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.
Frequently asked questions
What is the Devine formula for ideal body weight?
The Devine formula (1974) estimates ideal body weight (IBW) based on height and sex. For men: IBW (kg) = 50 + 2.3 × (height in inches − 60). For women: IBW (kg) = 45.5 + 2.3 × (height in inches − 60). It was originally developed to adjust drug doses and was not intended as a weight-loss target.
Should I try to reach my ideal body weight?
Not necessarily. The Devine IBW is a clinical calculation used for drug dosing and nutritional formulas, not a personal weight-loss goal. A person can be perfectly healthy at a weight that differs substantially from their IBW. Healthy weight targets are best determined by a clinician considering your full metabolic profile, not a formula alone.
Why is IBW used in drug dosing?
Many drugs distribute primarily in lean body tissue rather than fat. Using actual body weight for obese patients would result in dangerously high doses. IBW (or adjusted body weight, which is a blend of IBW and actual weight) provides a more accurate estimate of lean mass for dose calculations of drugs like aminoglycosides and certain chemotherapy agents.