🏃 Running Pace Calculator

Enter any two of distance, time, and pace and the calculator finds the third. You'll also get per-kilometre or per-mile splits and predicted finish times for 5K, 10K, half marathon, and marathon.

Last reviewed: June 2026Built & maintained by RahulMethodology & sourcesRace predictions use the Riegel model and assume similar conditions and appropriate training — treat them as estimates.

Fill in any two — leave the one you want to find blank.

How to Use the Pace Calculator

Pace, time, and distance are linked by one simple relationship: pace = time ÷ distance. Give the calculator any two of them and it solves for the third. Want to know what pace gets you a sub-25-minute 5K? Enter 5 km and 25:00 and read off the pace. Planning a long run at an easy pace? Enter the pace and the distance to see your finish time.

Reading Your Splits

The splits table shows the cumulative time you should hit at each kilometre or mile if you hold an even pace. Even (or slightly negative) splits are the hallmark of a well-paced race — going out too fast is the most common reason runners fade in the back half.

Race-Time Predictions

From one known effort, the calculator predicts your finish times at standard distances using Peter Riegel's formula: T₂ = T₁ × (D₂ / D₁)^1.06. The 1.06 exponent accounts for the fact that you slow down slightly as distance increases. Predictions are most accurate when the race you enter is close in distance to the one you're predicting, and when you're trained for the longer event.

Pace Tips

Frequently Asked Questions

Pace is your time divided by distance. Enter the distance you ran and the time it took, leave the pace field blank, and click Calculate — you'll get your pace per kilometre or mile, plus splits and race predictions.
Yes. Enter your 5K distance and time and the race-predictions table estimates your 10K, half, and marathon times using the Riegel formula. Note that predictions for much longer distances assume you've done the appropriate endurance training.
There's no single "good" pace — it depends on fitness, terrain, and goals. For most new runners, an easy, conversational pace where you can still talk is ideal for building endurance. Use the calculator to plan realistic targets and track progress over time.
Switch the Units selector between Kilometres and Miles and recalculate — the pace, splits, and predictions all update to the chosen unit. One mile is 1.609 km, so per-mile paces are a bit slower-looking than per-km paces for the same effort.
Use hours:minutes:seconds for time (e.g. 1:45:30) or minutes:seconds for shorter efforts and pace (e.g. 25:00 or 5:00). You can also enter plain seconds. The calculator formats the result the same way.