Formula Governance
Healthy Weight Range Calculator — Change Log
Every formula on HealthCalcNow is version-controlled. This page records the formula behind the Healthy Weight Range Calculator — its current version, the source it comes from, and any revision made since publication.
Current version
Reference. WHO BMI classification (see BMI); WHO Expert Consultation Asian cutoffs, The Lancet, 2004
Why this confidence level. Direct derivation from the population-validated WHO BMI cutoffs; carries BMI’s caveat (does not account for muscle mass/build).
Revision history
How we version formulas
A calculator's math lives in an isolated module with its own version number. Changing anything that affects a result — a coefficient, a category cutoff, a rounding rule, or the cited source — requires a version bump and an entry on this page. We don't silently edit formulas.
A last-reviewed date is different from a revision: it records when we last checked the formula against its published source and confirmed it still matches. A formula can be reviewed many times without changing.
We take our values from published public-health and scientific sources rather than deriving them ourselves, and we don't claim clinician review that hasn't happened. Read more in our methodology.