Free running calculator

Race Pace & Equivalent Time Calculator

Enter a recent race result and use it as a guide for equivalent race times and paces over other common distances.

Race pace guide5K to marathonPace per km & mileNo sign-up

Tips for Better Results

Race predictions are most useful when you treat them as a guide alongside your training, rather than as an exact promise of what you will run.

1Use a similar-distance result

Predictions are generally most accurate when your recent race is reasonably close in distance to your target. For example, a 10K result usually gives a better half-marathon guide than a 1-mile result.

2Be cautious with marathon estimates

Marathon predictions based on short races such as a 5K can be optimistic unless you have the endurance, long runs, fuelling practice and marathon-specific training to support that pace.

3Use the result as a target, not a guarantee

Race-day conditions matter. Hills, trail terrain, heat, wind, fatigue, pacing and fuelling can all change the pace you can realistically hold.

How to use the guide

1Use a genuine recent effort

A recent race or hard time trial is much more useful than a training run where you had plenty left.

2Compare nearby distances first

A 5K result usually gives a stronger guide to 10K than it does to a marathon because the endurance demands are closer.

3Apply coaching judgement

Use the predicted pace alongside your training history, long-run endurance, terrain and current race-specific work.

Your recent result

For the best guide, use a recent race or hard time trial on reasonably similar terrain and conditions.

Hours
Minutes
Seconds
Use this as a guide, not a promise. Equivalent-time calculators assume your endurance is developed appropriately for the target distance. Marathon estimates in particular can be optimistic if long-run endurance, fuelling or race preparation are not yet in place.
Enter a recent race result

Your target race time and pace guide will appear here.

Target guide
Equivalent race time—Target distance
Average pace—per kilometre
Race pace guide

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Pace / mile—
400 m split—
1 km split—

Equivalent race guide

These are estimated equivalents from your entered result. Your best real-world pace may be a little faster or slower depending on training, terrain, weather, race profile, fuelling and how well suited you are to each distance.

DistanceEquivalent timePace / kmPace / mile400 m split
Calculate a recent result to fill the race guide.

How the estimate is calculated

The calculator uses the Riegel race-prediction relationship, a commonly used way of estimating equivalent performances between running distances.

Predicted time = known time × (target distance ÷ known distance)1.06

The 1.06 exponent is a general endurance guide. Individual runners vary, so equivalent times should be treated as planning guidance rather than an exact prediction.

Important: pace calculators do not account for injury, illness, heat, hills, trail terrain, wind, elevation or individual fatigue. Adjust pace targets to the conditions and how you are running on the day.