How old is your body, really?
Answer a few everyday questions and get your fitness age — a kind, science-based read on your heart-and-lung fitness, expressed as a single number. No verdicts, no shame. Just one number you can move.
Add hips and we’ll also show your waist-to-hip ratio — a separate body-composition signal that doesn’t change your fitness age.
Garmin, Apple Watch and Whoop all estimate it. Enter it — or a Cooper 12-minute run distance — for a more accurate result. Otherwise we’ll estimate from your answers above.
Worked out in your browser. Nothing is saved and nothing is shared unless you choose to.
Your fitness age is built from your estimated VO₂max — the single best-validated marker of cardiorespiratory fitness. We use the peer-reviewed HUNT-study non-exercise model (Nes et al., 2011) to estimate it from everyday inputs, then express it as the age at which that fitness level is average. If you know your measured VO₂max or a Cooper-test distance, pop it in and we use that instead.
It is an estimate, not a lab test — treat it as a ballpark and a starting point. The reliable version is a full assessment with a trainer.