Calculate ideal body weight using Devine, Robinson, Miller, and Hamwi formulas with healthy BMI range comparison.
Four historical formulas dominate ideal-body-weight literature. All four follow the same shape — a base weight at 5 ft plus a per-inch increment — but disagree on the slope and the baseline. The calculator shows all four so you can see the spread, then averages them and compares against the WHO healthy BMI range, which is the modern reference most clinicians cite.
Published by Robinson et al. as a refinement over Devine. The gentler slope produces lower estimates for tall people, which more modern body-composition work tends to prefer. Still widely used in renal dosing and anaesthesia references.
Miller's equation has the flattest slope, so it under-predicts for tall people relative to the others. It has the highest baseline though, so short people get a higher number. Prefer this one if you're near average height; expect disagreement at the extremes.
Originally derived for drug-dosing, not clinical weight targets. It was never meant as a body-image metric — Devine himself cautioned against that use. Dominant in pharmacology textbooks, which is why it still appears everywhere decades later. Tends to over-predict for very short people.
The original — proposed for calculating insulin doses in diabetic patients. The steepest slope for men means the tallest estimates for tall men, often seen as too generous by modern standards. Included here for completeness and historical context.
Why show all four? They disagree by 3–6 kg for an average adult and more at the extremes, which is informative in itself: there is no single "correct" ideal weight. A healthy range derived from BMI 18.5–24.9 is wider than any single formula's output and is what public-health guidance actually uses. Muscle mass, age, sex-related fat distribution, and ethnicity all shift the practical target — treat the numbers on this page as a starting point for a conversation with a clinician, not a goal.
Each formula was developed independently using different study populations and methodologies. Devine's was designed for drug dosing, while others were clinical estimates. The variation reflects the difficulty of defining a single 'ideal' weight for any height.
No single formula is universally most accurate. The Robinson formula is often considered the best general revision of Devine's original. However, the average of all four gives a reasonable middle estimate. For personalized guidance, consult a healthcare provider.