VO₂ Max Calculator
VO₂ max is the maximum rate at which you can use oxygen — the standard measure of aerobic capacity. A field test estimates it; only a lab can measure it.
Your results
A field-test estimate, not a laboratory measurement. Different methods routinely disagree by 5–8 ml/kg/min for the same person, so compare a method only against itself over time.
The three methods, and why they disagree
- Cooper 12-minute run. The classic field test: VO₂max = (metres − 504.9) ÷ 44.73. Simple, and it tends to read on the high side. Requires a genuinely maximal effort, which is hard to pace.
- Daniels' VDOT from a race. Uses a running-economy curve and the fraction of VO₂ max sustainable for a given duration. The most reliable of the three if you have a recent race result, and it matches published VDOT tables closely.
- Resting heart rate ratio. VO₂max ≈ 15.3 × (maxHR ÷ restingHR). Requires no exercise and is much cruder — it uses only two heart-rate numbers and ignores your actual performance entirely.
Expect these to differ. That is not a flaw in one of them; it reflects that VO₂ max is being inferred from indirect evidence.
What VO₂ max does and does not predict
It is a strong marker of cardiorespiratory fitness and one of the better predictors of all-cause mortality risk in population studies. Improving it is genuinely worth doing.
It is a weaker predictor of race performance than people assume. Two runners with identical VO₂ max can differ substantially over 10 km because of running economy, lactate threshold and the fraction of maximum they can sustain. That is why Daniels' model works from performance rather than from a lab number.
And it says nothing about strength, muscle mass or body composition. A very strong lifter can have an unremarkable VO₂ max and vice versa.
Common questions
What is a good VO₂ max?
For men roughly 41–46 is fair to good and 53+ is superior; for women 35–39 fair to good and 45+ superior. Bands shift with age.
How accurate are VO₂ max estimates?
Field tests are typically within 10–15% of a laboratory value. Different methods disagree by more than that between themselves.
Is my watch's VO₂ max accurate?
Directionally useful at best. It infers from heart rate and pace, and it is sensitive to heart-rate accuracy.
How do I improve VO₂ max?
A mix of large volumes of easy aerobic work and a smaller amount of hard interval work near maximum. Both matter.
Related calculators
Track the numbers, not just calculate them
MyFitsy stores your weight, measurements and every session, so the figures above become a trend instead of a one-off.
