How metabolic age is inferred
We estimate your BMR with Mifflin-St Jeor, then compare it to the same equation at a BMI-22 reference weight for your height, sex, and age. Quiz answers then shift that compared burn: lifting most weeks (+6%), short sleep (−4%), a moderate cut (−3%), or a hard cut (−8%). Higher than typical → “younger,” similar, or “older.” Labels only.
Typical = same formula at BMI 22 for your height
Compared burn = Mifflin × (1 + quiz shift)
Why formulas disagree
Harris-Benedict, Katch-McArdle, and devices all disagree. None of them is a lab metabolic age. Extra fat can raise BMR and look “younger” on this chart — that’s a limitation, not a flex.
What actually moves the number
Lean mass, consistent eating, and sleep. Crash dieting can pull measured burn down. Toggle the quiz answers above and the younger / similar / older label moves. We do not claim this reverses aging. Daily calories with activity belong on the TDEE calculator.
Not medical advice
This tool is for education and planning. It does not diagnose, treat, or replace care from a qualified professional.
Want the daily picture?
Log meals and hit the target with CaloDrop.
What moves the number is muscle, food, and sleep — logged meals beat a birthday on a chart.