What 5K time predicts a sub-40 10K?

A 5K time of approximately 19:00-19:30 predicts a sub-40-minute 10K.

Is a 10K double my 5K time?

No, a 10K is typically 2.08-2.12 times your 5K time due to the fatigue factor. So a 25:00 5K predicts roughly 52:00-53:00 for 10K, not 50:00.

The average UK 10K finish time is around 55-60 minutes. Sub-40 is excellent, sub-45 is very good, sub-50 is good for a club runner.

Predict your 10K race time from a 5K or parkrun result.

Race Distance

Minutes

Seconds

T2 = T1 × (10 / D1)^1.06

Uses the Riegel formula with the target distance of 10 km.

Predict your marathon time from a shorter race result.

Predict your half marathon time from 5K or 10K results.

Predict your 5K time from shorter or longer race results.

Predict your parkrun time from other race distances.

Predict ultra marathon times for 50K, 50mi, 100K and 100mi.

Last updated: February 2026

All calculations are estimates. Always consult a coach or medical professional for personalised training advice.