VO2 Max Calculator: Estimate Your Cardiorespiratory Fitness Score

If you've ever seen a "VO2 Max" number pop up on your Apple Watch, Garmin, or Whoop and wondered what it actually means, you're not alone. It's one of the most searched fitness metrics online, and for good reason. VO2 max is the single number that tells you how efficiently your heart, lungs, and muscles work together under maximum effort.
Our VO2 max calculator gives you a fast, evidence-based estimate of your cardiorespiratory fitness using a validated non-exercise or Cooper test formula, so you don't need a lab, a mask, or a treadmill to get a useful starting number.
Below, you'll find the formula behind the calculator, a step-by-step breakdown of how to calculate VO2 max yourself, and guidance on interpreting your score against normative charts for your age and sex.