Longevity calculator
Fitness age calculator — from a VO₂ max you already have
Enter a VO₂ max and this finds the age at which that value is the population median for your sex. It is a lookup against a reference curve, not the non-exercise questionnaire most fitness age calculators use — see below, because the difference matters. Free, instant, no sign-up.
Quoted to one decimal because the norms are decade buckets. The decimal is interpolation between bucket centres, not measured resolution.
The curve your value was read against
| Age band | 40th percentile | 60th percentile | Estimated median |
|---|---|---|---|
| 20-29 | 41.7 | 45.4 | 43.55 |
| 30-39 | 40.5 | 44 | 42.25 |
| 40-49 | 38.5 | 42.4 | 40.45 |
| 50-59 | 35.6 | 39.2 | 37.4 |
| 60-69 | 32.3 | 35.5 | 33.9 |
| 70-79 | 29.4 | 32.3 | 30.85 |
The source table has no median column. Each median here is the midpoint of the published 40th and 60th percentiles, which under a normal distribution is the median exactly — those two percentiles sit at z = −0.253 and +0.253, symmetric about zero.
A number off a curve is a starting point. What raises it over the next three months is a training question, and the coach works from the week you actually run.
What this calculator returns
The age at which your VO₂ max is the estimated median for your sex. If a 52-year-old man enters 44 ml/kg/min and the answer is 33, the sentence that follows is "this VO₂ max is typical of a 33-year-old in the reference population" — nothing more. A fitness age is a percentile lookup wearing a year as a unit. It is not a prediction of anyone's lifespan, and aerobic fitness tracking mortality strongly in the literature does not turn this number into a personal forecast.
This is not the NTNU/HUNT fitness age
The version most calculators reproduce is the non-exercise model from Nes and colleagues (Med Sci Sports Exerc, 2011), which predicts VO₂peak from age, waist, resting heart rate and a physical activity index — no test required. That model was not used here, for a specific reason: its regression coefficients are behind a paywall, the versions circulating on calculator sites disagree with each other, none of them states how the activity index is coded, and none cites the curve that turns a predicted VO₂peak into an age. Shipping coefficients that cannot be checked against the paper produces a confident number with nothing underneath it. So this tool asks for the VO₂ max instead of guessing at it. If you came here for the questionnaire version, this is a different thing and you should know that before you read the result.
How the lookup works
The Cooper Institute / ACSM normative table publishes four cut-points per age band and sex: the 40th, 60th, 80th and 95th percentiles. Averaging the 40th and 60th gives an estimated median for each of the six bands, and joining those six points gives a curve that decreases with age for both sexes — which is what makes the inverse lookup well defined. Your VO₂ max lands between two of those medians, and the answer is the age where the curve crosses your value, by linear interpolation between the two band midpoints.
When it returns no age at all
The curve spans only the ages the norms are published for. A VO₂ max above the median of the 20–29 band means you are aerobically fitter than the median twenty-something; how much younger than twenty that makes you is not a question the table can answer. The same applies below the 70–79 median at the other end. In both cases this page says so rather than extrapolating past the last published point. Most calculators extend the line and return a number anyway.
What the reference population is
The curve inherits every limit of the table it comes from: a cohort of mostly white, college-educated American volunteers who were healthy enough to take a maximal treadmill test, bucketed into decades, with the median itself estimated rather than published. Anchoring at band midpoints means the curve describes decade averages — real VO₂ max does not decline in a straight line between age 24.5 and age 34.5. Treat the answer as a comparison against that specific group of people, which is all any fitness age has ever been.