Dosing & Body Metrics
Body size decides the dose for a large share of drugs, and the choice between total, ideal, and adjusted body weight can change that dose substantially. These calculators cover body mass index, ideal body weight by the Devine equations, adjusted body weight, and body surface area by Mosteller with Du Bois shown alongside for comparison. A dedicated dosing-weight tool addresses the question the others raise but do not answer: for this drug and this patient, which weight belongs in the equation.
Body mass index (BMI)
Calculate body mass index from height and weight and classify it against the WHO categories.
Ideal body weight (Devine)
Calculate ideal body weight from height and sex using the Devine equations, with adjusted body weight and percentage of IBW alongside.
Adjusted body weight (AdjBW₀.₄)
Calculate adjusted body weight, the weight used for hydrophilic drugs such as aminoglycosides in obese patients.
Body surface area (Mosteller & Du Bois) High-risk
Calculate body surface area by the Mosteller equation, with the Du Bois equation shown for comparison.
Which weight to use for dosing High-risk
Determine whether a given drug should be dosed on total, ideal, or adjusted body weight for a specific patient, and return the resulting dosing weight.
High-consequence calculations in this group
These carry a greater risk of harm if the result is wrong or misapplied. Each states its own limits on its page; read them before acting on a number.
- Body surface area (Mosteller & Du Bois) — Calculate body surface area by the Mosteller equation, with the Du Bois equation shown for comparison.
- Which weight to use for dosing — Determine whether a given drug should be dosed on total, ideal, or adjusted body weight for a specific patient, and return the resulting dosing weight.
Guides for this category
Where to go next
- Guides — longer explanations of how to work through a calculation and how to choose between related calculators.
- Practice problems — one worked problem for every calculator, solutions hidden until you open them.
- Reference tables and formula sheet — every constant and conversion factor used here, with citations.
- All 58 calculators — the full index, filterable by category.
Other categories
Also known as
BMI · body mass index · obesity · overweight · quetelet · IBW · ideal body weight · devine · lean weight · dosing weight · AdjBW · adjusted body weight · ABW · obesity dosing · aminoglycoside weight · BSA · body surface area · mosteller · du bois · chemotherapy · m2 · TBW IBW AdjBW · which weight · weight selection · aminoglycoside · acyclovir · theophylline