VO2max Calculator — Cooper 12-Minute Test

This free VO2max calculator estimates your aerobic fitness from the classic Cooper 12-minute test — run or walk as far as you can in 12 minutes. Enter your distance, age, and sex to get an instant VO2max estimate in ml/kg/min, your fitness rating against Cooper norms for your age group, and a rough 5K potential. Everything recalculates instantly as you type.

How to use this calculator

First take the test: warm up for 5–10 minutes, then run or walk as far as you possibly can in exactly 12 minutes on a flat track, course, or treadmill. Walking breaks are allowed — the original Cooper test permits any mix of running and walking. Measure the total distance you covered, in meters or miles.

Enter that distance, your age, and your sex above — use the Meters/Miles toggle to match your measurement. Results update instantly: your estimated VO2max, your fitness rating (Superior through Poor) against Cooper norms for your age group and sex, and a rough 5K potential.

To track progress, retest every 6–8 weeks under the same conditions — same surface, similar weather, same effort. Improvements of 1–3 ml/kg/min per training cycle are realistic for most runners. Pair your result with the heart rate zone calculator to set training intensities, and the calories burned calculator to estimate what your sessions cost.

How it works

This calculator uses the published Cooper formula for the 12-minute run test:

VO2max = (distance in meters − 504.9) / 44.73

The result is in milliliters of oxygen per kilogram of body weight per minute (ml/kg/min) — the standard unit of VO2max. For example, covering 2,400 m in 12 minutes gives (2,400 − 504.9) / 44.73 = 1,895.1 / 44.73 = 42.37 ml/kg/min. If you enter miles, the distance is first converted to meters (1 mile = 1,609.344 m). Distances at or below 504.9 m are outside the formula's valid range, so the calculator flags them instead of reporting a meaningless or negative number.

Your fitness rating compares that estimate to the Cooper Institute norms for your age band and sex. Because VO2max naturally declines with age and differs by sex, the same number means different things for different people — 42 ml/kg/min is Superior for a 55-year-old man but only Good for a 25-year-old man. The full reference table appears under your results, with your age band highlighted.

The rough 5K potential is worked backward from your VO2max using the Daniels-Gilbert running equations — the same VDOT system coaches use to predict race times. It assumes race fitness roughly equal to your test effort, which often is not true, so treat it as a very rough ballpark, not a prediction you should race to.

Important: this is an estimate, not a lab measurement of VO2max, and it is not medical or exercise advice. A maximal 12-minute effort is strenuous — if you are new to exercise, have a heart condition, feel chest pain, or take medication that affects exercise capacity, talk to a doctor or qualified professional before taking the test.