What does equivalent performance mean?

An equivalent performance is the predicted time at a different distance that represents the same level of fitness. A 20:00 5K and a 41:30 10K are roughly equivalent performances.

Why are my actual times different from predictions?

Distance-specific training affects performance. A runner who trains mostly for 5K may outperform their Riegel prediction at 5K but underperform at the marathon. The formula assumes well-rounded training.

Which distance gives the most accurate predictions?

Predictions are most accurate when the known and target distances are close together. A 10K time predicts half marathon better than a 1-mile time would.

RunCalcs

Equivalent Performance Calculator — Compare Across Distances

Find equivalent performances across different race distances based on your fitness level.

Known Distance

Distance measurement

Hours

Time in hours

Minutes

Time in minutes

Seconds

Time in seconds

How We Calculate This

Equivalent Performance

Uses the Riegel formula: T2 = T1 × (D2/D1)^1.06

This produces equivalent times across all standard race distances from 800m to marathon, representing the same fitness level.

Frequently Asked Questions

Related Calculators

Marathon Time Predictor

Predict your marathon time from a shorter race result.

Half Marathon Predictor

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

10K Predictor

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

5K Predictor

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

Parkrun Predictor

Predict your parkrun time from other race distances.

Last updated: February 2026

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