logo

Body Surface Area (BSA) Calculator

Calculate body surface area using Du Bois and Mosteller formulas. BSA is essential for accurate chemotherapy and immunosuppressant dosing. This calculator provides both standard formulas to help ensure proper pharmacotherapy dose calculations across patient populations.

Disclaimer: This tool is provided for informational and educational purposes only. Results should always be independently verified by a qualified healthcare professional before use in clinical practice. Compound Direct accepts no liability for errors or clinical decisions made based on these calculations.

How to Use This Tool

  1. Enter the patient's height in centimeters (cm)
  2. Enter the patient's weight in kilograms (kg)
  3. Click "Calculate BSA" or press Enter
  4. Both Du Bois and Mosteller formulas will be calculated automatically
  5. Use the BSA value appropriate for your institution's dosing protocols
  6. Verify height and weight are current and accurate before dose calculations

Formula & Methodology

Du Bois Formula

The Du Bois formula is one of the oldest and most widely recognized BSA calculations, developed in 1916. It is based on data from a limited number of subjects.

BSA (m²) = 0.007184 × height (cm)^0.725 × weight (kg)^0.425

Mosteller Formula

The Mosteller formula was developed in 1987 as a simpler alternative and is more accurate than Du Bois for children and obese patients. It uses a linear relationship and is easier to remember.

BSA (m²) = √(height (cm) × weight (kg) / 3600)

Clinical Use in Pharmacy

Body surface area is the primary dosing parameter for many chemotherapy agents and immunosuppressants. The choice between formulas may vary by institution and drug type:

  • Du Bois: Traditional standard, still used for many oncology protocols
  • Mosteller: Increasingly preferred due to improved accuracy in obese and pediatric patients

Why BSA Matters

Using body weight alone for chemotherapy dosing can lead to under- or over-dosing because BSA better accounts for the relationship between height and weight. This is critical for drugs with narrow therapeutic windows where dosing errors can significantly impact safety and efficacy.

Frequently Asked Questions

Which formula should I use for dosing?
The choice depends on your institution's protocols and the specific drug being administered. Many modern protocols favor Mosteller due to its improved accuracy in obese and pediatric patients. Always consult your institutional guidelines or the prescriber if unclear.
How often should body surface area be recalculated?
BSA should be recalculated whenever there is a significant change in patient weight (typically 5-10% change) or at minimum every cycle of treatment. Some institutions recalculate at each treatment visit.
Are these formulas accurate for all patient populations?
Both formulas are most accurate for adults of normal weight. Mosteller is more accurate for children and obese patients. For extremely underweight or obese patients, clinical judgment should be exercised, and the prescriber should be consulted if needed.
What is the difference between Du Bois and Mosteller for chemotherapy dosing?
In most cases, the difference between the two formulas is relatively small (typically within 10%). However, for dosing decisions, even small differences can be important for drugs with narrow therapeutic windows. Always use the formula specified in your institution's protocols.

Related Pharmacy Tools

swap_horiz

Unit Conversion

Convert between common pharmacy concentration units including percentage (% w/v, % w/w), mg/mL, mg/g, and more. Essential for compounding calculations.

monitor_weight

Ideal Body Weight

Calculate ideal body weight (IBW) and adjusted body weight (AdjBW) using the Devine formula. Used for drug dosing in clinical pharmacy practice.

medication

Capsule Reduction Planner

Plan an optimised dose tapering schedule using the fewest capsule strengths. Generates a step-by-step reduction table for compounding pharmacies.

science

Salt ↔ Base Conversion

Reference table and calculator for converting between salt forms and elemental/base equivalents. Covers calcium, magnesium, iron, fluoxetine, sildenafil, and more.

grid_on

Packing Competency

Assess capsule-filling uniformity across a 10×10 plate with guided weighing and heat map analysis to identify packing bias.

science

Capsule Packstat

Convert between capsule sizes and volumes, estimate packstats from powder density, and convert known packstats across capsule sizes for compounding formulation.

arrow_backBack to All Pharmacy Tools