How much faster is 10K pace than half marathon pace?

Usually around 20 to 30 seconds per mile. The 10K is less than half the distance, so you can hold a meaningfully quicker pace, and Riegel reflects that with a multiplier near 0.45.

Is a half marathon a good predictor of 10K?

Yes. Both races run near your aerobic threshold, so a recent half predicts your 10K well, often within half a minute for runners who race both.

Why might my 10K be slower than predicted?

Most often a lack of fast training. The endurance is there from your half, but without intervals or tempo work your legs may not yet turn over quickly enough to hit the predicted pace.

Predict Your 10K Time From a Half marathon

Ran a Half marathon lately? Enter your time to see what it predicts for the 10K, plus the pace you would need to hold.

Your Half marathon time

min

sec

Pace in

Predicted 10K time

45:19

That is 7:18 per mi.

Worked example

A Half marathon of 1:40:00 predicts a 10K of about 45:19, a pace of 7:18 per mi. Change the time above to run the same math on your own result.

How a Half marathon predicts your 10K

Working back from a half marathon to a 10K is a dependable estimate. Both races sit close to your aerobic threshold, so your fitness carries over cleanly, and the shorter distance simply lets you run a faster pace the whole way. Your predicted 10K should be a good bit quicker per mile than your half pace.

If you race 10Ks regularly, you may even nudge under the prediction, because the 10K is short enough to push hard and you likely have a little more top-end speed than a half effort shows. Runners who rarely race short will land right on the predicted time.

How much faster your 10K should be

Riegel multiplies your half time by about 0.45 to land on the 10K, not a simple halving-and-a-bit. That captures the real jump in pace you get from cutting the distance by more than half. A 1:40 half predicts roughly a 45:20 10K, which is around 30 seconds per mile faster than half-marathon pace.

If your 10K comes out slower than predicted, the usual culprit is a lack of faster running in training. The endurance from your half is clearly there, you just need a few weeks of intervals or tempo work to teach your legs to turn over quicker. Add that and the predicted 10K becomes very reachable.

One practical note, run the 10K itself a touch more aggressively than you would a half. Because it is so much shorter, you can afford to start near your goal pace rather than easing in over the first few miles. A controlled but committed opening kilometer, then holding on, is usually how a half-based 10K target actually gets hit.

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.

Related predictions

Half marathon to 10K questions

How much faster is 10K pace than half marathon pace?: Usually around 20 to 30 seconds per mile. The 10K is less than half the distance, so you can hold a meaningfully quicker pace, and Riegel reflects that with a multiplier near 0.45.
Is a half marathon a good predictor of 10K?: Yes. Both races run near your aerobic threshold, so a recent half predicts your 10K well, often within half a minute for runners who race both.
Why might my 10K be slower than predicted?: Most often a lack of fast training. The endurance is there from your half, but without intervals or tempo work your legs may not yet turn over quickly enough to hit the predicted pace.