# Running Pace Calculator and Race Time Predictor

Work out your pace per kilometre and per mile from a distance and time, and predict your 5K, 10K, half marathon and marathon times.

- URL: https://toolstackhub.co.uk/tools/running-pace-and-race-time-predictor/
- Category: Calculators
- Price: free, no sign-up
- Privacy: runs in the browser; input is not uploaded
- Last updated: 2026-10-08

## About
The Running Pace Calculator turns a distance and time into your pace per kilometre and per mile and your speed in km/h and mph, then predicts your finish times at other distances using the Riegel formula, which says time grows with distance to the power of 1.06. It is a good guide when your training is consistent, but longer races need more endurance than the formula assumes, so treat the marathon figure as a best case.

## How to use
1. Choose the distance you ran, or Custom distance and its unit.
2. Enter your finish time in hours, minutes and seconds.
3. Read your pace per kilometre and mile and your speed.
4. Use the prediction table to see what the same effort could mean at 5K, 10K, half marathon and marathon distances.

## FAQ
**How do I calculate running pace?** Divide your total time by the distance. A 25-minute 5K is 25 ÷ 5 = 5 minutes per kilometre.

**How do I convert min per km to min per mile?** Multiply by 1.609344. 5:00 per km is 8:03 per mile.

**How accurate is the race predictor?** It is a reasonable guide from 5K to the half marathon if your training suits the distance, and less reliable for the marathon.

**Is the Running Pace Calculator and Race Time Predictor free?** Yes, with no sign-up or limits.