Commonly used in clinical drug dosing. Based on the Devine formula (1974).
Source: Devine, Drug Intell Clin Pharm 1974.
What does ideal body weight mean?
Ideal body weight (IBW) as calculated by the Devine formula is a clinical estimate of the weight at which a person of a given height is expected to have optimal lean body mass relative to height. It was developed by Dr B.J. Devine in 1974 primarily for calculating appropriate drug doses, particularly for medications that distribute into lean rather than fat tissue.
The formula is straightforward: for men, IBW = 50 kg + 2.3 kg for every inch over 5 feet; for women, IBW = 45.5 kg + 2.3 kg for every inch over 5 feet. The formula was empirically derived, not based on population health outcomes, which means it should not be interpreted as a personal weight goal.
Several alternative IBW formulas exist, including Robinson (1983) and Miller (1983), which produce slightly different values. For patients who are significantly overweight, clinicians often use Adjusted Body Weight (ABW = IBW + 0.4 × (actual weight − IBW)) for drug calculations. The Devine formula remains the most widely cited in clinical practice.
From a health perspective, the weight range associated with lowest mortality spans a BMI of roughly 18.5–24.9. For most adults of average frame, the Devine IBW lands within this BMI range, which is why the two metrics often agree, but neither should be treated as a strict personal target without clinical context.
Reference ranges
| Height | IBW — Men (kg) | IBW — Women (kg) |
|---|---|---|
| 160 cm (5′3″) | 52.7 | 48.2 |
| 165 cm (5′5″) | 55.0 | 50.5 |
| 170 cm (5′7″) | 57.3 | 52.7 |
| 175 cm (5′9″) | 59.5 | 55.0 |
| 180 cm (5′11″) | 61.8 | 57.3 |
| 185 cm (6′1″) | 64.1 | 59.5 |
When should you see a doctor?
Ideal body weight calculations are often referenced in clinical settings for medication dosing and nutritional planning. If you are considering using IBW to set a weight-loss target, speak with a doctor or dietitian first, individual variation in healthy weight is substantial, and IBW can underestimate a healthy weight for muscular individuals and overestimate it for smaller-framed people.