Three ways to estimate it (they don’t agree)
- Heart-rate ratio (Uth, 2004):
15.3 × HRmax ÷ HRrest. Needs your maximum and resting heart rate. - 12-minute run (Cooper):
(metres run − 504.9) ÷ 44.73. Needs the distance you cover in 12 minutes. - 1-mile walk (Rockport): a regression on weight, age, sex, walk time and finishing heart rate.
Each uses different inputs, so the calculator picks the method that fits what you’ve entered — and shows the spread when more than one is available.
Why these are estimates, not measurements
Field estimates typically sit within ±10–15% of a lab value, and the gold standard is a graded exercise test with gas analysis. Two method-specific cautions worth knowing:
- The heart-rate ratio (Uth) was calibrated on trained adults — outside that group (untrained people, and women in particular) it tends to be biased, so treat its number with extra caution if that’s you.
- The 1-mile walk (Rockport) formula uses a binary sex term (1 or 0). That’s baked into the 1987 regression it comes from — it isn’t something we can “improve” by substituting, because that would take the formula outside where it was validated. We keep it as published and flag it here rather than pretend otherwise.
Sources: Uth N, Sørensen H, Overgaard K, Pedersen PK. Eur J Appl Physiol. 2004;91(1):111–115. Cooper KH. JAMA 1968;203(3):201–204. Kline GM et al. Med Sci Sports Exerc. 1987;19(3):253–259.
FAQ
What is VO₂max?
It’s the maximum amount of oxygen your body can use per minute during hard exercise, usually in millilitres per kilogram per minute (ml/kg/min). It’s the standard yardstick for aerobic (cardio) fitness — higher generally means a bigger aerobic engine.
Can I estimate VO₂max without a lab?
Yes, approximately. This calculator uses three published field methods — a heart-rate ratio, a 12-minute run and a 1-mile walk — each needing inputs you can gather yourself. They’re estimates within roughly ±10–15% of a lab test, so we show a range, not one exact figure.
What is a good VO₂max?
It varies with age and sex, and “good” is relative to you. Rough adult ranges run from the high 20s (lower fitness) to the 50s and above (well-trained endurance athletes), declining gradually with age. Your own trend over months tells you more than any single benchmark.
Why do the methods give different numbers?
Because each was built on a different test, population and set of assumptions. The heart-rate ratio was calibrated on trained adults; the walk and run tests infer VO₂max from performance under their own conditions. A number with no method attached is ambiguous, so we label each and show the spread.
How accurate is an estimated VO₂max?
Field estimates are typically within ±10–15% of a laboratory measurement, which is enough to track change over time but not to compare people precisely. For a measured value, a graded exercise test with gas analysis is the reference standard.