Health and body metrics we measure
Written by The Kalcule Team · Last updated 18 août 2026
Weight, BMI, waist, body-fat estimates and lean-mass estimates are different lenses on the same body. This page is a map of those lenses and their failure modes.
Start with why you are measuring
Screening for population-level risk (BMI), tracking a cut (waist + photos + optional Navy fat), or programming training (strength logs plus lean-mass estimate) are different jobs.
Waist as a cheap extra
Waist circumference adds central-fat context that BMI lacks. WHO and national heart foundations publish cut-offs; they still are not diagnoses.
Do not collect every metric
Three good numbers beat twelve noisy ones. Obsession is a health outcome too.
Tools
BMI, body-fat and lean-mass calculators live in the fitness group on this site. Read limitations before you screenshot a result.
Questions Fréquemment Posées
Choosing a body metric.
There is no single best number. Match the metric to the question.
For a coarse trend, yes. For composition, no.
Daily weigh-ins show water noise. Weekly averages are calmer.
For weight, maybe. For BIA fat percentage, treat it as a noisy extra.
Vous avez encore des questions ?
Si vous n'avez pas trouvé la réponse que vous cherchiez, veuillez contacter notre équipe de support pour obtenir de l'aide personnalisée.