use Riegel’s formula (T₂ = T₁ × (D₂/D₁)^1.06). They assume you have trained for the target distance. A 5K time alone cannot show marathon readiness; terrain, weather and endurance also affect your finish time.
How to use
- Set the distance. Choose kilometres or miles and enter the distance, or select a race preset.
- Enter the finish time. Use the hours, minutes and seconds boxes. For a 25-minute 5K, enter 5 km, 25 minutes and 0 seconds; hours can stay blank.
- Read pace before predictions. That example gives 5:00/km, about 8:03/mile and 12 km/h. The other race times are model estimates rather than the same pace carried over.
Questions
Should I enter moving time or elapsed time?
Use the time that matches your question. Elapsed time includes stops and is useful for a finish-time comparison; moving time describes the portions recorded as movement. Use the same convention when comparing runs.
How are the other race times estimated?
The table uses Riegel’s formula: new time = entered time × (new distance ÷ entered distance)^1.06. A 25:00 time for 5 km gives about 52:07 for 10 km. The formula allows pace to slow as distance increases.
Can I use a 5K result as a marathon target?
The prediction alone is not enough. It assumes preparation appropriate to the longer distance and does not account for terrain, weather, stops or individual endurance. A calculated time is not a recommendation to attempt that distance or pace.
How do pace and speed relate?
For minutes per kilometre, divide 60 by the pace to get km/h. At 5:00/km, 60 ÷ 5 = 12 km/h. Lower pace numbers mean faster movement.
How it works and sources
How this is calculated
Pace is time divided by distance; speed is distance divided by time. The tool converts these to minutes per kilometre or mile and kilometres or miles per hour. Race predictions use T₂ = T₁ × (D₂ ÷ D₁)^1.06: a known time and distance are scaled to a new distance. The Riegel paper is background for this model, not a guarantee for an individual runner.
What the calculation assumes
- Use a recent effort that represents your ability at the entered distance. An easy training run is not a race result.
- Predictions assume suitable endurance training for the target distance. Pace and speed depend on the accuracy of your time and distance measurements; displayed results are rounded.
Where the result has limits
- A short-distance result can give an unrealistic marathon estimate if you have not trained for the longer distance.
- Terrain, weather, altitude, pacing and individual endurance are not included.
- Treat predicted times as rough comparisons, not promises or an assessment of whether you are ready to run a distance.
Sources
Sources last checked 30 July 2026.
These estimates are general information, not medical advice.
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