What this result means
Two published ways to move a race across distances sit on this site. The race time predictor uses Riegel with exponent 1.06. This page uses Daniels VDOT: estimate VDOT from the race you ran, then invert the same formulas to find times at the mile, 5K, 10K, half, and marathon that match that VDOT.
The numbers will not match Riegel exactly. That is useful. If both models agree, the planning range is tighter. If they disagree, the distance jump is doing a lot of work and you should treat both as estimates.
A 20:00 5K is roughly VDOT 50. Equivalent 10K, half, and marathon times are the performances that yield the same VDOT, not a simple doubling. A 46:20 10K produces a different VDOT and a different table.
Skip the input distance in the table — if you entered a 10K, you already know that time. Compare the half and marathon rows with the Riegel predictor on the same inputs.
Calculation method
VDOT is estimated from race distance and time with Daniels’ oxygen-cost and percent-VO2 formulas. Equivalent time at another distance is found by searching for the clock that returns the same VDOT. Cite: Daniels, J., Daniels’ Running Formula, Human Kinetics.
Deterministic: the same race always yields the same table. It is still a model of endurance fitness, not a lab VO2 test.
VDOT assumes the race represents current fitness. A downhill 5K inflates the marathon row. Heat, hills, and a training block aimed at one distance are not in the inversion. For a required time at a known distance to hit a goal, use inverse Riegel on the required-performance tool.
Frequently asked questions
Is this the same as the race time predictor?
No. That page is Riegel. This page is Daniels VDOT equivalents. Compare both; they are different models.
What is VDOT here?
An index of endurance fitness from a race. Training paces use the same index for zones. This tool uses it for equivalent race times.
Why don’t the times match Riegel?
Different formulas. Riegel is a power law on distance. VDOT inverts Daniels’ race-to-oxygen model. Neither is a measurement.
What does a 20:00 5K equivalent to?
About VDOT 50, then a 10K, half, and marathon that match that VDOT. Open the tool with 5K and 20:00 for the table.