Use this running race time predictor to estimate a possible finish time over another distance from a recent measured result. It can help you set a training target for a 5K, 10K, half marathon or marathon, but it is an estimate rather than a promise.
Race time predictor
Estimate a possible finish time using your recent race, current weekly training, consistency and target-course profile. The added context adjusts the estimate modestly; it is still a guide, not a promise.
Why this calculator is useful
Explore a rough finish-time equivalent from a recent measured race. Predictions work best with a recent result and comparable conditions.
How to use it
- Enter a recent, representative result or your planned race details, using the units shown beside each field.
- Select Calculate and review the result, including the assumptions and limitations shown.
- Use the result as a planning aid, compare it with how you feel, and recalculate when your inputs change.
Results are estimates, not guarantees. Fitness, recovery, weather, terrain, elevation and course conditions can all change the outcome.
Related running resources
All running calculators · Running guides · Training plans · UK race calendar · Triathlon and Ironman guide
Frequently asked questions
How accurate is a race time prediction?
It is a mathematical estimate based on a recent result. Endurance, training consistency, course profile, weather and pacing can make your actual time faster or slower.
Which recent result should I enter?
Use a recent, representative effort over a measured distance, ideally completed when healthy and reasonably rested.
Does the prediction account for hills or trail terrain?
No. It assumes broadly comparable conditions and does not model hills, surface, heat or technical trails.
How race time prediction works
A distance-based model projects a result from one distance to another. It cannot fully account for your endurance, recent training, course elevation, weather, fuelling or race-day conditions. Longer-distance predictions are especially sensitive to how much endurance training you have completed.
Use your prediction sensibly
Start with a recent result that reflects your current fitness. Compare the estimate with your current weekly running and longest comfortable session. Use the result as a reference for planning, not a reason to force a pace that feels unsustainable.
Related tools: running pace calculator · race split planner · training pace calculator · training plan builder.
Are predicted race times accurate?
They are rough estimates. Individual endurance, course profile, weather, health, fuelling and training consistency can produce a different result.
Which recent race should I enter?
Choose a measured event or effort completed recently while healthy and representative of your current fitness.