VO2 Max Calculator

What VO2 max is

VO2 max is the most oxygen your body can use per minute, per kilogram of body weight (ml/kg/min). It sets a ceiling on aerobic performance. Two runners with the same VO2 max can still race very differently, because running economy and how close to that ceiling you can hold for an hour or more matter just as much.

How the race estimate works

The race method uses the equations Jack Daniels and Jimmy Gilbert published: first the oxygen cost of running at your average speed, then the share of your maximum a runner can hold for that long. Dividing one by the other gives the estimate, often called VDOT. It assumes an all-out effort on a flat course, so a hilly, hot or easy-paced race gives a low number.

How the heart-rate estimate works

The heart-rate ratio method is 15.3 × max heart rate ÷ resting heart rate. It is quick, but it depends heavily on a true maximum. An age formula such as 220 minus age can be off by 10 beats or more, which moves the result a lot. Use it as a rough starting point and prefer the race method when you have a recent result.

What to do with the number

• Track the trend, not the value. Re-test with the same kind of race every couple of months.
• Turn the race into goals and paces instead: the race time predictor gives finish times for other distances and the pace calculator turns a goal into splits.
• Train mostly easy. Most VO2 max gains for runners come from consistent aerobic volume, with a little hard work on top. Our Zone 2 guide explains why.

These are population formulas that give estimates, not a lab test or medical advice. If you have a heart condition, take medication that affects heart rate, or have symptoms during exercise, talk to a qualified clinician before testing at maximum effort.