Your race time is the best free predictor of running VO2 max. Enter a recent 5K, 10K, half, or marathon result and we estimate it with Jack Daniels' VDOT formula — plus the five training paces that go with it.
Daniels VDOT method
Enter a recent race result
Estimated VO2 max (VDOT)
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Enter a race result above to estimate your VO2 max.
Approximate “good” ranges for healthy adults, in ml/kg/min. Regular runners usually sit at or above the top of their range; elite distance runners measure 70–85.
| Age | Men | Women |
|---|---|---|
| 20–29 | 44–51 | 39–45 |
| 30–39 | 41–48 | 37–42 |
| 40–49 | 39–45 | 33–38 |
| 50–59 | 36–41 | 30–35 |
| 60+ | 33–37 | 27–32 |
VO2 max is the maximum rate at which your body can take in and use oxygen, measured in millilitres of oxygen per kilogram of body weight per minute (ml/kg/min). It sets the ceiling of your aerobic engine: the higher it is, the faster you can run aerobically. For endurance runners it is one of the three big performance factors alongside lactate threshold and running economy.
Your race performance already reflects your oxygen capacity. This calculator uses Jack Daniels' VDOT formula, which combines the oxygen cost of your race pace with the percentage of VO2 max you can sustain for the race duration. Because it is derived from what you actually ran — not just heart rate or wrist data — it is one of the most practical estimates available outside a lab.
It depends on age and sex. As a rough guide, 44–51 is good for men in their 20s and 39–45 for women in their 20s, declining gradually with age. Recreational runners typically sit in the high 30s to low 50s, serious club runners in the 50s and 60s, and elite distance runners measure 70–85.
VDOT is Jack Daniels' 'effective VO2 max' — a single number that bundles true VO2 max together with running economy and fatigue resistance, because it is derived from race performance. Two runners with identical lab-measured VO2 max can have different VDOTs if one converts oxygen into speed more efficiently. For setting training paces, VDOT is actually more useful than the lab number.
Watch estimates are based on heart rate against pace and typically land within 5–10% of a lab test, but they drift with heart-rate sensor errors, heat, and terrain. A race-result estimate like this one reflects what you can actually sustain in competition, which is usually a better anchor for training paces than the day-to-day watch number.
Interval training at 95–100% of VO2 max effort gives the strongest stimulus: classic sessions are 4–6 × 3–5 minutes (or 1000–1200 m repeats) at your Interval pace from this calculator, with similar-length jog recoveries. Consistent easy mileage also raises it over time by building cardiac stroke volume and capillary density. Most runners see the fastest gains from adding one interval session per week to a solid easy base.
Re-estimate whenever you set a meaningful new race result, or every 6–8 weeks during a training block using a 5K time trial. Update your training paces to the new VDOT — training to outdated paces is a common way to under- or over-train.