About this tool
The VO2 Max Calculator is a free, in-browser tool that estimates your maximal oxygen uptake (VO2 max, in ml of oxygen per kg of body weight per minute) — the standard measure of aerobic fitness — using two published field methods.
The Cooper method converts the distance you can run in 12 minutes with VO2max = 22.351 × km − 11.288. The heart-rate method (Uth–Sørensen) needs no exercise test at all: VO2max = 15.3 × HRmax ÷ HRrest. Both are estimates of a value that can only be measured precisely in a lab with gas-exchange analysis; all math runs locally in your browser.
Frequently asked questions
How do I do the Cooper test?
Warm up, then run or walk as far as you can in exactly 12 minutes on a flat course or track, and enter the distance in metres. The formula VO2max = 22.351 × km − 11.288 was validated against lab measurements by Kenneth Cooper in 1968.
How does the resting heart rate method work?
The Uth–Sørensen formula VO2max = 15.3 × HRmax ÷ HRrest uses the ratio of maximum to resting heart rate. Measure HRrest after waking before getting up; if you don't know HRmax, 220 − age is a common rough estimate.
What is a good VO2 max?
It depends strongly on age and sex. As a broad adult guide: under 30 is low, 30–40 fair, 40–50 good, 50–60 very good and above 60 excellent — elite endurance athletes reach 70–90. The rating shown here is a general adult band.
How accurate are these estimates?
Both formulas carry roughly ±10% error versus a lab test, and they run entirely in your browser with nothing uploaded. They are fitness estimates, not medical measurements — do not use them to make health decisions.