How it works
VDOT = VO₂(v) ÷ %VO₂max(t)
Daniels and Gilbert model a race two ways and divide one by the other. The **oxygen cost** of your race velocity v (in metres per minute) is VO₂(v) = −4.60 + 0.182258·v + 0.000104·v² — roughly how much oxygen the pace demands. The **fraction of VO₂max** you can sustain for a race lasting t minutes is %VO₂max(t) = 0.8 + 0.1894393·e^(−0.012778·t) + 0.2989558·e^(−0.1932605·t) — longer races run at a lower fraction. Dividing the cost by the sustainable fraction gives VDOT, an effort-equivalent VO₂max. Because any two races at the same VDOT must satisfy the same equation, the equivalent times are found by solving that relationship for each distance — the same method behind Daniels’ printed tables. We compute in SI units (metres, seconds) and convert only at the edge, so the mile and kilometre views never drift apart.
Sources
- Daniels & Gilbert — the VDOT model Jack Daniels & Jimmy Gilbert, “Oxygen Power: Performance Tables for Distance Runners” (1979). The VO₂-cost and %VO₂max regressions used here are from this work.
- Daniels’ Running Formula Jack Daniels, “Daniels’ Running Formula,” 4th ed. (Human Kinetics, 2021) — VDOT tables, training paces and the equivalent-performance method.
- VO₂max background VDOT is an effort-based stand-in for laboratory VO₂max: it ranks race performances, not a measured oxygen uptake.
FAQ
What is a VDOT score?
VDOT is Jack Daniels’ measure of running fitness — a "pseudo-VO₂max" calculated from a race result rather than a lab test. Two runners with the same VDOT should run similar times across distances, which is why it works so well for setting goals and training paces.
How is VDOT different from VO₂max?
A true VO₂max is the volume of oxygen your body uses at maximum effort, measured in a lab. VDOT is inferred from how fast you actually race, so it folds in running economy and endurance, not just oxygen uptake. The numbers are on a similar scale but VDOT describes performance, not physiology directly.
Which race should I enter?
Use a recent, hard race over 1.5 km to the marathon — the model is calibrated for that range. A fresh, well-paced effort gives the truest VDOT; a training run you didn’t race all-out will read low. Races from 5K to the half marathon tend to give the most reliable score for most runners.
Why are the equivalent times only a prediction?
Equivalent times assume the same fitness transfers perfectly across distances, which it rarely does — endurance, fuelling, heat and course all matter. Treat them as well-calibrated targets that reward the right training, not guarantees. For a model comparison (Riegel, Cameron, VDOT) use the race-time predictor.
How do I turn my VDOT into training paces?
Daniels assigns easy, marathon, threshold, interval and repetition paces to each VDOT. This page focuses on your score and equivalent race times; for the workout paces themselves, use a training pace calculator.
My VDOT looks low — is something wrong?
Usually it means the race you entered wasn’t a true all-out effort, the distance or time was off, or you were tired or running in heat. Enter your best recent race on a fair course. VDOT improves with training, so a lower number today is simply your starting point.
VDOT and the equivalent times are mathematical estimates from a published model (Daniels & Gilbert), not a measured VO₂max or a personalised race plan. General information for training, not medical or coaching advice.