Predict Your Half marathon Time From a 10 mile

How a 10 mile predicts your Half marathon

Ten miles is one of the best races to predict a half marathon from, because it sits only just over three miles short of the full distance. Classics like the Cherry Blossom Ten Mile and Broad Street fill up every year partly because they are such an honest dress rehearsal for the half. The endurance you show over ten miles carries almost directly to the 13.1.

Because the gap is so small, the prediction is tight. Your half pace will be only slightly slower than your 10 mile pace, and as long as you have a couple of longer runs in your legs, the predicted half is a realistic goal rather than a guess. This is one of the most reliable conversions on the site.

Only three miles of unknown

When you race ten miles, you have already covered more than three quarters of a half marathon at racing effort. That leaves just over a 5K of new ground, so Riegel only has to add a small slowdown of around three to four percent. The prediction holds up well precisely because there is so little left to extrapolate.

The main consideration is whether your endurance reaches the full distance. If your long runs comfortably pass ten miles, trust the prediction and pace the half just a touch slower than your 10 mile effort. If ten miles is currently your ceiling, the number is still your speed target, you just want a few longer runs first to be sure the final stretch holds together.

Want every distance at once? The race pace predictor shows your time for the whole range and prints a pace band, and the VDOT calculator turns this race into your training paces.