Race Time Equivalent Calculator
Predict a finish time at a new distance from a recent race (Riegel formula).
Your result
The Riegel formula is a rough predictor. It works best when the two distances are close and the athlete is trained for the target distance.
Medical disclaimer: This tool is for education and is not medical advice. Read more.
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Frequently asked questions
What does the Race Time Equivalent Calculator do?
Predict a finish time at a new distance from a recent race (Riegel formula). Enter your values and the result and chart update instantly.
How accurate is it?
It uses published, widely used formulas. Results are estimates for education and planning, not a diagnosis. Talk to a qualified clinician about decisions affecting your health.
Is my information stored or shared?
No. All calculations run in your browser and nothing you type is sent to a server or saved.
What can I search to find this tool?
People find it by searching for: predict my marathon time; race time equivalent; riegel race predictor.