Body Surface Area (BSA) Calculator – Accurate & Free Online Tool

The Body Surface Area (BSA) Calculator helps you estimate the total surface area of your body based on your height and weight. BSA is widely used in medical practice to calculate drug dosages, chemotherapy levels, IV fluids, burn assessment, and organ function measurements.

Use our free BSA calculator to instantly calculate your body surface area using clinically accepted formulas.

What Is Body Surface Area (BSA)?

Body Surface Area (BSA) is the total area of the human body measured in square meters (m²).

Unlike BMI (Body Mass Index), BSA is commonly used in:

• Medication dosage calculations

• Chemotherapy dosing

• Pediatric medicine

• Burn treatment assessment

• Cardiac index calculations

• Kidney function measurement (GFR adjustment)

Doctors prefer BSA in many cases because it provides a more accurate metabolic mass estimate than body weight alone.

BSA Formula (Most Common Method)

The most widely used formula is the Du Bois Formula (1916):

BSA=0.007184×Height0.725×Weight0.425BSA = 0.007184 × Height^{0.725} × Weight^{0.425}BSA=0.007184×Height0.725×Weight0.425

Where:

• Height = in centimeters

• Weight = in kilograms

• Result = in square meters (m²)

Other Popular BSA Formulas

1️⃣ Mosteller Formula (Most Common in Hospitals)

BSA=Height(cm)×Weight(kg)3600BSA = \sqrt{\frac{Height (cm) × Weight (kg)}{3600}}BSA=3600Height(cm)×Weight(kg)​​

✔ Simple
✔ Very accurate
✔ Widely used in clinical settings

2️⃣ Haycock Formula

BSA=0.024265×Height0.3964×Weight0.5378BSA = 0.024265 × Height^{0.3964} × Weight^{0.5378}BSA=0.024265×Height0.3964×Weight0.5378

Often used for children and infants.

3️⃣ Gehan & George Formula

Another validated medical formula used in research studies.

Why Is BSA Important?

BSA plays a critical role in medicine because:

💊 1. Drug Dosage Calculation

Certain drugs (especially chemotherapy) are prescribed in mg/m² instead of mg/kg.

🔥 2. Burn Treatment

Burn severity is measured as % of BSA affected.

❤️ 3. Cardiac Index

Heart function is adjusted according to BSA.

🩺 4. Kidney Function (GFR)

Glomerular filtration rate is normalized to 1.73 m² BSA.

Example Calculation

Let’s calculate BSA using the Mosteller formula:

• Height: 170 cm

• Weight: 70 kg

BSA=170×703600BSA = \sqrt{\frac{170 × 70}{3600}}BSA=3600170×70​​ BSA≈1.8m2BSA ≈ 1.8 m²BSA≈1.8m2

That means the person’s total body surface area is approximately 1.8 square meters.

Normal BSA Values

BSA vs BMI – What’s the Difference?

They serve different medical purposes.

Who Should Use a BSA Calculator?

• Doctors & medical professionals

• Nursing students

• Pharmacy students

• Oncology patients

• Burn unit staff

• Medical researchers

Is BSA Accurate?

BSA formulas are estimates, but they are clinically validated and widely accepted worldwide.

The Mosteller formula is considered highly accurate and simple for daily use.

Frequently Asked Questions (FAQs)

What is normal BSA?

Most adults fall between 1.6 m² and 2.0 m².

Which BSA formula is best?

The Mosteller formula is the most commonly used in hospitals.

Is BSA better than BMI?

For medical dosing and treatment, yes.
For weight classification, BMI is more appropriate.

Can I calculate BSA in pounds and inches?

Yes, but height must be converted to cm and weight to kg first.

Use Our Free Body Surface Area Calculator

Our tool:

✔ Instant calculation
✔ Accurate medical formulas
✔ Mobile friendly
✔ No registration required
✔ 100% free

Simply enter your height and weight, and get your BSA result immediately.

Related Health Calculators

You may also like:

• BMI Calculator

• BMR Calculator

• TDEE Calculator

• Body Fat Calculator

• GFR Calculator

Final Thoughts

Body Surface Area (BSA) is an essential measurement in modern medicine. Whether you’re a healthcare professional or a student, using a reliable BSA calculator ensures accurate dosage and medical assessment.

Try our free Body Surface Area Calculator today and get instant results.