Ideal Body Weight & Adjusted Body Weight

Devine formula from height and sex; optional actual weight for adjusted body weight in obesity.

Calculator

Height (cm)

Sex (for Devine formula)

Male Female

Actual body weight (kg, optional)

Height 100–250 cm. If you enter weight and it exceeds IBW, adjusted weight uses a common 40% factor on excess mass (institutions vary 25–50%).

Results

How it works

What this tool does

It estimates Devine ideal body weight and, when actual weight exceeds IBW, a commonly taught adjusted weight for medication dosing in obesity.

Formulas (this page)

Height in inches = cm ÷ 2.54. Inches over 60 = max(0, inches − 60). Male IBW (kg) = 50 + 2.3 × inches over 60. Female IBW (kg) = 45.5 + 2.3 × inches over 60. If actual weight > IBW: Adjusted BW = IBW + 0.4 × (actual − IBW).

References

Devine BJ. Gentamicin therapy. Drug Intell Clin Pharm. 1974;8(11):650-655. (Commonly cited IBW derivation.)

Dosing & care

Teaching notes

Adjusted body weight is used for some renally cleared drugs and chemotherapy contexts; it is not universal.
Some references use BMI-based IBW or different obesity adjustment factors.

Limitations

Does not model amputations, fluid overload, pregnancy, or pediatric-specific rules; not every drug should use IBW or adjusted weight.

Dosing context (teaching)

Confirm each medication’s labeled or institutional weight basis (total, IBW, adjusted, or capped).
Renal function estimates (e.g., Cockcroft-Gault) may also specify which weight to enter—keep methods consistent.
Pharmacist review remains standard for high-risk narrow therapeutic index drugs.

Educational tool only—not for diagnosis or treatment decisions.