Ideal Weight Calculator

All four were derived independently in different decades from different populations. Hamwi (1964) was developed for medication dosing in diabetes management (American Diabetes Association). Devine (1974) refined it for gentamicin dosing in renal-impaired patients. Robinson (1983) and Miller (1983) were validation studies in American Journal of Hospital Pharmacy 40 — Robinson averaged published equations, Miller proposed a smoother curve. Showing all four lets you see the ±2-3 kg variation between formulas at the same height and gives you a sensible range rather than a falsely precise number.

It's a clinical heuristic, not a biological truth. The original purpose (Hamwi 1964, in Danowski's Diabetes Mellitus textbook) was to provide a reference weight for calculating medication doses — particularly aminoglycoside antibiotics and other drugs with narrow therapeutic windows where dosing by total body weight risks toxicity in obese patients. 'Ideal weight' became a way to dose for the lean-body-mass equivalent. Devine's 1974 reformulation (Drug Intelligence and Clinical Pharmacy 8(11):650-655) for gentamicin made the concept widely used in hospital pharmacy.

All four are heuristics derived from limited population data — none is 'most accurate' for individual body composition because they aren't measuring composition, just height-based weight reference. Hamwi 1964 is the original (most generous), Devine 1974 is slightly tighter, Robinson 1983 averages prior equations, Miller 1983 smooths the curve at extremes. The 2-3 kg spread between formulas reflects which population data each was fit to, not biological truth. Use the average as a rough reference; don't treat any single formula as the 'right' answer.

Validity ranges are limited. The original Hamwi/Devine formulas were derived from adult populations approximately 5'-6' (152-183 cm). For people significantly outside this range — very tall (>2 m), very short (<1.50 m), achondroplasia or other proportional differences — the formulas extrapolate poorly. The body composition implied by 'ideal weight' doesn't scale linearly with height. For atypical body geometry, body fat percentage or BMI-based reference ranges are more meaningful than these height-based formulas.

BMI cutoffs for general health, body fat percentage reference ranges for body composition, and waist-to-height ratio for cardiovascular risk all replace ideal weight in modern clinical practice. The 'ideal weight' concept survives in pharmacy (medication dosing) but has been deprecated for body composition or weight-loss goals — it's a 60-year-old heuristic, not a target. For weight management goals, the calorie calculator + body fat calculator give more actionable information than a single ideal-weight number.