Feb 04

Riegel’s Formula

Category: Performance

Riegel’s formula is a mathematical equation used to predict race times for runners. It was first published by Pete Riegel, an American research engineer in 1977.

The formula takes into account a runner’s recent race time and distance to then estimate the time to complete an upcoming race:

T2 = T1 x (D2 / D1) ^ 1.06


  • D1 = Previous race distance
  • D2 = Upcoming race distance
  • T1 = Previous race time
  • T2 = Prediction of race time for upcoming race

Overall, the evidence suggests that Riegel’s formula is a useful tool for predicting race times in runners, but it should not be relied upon as the sole means of determining race performance. Other factors such as recent training history and specificity should also be taken into account when predicting race times.

Despite its limitations, Riegel’s formula continues to be widely used by runners, coaches, and exercise physiologists to help predict race times and track performance improvements.

About The Author

Dr. Sean Radford, the Founder & CEO of TrainAsONE, is a medical doctor, IT expert, coach and podium finisher in international endurance events. He has dedicated more than 20 years to the research of health, fitness and social well-being of the general population. He has been developing Artificially Intelligent (AI) and Machine Learning (ML) tools to help tackle some of the world’s leading health issues. Dr Radford is a Tech Ambassador for the UK, considered a leading expert in his field, and is a regular speaker at key events, as well as an author of numerous research publications.