Health & Fitness
Running Splits (Riegel) Calculator
Predict finish time for a new race distance from a recent race result using the Riegel formula.
Preparing your result…
What this calculator does
Calculates Running Splits (Riegel) Calculator using the formula verified against the cited source.
What your result means
An estimate from the inputs you enter, within the scope stated below — not advice.
Formula
T2 = T1 × (D2 ÷ D1)^1.06
The step-by-step working for your own numbers appears with the result above and in the PDF report.
Frequently asked questions
Symbols and assumptions
- Inputs
- The values entered in the fields above
- • Riegel power-law race-time estimate: target time=known time×(target distance/known distance)^b, with b≈1.06 as an illustrative endurance exponent. The result is an equivalent performance estimate.
Sources and review
Reviewed 2026-10-18 · Next review 2027-04-18
- • All distances share one unit and times one unit; positive values required. This does not generate kilometer splits by itself. Exponent, endurance training, terrain and weather affect accuracy, especially large distance extrapolations.
Important limitation
This is an educational estimate based only on the values and formula shown. Verify current rates, rules, units, and professional standards before relying on the result. It is not personalized financial or investment advice.
Quick reference
| Scenario | Known race distance (km) | Known race time (min) | Target race distance (km) | Predicted finish time |
|---|---|---|---|---|
| Worked example | 10 | 50 | 21.1 | 1:50:20 |
| Half the amounts | 5 | 25 | 10.6 | 55:27 |
| Double the amounts | 20 | 100 | 42.2 | 3:40:40 |
Need the full picture? Get the detailed PDF report with charts, tables, formulas and working steps.
Reviewed 2026-10-18 · Next review 2027-04-18
Report a mistake or request an improvement
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