BSA & Chemotherapy Dosing Calculator

Last updated: 2026-09-09

BSA & Chemotherapy Dosing Calculator — Calculate BSA using Mosteller or Du Bois formulas and convert mg/m² chemotherapy doses to actual mg per administration.

Inputs

Result

Enter values and press Calculate

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Common Examples — Click to Fill

	Height (cm)	Weight (kg)	Formula Type	Dose per m² (mg/m²)
Adult chemo, standard	170	70	Mosteller	100
Pediatric leukemia maintenance	120	25	Dubois	75
Large adult, high dose	190	110	Mosteller	150
Elderly small frame, low dose	160	55	Dubois	50

How to Use This Calculator

This calculator helps oncology professionals and patients determine body surface area (BSA) and convert chemotherapy dose from per-square-meter to actual milligrams. Start by entering the patient's height in centimeters and weight in kilograms. Then choose the BSA formula you want to use: Mosteller (recommended for adults) or Du Bois (an older formula often used in research). If you have a prescribed dose in mg/m², enter it in the optional field. Click 'Calculate' to get the BSA and the total dose for a single administration.

Formula and Methodology

Mosteller formula: BSA (m²) = √(height (cm) × weight (kg) / 3600). It is simple and widely accepted. Du Bois formula: BSA = 0.007184 × height (cm)^0.725 × weight (kg)^0.425. This formula was derived from a limited population and may slightly differ, especially for extremes of height and weight. For dosing, BSA is used to account for the patient's metabolic mass, aiming to provide a more personalized dose than weight-based dosing.

Practical Examples

Consider a patient with height 170 cm and weight 70 kg. Using Mosteller: BSA = √(170×70/3600) = √3.3056 ≈ 1.82 m². If the prescribed dose is 100 mg/m², total dose = 1.82 × 100 = 182 mg. Using Du Bois: BSA = 0.007184 × 170^0.725 × 70^0.425 ≈ 1.85 m² (slightly different). Total dose would be 185 mg. This difference may matter for highly toxic drugs, so accuracy is critical.

Tips and Best Practices

Always use the exact height and weight taken on the same day. Use a calibrated scale and stadiometer. For obese patients, some protocols use adjusted body weight for dosing; consult guidelines. Double-check all calculations with a second professional or pharmacist. Round BSA to two decimal places and dose to one decimal place as per institutional policy. Be aware of drug-specific dose adjustments for organ dysfunction. This calculator is for educational purposes; clinical decisions must be made by qualified healthcare providers.

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FAQ

What does BSA stand for and why is it important in chemotherapy dosing?

BSA stands for Body Surface Area, a measurement of the total surface area of your body calculated from your height and weight. It is important in chemotherapy dosing because many chemotherapy drugs are dosed based on BSA rather than body weight alone, as BSA better correlates with blood volume and organ metabolism, helping to ensure therapeutic efficacy while minimizing toxicity.

Which BSA formulas does this calculator support?

Our calculator supports the three most commonly used clinical formulas: Mosteller, Du Bois, and Haycock. Each formula uses height and weight differently, so you can compare results to see how BSA variations might affect your prescribed dose, though Mosteller is the most widely used in modern oncology practice.

How do I calculate the chemotherapy dose with this tool?

First, enter your height (in cm or inches) and weight (in kg or lbs), then select a BSA formula. After the BSA is calculated, input the drug-specific dose per square meter (mg/m²) as provided by your oncologist or protocol, and the tool will multiply that by your BSA to output the total dose in mg or mg/kg, depending on the drug's standard dosing unit.

Is this calculator a substitute for professional medical advice?

No, this calculator is for educational and reference purposes only, and it must not be used to self-administer or adjust chemotherapy without direct supervision from a licensed oncologist. Actual dosing requires clinical judgment, organ function tests (e.g., liver and kidney), drug interactions, and the specific protocol’s guidelines, so always confirm your final dose with your healthcare team.