ideal body weight formulas
"Ideal weight" is not a single number: it is four formulas from different decades, originally built for medication dosing and clinical planning, not as an aesthetic target, and each one calculates its own result for the same height and sex.
The 5.8 kg gap between the lowest formula (Miller) and the highest (Hamwi) shows why the result is usually presented as a range, not a single closed number.
The range here is narrower, from 56.4 kg to 59.8 kg, because the female coefficients of the four formulas diverge less from each other than the male ones do at this height.
Below 1.52 m the height term stops subtracting anything, so a person at 1.30 m gets exactly the same four values as one at 1.45 m, a structural limitation of the formulas, not a rounding error.
Not as a universal number. The term is historical and oversimplifies health.
Because each one was fitted in a different decade and population sample (Hamwi in 1964, Devine in 1974, Robinson and Miller in 1983), with its own coefficient per inch of height above 1.52 m; there is no fifth formula that arbitrates between them, which is why the result is usually shown as a range.
That is not their origin: these formulas were built for clinical use, mainly to calculate medication dosing by body weight, not as an aesthetic or weight-loss goal. The number is a reference convention, and any individual weight target is a decision for a health professional.
The Devine formula, published in 1974, is the one most cited in clinical pharmacology to estimate the body weight used for dosing calculations of certain medications, a use distinct from any personal weight goal.
Below 1.52 m, not proportionally: the height term in all four formulas locks at zero at that point, so any shorter height receives the same base weight with no differentiation, which shows they were calibrated for adult heights at or above 1.52 m.
Medical disclaimer: ideal weight is a historical and limited concept. Do not use it as a diagnosis, mandatory target or health assessment without professional care.
| Formula | Estimate |
|---|---|
| Devine | 56.9 kg |
| Robinson | 57.4 kg |
| Miller | 59.8 kg |
| Hamwi | 56.4 kg |
The formulas use height and binary coefficients. They do not consider body composition, age, ethnicity, clinical history or personal context.
Historical adult formulas by height above 5 ft; values in kg.
Height and selection stay in your browser and are not sent to analytics.