The four formulas
Each formula starts from a weight at 5 feet (60 in) and adds a fixed amount for every inch above that:
| Formula | Men | Women |
|---|---|---|
| Robinson (1983) | 52 kg + 1.9 kg per inch | 49 kg + 1.7 kg per inch |
| Miller (1983) | 56.2 kg + 1.41 kg per inch | 53.1 kg + 1.36 kg per inch |
| Devine (1974) | 50 kg + 2.3 kg per inch | 45.5 kg + 2.3 kg per inch |
| Hamwi (1964) | 106 lb + 6 lb per inch | 100 lb + 5 lb per inch |
Hamwi published his rule in pounds, so Calcist uses it in pounds. The others were published in kilograms. The healthy BMI range is 18.5 × height(m)² to 24.9 × height(m)².
Worked example
A man who is 5 ft 10 in is 10 inches over 5 feet:
Robinson: 52 + 1.9 × 10 = 71.0 kg (156.5 lb)
Miller: 56.2 + 1.41 × 10 = 70.3 kg (155.0 lb)
Devine: 50 + 2.3 × 10 = 73.0 kg (160.9 lb)
Hamwi: 106 + 6 × 10 = 166.0 lb (75.3 kg)
Miller: 56.2 + 1.41 × 10 = 70.3 kg (155.0 lb)
Devine: 50 + 2.3 × 10 = 73.0 kg (160.9 lb)
Hamwi: 106 + 6 × 10 = 166.0 lb (75.3 kg)
The healthy BMI range at that height is about 128.9 to 173.5 lb, which is much wider than the 11 lb spread between the formulas.
Why these are rough
- These formulas were made mainly to work out drug doses, not to set goal weights. Devine's, the best known, was published without supporting data.
- They ignore frame size, muscle, age and ethnicity.
- They're only defined for heights of 5 ft (152.4 cm) and over, so Calcist doesn't extend them below that.
- They're for adults 18 and over. For children and teens, the CDC uses BMI-for-age growth charts instead.
- A single "ideal" number can be misleading. Many weights within the healthy BMI range can be healthy, and a doctor or dietitian can help you think about yours.
Sources
- Pai MP, Paloucek FP. The origin of the "ideal" body weight equations. Ann Pharmacother 2000;34:1066–1069. — reviews where each formula came from.
- Robinson JD, Lupkiewicz SM, Palenik L, Lopez LM, Ariet M. Determination of ideal body weight for drug dosage calculations. Am J Hosp Pharm 1983;40:1016–1019.
- Miller DR, Carlson JD, Lloyd BJ, Day BJ. Determining ideal body weight (and mass). Am J Hosp Pharm 1983.
- Devine BJ. Gentamicin therapy. Drug Intell Clin Pharm 1974;8:650–655.
- Hamwi GJ. Therapy: changing dietary concepts. In: Danowski TS, ed. Diabetes Mellitus: Diagnosis and Treatment. American Diabetes Association; 1964:73–78.
- CDC: Adult BMI categories