The ideal body weight formulas
Each formula starts from a base weight at 5 feet (152.4 cm) and adds a fixed amount for every inch above that height:
| Formula | Men | Women |
|---|---|---|
| Devine (1974) | 50.0 kg + 2.3 kg per inch | 45.5 kg + 2.3 kg per inch |
| Robinson (1983) | 52.0 kg + 1.9 kg per inch | 49.0 kg + 1.7 kg per inch |
| Miller (1983) | 56.2 kg + 1.41 kg per inch | 53.1 kg + 1.36 kg per inch |
| Hamwi (1964) | 48.0 kg + 2.7 kg per inch | 45.5 kg + 2.2 kg per inch |
Example: a man who is 180 cm (about 70.9 inches) tall is 10.9 inches over 5 ft. Devine gives 50 + 2.3 × 10.9 ≈ 75 kg.
Why FitNumbra shows a range first
These formulas were developed to estimate medication doses, not to set personal weight goals. They ignore muscle, frame size, age and body shape, and they give quite different answers for the same person. The BMI-based healthy range is broader and reflects the fact that healthy bodies come in different shapes.
How to use your result
- Use the healthy range as a broad guide, not an exact goal.
- If you strength-train, a weight near or even above the upper limit can be healthy — the body fat calculator gives extra context.
- Speak to a healthcare professional before starting a significant weight-change plan.
Frequently asked questions
What is my ideal weight?
There is no single ideal weight. A healthy weight range based on BMI 18.5–24.9 is a more realistic guide, and the classic formulas give a rough point estimate within or near that range.
Which ideal weight formula is most accurate?
None is clearly best for individuals. Robinson and Miller tend to give slightly different results from Devine and Hamwi. They were designed for medication dosing, so treat them as rough references only.
Why are the formulas not shown for my height?
The formulas add weight for each inch above 5 feet, so they are not valid for adults shorter than 5 feet (152 cm). The BMI-based range still applies.
Methods and sources
- Devine BJ. Gentamicin therapy. Drug Intell Clin Pharm. 1974;8:650–655.
- Robinson JD, et al. Determination of ideal body weight for drug dosage calculations. Am J Hosp Pharm. 1983;40:1016–1019.
- Miller DR, et al. Determining ideal body weight (and mass). Am J Hosp Pharm. 1983;40:1622–1625.
- World Health Organization — Obesity and overweight fact sheet (BMI classification) (opens in a new tab)
Content reviewed: by the FitNumbra editorial team.