BMI, BSA & Ideal Body Weight
Body Mass Index, Mosteller/DuBois BSA, Devine IBW and Adjusted Body Weight.
Switch how results are explained
Normal body weight (BMI 18.5–24.9 kg/m²). Encourage healthy lifestyle and balanced nutrition.
- Evidence grade
- A
What it is and when to use it
The Body Mass Index (BMI) categorizes weight status, while Body Surface Area (BSA via Mosteller and DuBois) and Ideal/Adjusted Body Weight (IBW/ABW via Devine) are widely used for chemotherapy, renal drug dosing, and clinical nutrition.
How to interpret it
BMI <18.5 is underweight, 18.5–24.9 is normal weight, 25.0–29.9 is overweight, and ≥30.0 indicates obesity. BSA and IBW assist in accurate therapeutic dosing.
Limitations and when not to use it
BMI does not differentiate muscle mass from adipose tissue and may misclassify athletic individuals or elderly patients with sarcopenia.
Formulas and cut-offs are from the original authors of each score; see the references.
Last reviewed: June 2026
References
- Mosteller RD. Simplified calculation of body-surface area. N Engl J Med. 1987;317(17):1098. PMID:3657876
- Devine BJ. Gentamicin therapy. Drug Intell Clin Pharm. 1974;8:650-655.