Adjusted Ideal Body Weight Calculator

About this calculator

Adjusted body weight (AdjBW) is a clinical dosing weight used when a patient’s actual weight is significantly above their ideal weight, since dosing purely on actual weight can overestimate the dose for drugs that distribute mainly into lean tissue. It starts from the Devine formula for ideal body weight — IBW (kg) = 50 + 2.3 × (height in inches − 60) for men and 45.5 + 2.3 × (height in inches − 60) for women — and then applies a correction: AdjBW = IBW + 0.4 × (actual weight − IBW).

The 0.4 correction factor reflects the observation that excess adipose tissue is not metabolically inert but also isn’t as pharmacologically active as lean mass, so adjusted body weight sits between the two extremes of using actual weight or ideal weight alone. Pharmacists, dietitians and clinicians use AdjBW for dosing certain medications and nutritional calculations in patients with obesity; enter height, weight and sex to estimate it. Not medical advice.