🩺 Body Surface Area (Mosteller) Calculator
Free Medical Calculator for Healthcare Professionals & Students
Your Body Surface Area
BSA = √[(Height × Weight) / 3600]
Introduction
The Body Surface Area (BSA) Calculator uses the Mosteller formula to estimate the total surface area of the human body based on height and weight. BSA is widely used by healthcare professionals to calculate medication dosages, chemotherapy doses, intravenous fluid requirements, cardiac index, renal function assessments, and other clinical measurements.
The Mosteller equation is one of the simplest and most widely accepted methods because it is accurate, easy to calculate, and commonly used in hospitals, medical schools, and clinical practice worldwide.
Simply enter your height (cm) and weight (kg) to calculate your Body Surface Area instantly.
What Is Body Surface Area (BSA)?
Body Surface Area (BSA) is the total external surface area of the human body expressed in square meters (m²).
Unlike Body Mass Index (BMI), which estimates body fat based on height and weight, BSA estimates body size. This makes it particularly useful for determining medication dosages and physiological measurements that depend on body size rather than body weight alone.
Mosteller Formula
BSA (m²) = √[(Height (cm) × Weight (kg)) ÷ 3600]
The Mosteller formula was introduced in 1987 and has become one of the most commonly used equations because it provides reliable results while remaining easy to calculate.
How to Use the Calculator
- Enter your height in centimeters.
- Enter your weight in kilograms.
- Click Calculate.
- View your Body Surface Area in square meters.
- Read the clinical interpretation below the result.
Example Calculation
Height: 170 cm
Weight: 65 kg
Calculation:
√[(170 × 65) ÷ 3600]
BSA = 1.75 m²
Why Is Body Surface Area Important?
Healthcare professionals use BSA because many physiological functions correlate better with body surface area than body weight alone.
Common clinical uses include:
- Chemotherapy drug dosing
- Pediatric medication calculations
- Cardiac index calculations
- Burn assessment
- Kidney function assessment
- Organ transplantation
- Critical care medicine
- Clinical nutrition
- Fluid therapy
- Pharmacokinetic calculations
Advantages of the Mosteller Formula
- Easy to calculate
- Clinically validated
- Widely accepted worldwide
- Suitable for adults and children
- Frequently used in hospitals
- Recommended in many medical references
Normal Body Surface Area
Typical BSA values are:
| Person | Typical BSA |
|---|---|
| Adult Female | 1.5–1.8 m² |
| Adult Male | 1.7–2.2 m² |
| Children | Depends on age and growth |
These values are approximate and vary depending on body size.
Difference Between BMI and BSA
| BMI | BSA |
|---|---|
| Estimates body fat | Estimates body size |
| Used for obesity assessment | Used for drug dosing |
| Expressed as kg/m² | Expressed as m² |
| Mainly for health screening | Mainly for clinical calculations |
Clinical Applications
Body Surface Area is commonly used in:
- Oncology
- Nephrology
- Pediatrics
- Cardiology
- Intensive Care Units
- Emergency Medicine
- Surgery
- Clinical Pharmacology
- Organ Transplantation
Frequently Asked Questions
Which formula is most commonly used for BSA?
The Mosteller formula is among the most widely used because it is simple, accurate, and practical.
Is the BSA calculator accurate?
Yes. The calculator provides accurate results when correct height and weight values are entered.
Can children use this calculator?
Yes. The Mosteller formula is commonly used for both adults and children.
What unit is BSA measured in?
Body Surface Area is measured in square meters (m²).
Why do doctors use BSA instead of BMI?
Many medications, particularly chemotherapy drugs, are dosed according to body surface area because it more closely reflects physiological processes than body weight alone.
Medical Disclaimer
This calculator is provided for educational and informational purposes only. It is not intended to replace professional medical advice, diagnosis, or treatment. Clinical decisions should always be made by qualified healthcare professionals.