Race time predictor

It takes Known distance (km), Known time (minutes) and Target distance (km) and derives Predicted time and Pace (min/km) from them. The calculation is live as you type, so the result updates on every change.

3 values: Known distance (km), Known time (minutes) and Target distance (km). Nothing else is required — no account, no file upload.

With Known distance (km) = 5, Known time (minutes) = 25 and Target distance (km) = 10, the calculator returns Predicted time = 52:07 and Pace (min/km) = 5:13. Those figures come from running this exact tool, so you can reproduce them by entering the same values.

Preparing a race: the pace a target time needs, the splits to hold it, and the training zones that sit under it — on foot, and equally on a bike or in a pool, where the same session is measured in watts or in a hundred-metre split instead.

Scaling a time linearly to a longer distance. A marathon is not two half-marathons; race predictors use an exponent around 1.06 precisely because fatigue is not proportional.

For general guidance only — not medical advice.

This one returns Predicted time; the Target race pace calculator returns Speed (km/h). That is the whole difference — open the one whose figure you need.

Pace to finish time calculator is the closest one after this: Turn your running pace and a race distance into an expected finish time.

Walking time calculator and Hiking Time Calculator (Naismith) — they come up in the same task often enough to be worth a second tab.

Pace arithmetic is exact. Race predictions follow Riegel's formula, which assumes training matched to the longer distance — without it the prediction is optimistic.