Body Surface Area Calculator

Calculate your Body Surface Area (BSA) accurately using proven medical formulas. Essential for clinical dosing, medical assessments, and health monitoring.

cm
kg

BSA Categories

Small Adult: < 1.6 m²
Average Adult: 1.6 - 1.9 m²
Large Adult: > 1.9 m²

How It Works

The Body Surface Area (BSA) Calculator uses two industry-standard medical formulas—DuBois and Mosteller—to ensure precise, double-verified results for healthcare use.

1

Enter Measurements

Provide your height and weight in either metric (cm, kg) or imperial (ft, in, lbs) units.

2

Formula Calculation

The calculator computes BSA using both formulas DuBois and Mosteller

3

Get Results

View your total BSA in square meters, categorized by body size. Results also display both DuBois and Mosteller calculations for comparison.

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Understanding Body Surface Area

Learn about BSA calculation, its medical significance, and how it's used in clinical practice for accurate dosing and assessment.

What is Body Surface Area (BSA)?

Body Surface Area (BSA) represents the total outer surface of the human body, expressed in square meters (m²). In medicine, BSA is a critical parameter for determining safe and effective drug dosages—especially for chemotherapy, pediatric medications, and anesthesia.

Compared to body weight alone, BSA better reflects metabolic mass and correlates with vital functions such as cardiac output, kidney filtration, and basal metabolism. This makes BSA-based dosing one of the most reliable clinical standards worldwide. BSA is also essential in cardiology (cardiac index), nephrology (GFR estimation), and burn treatment calculations, providing consistent results across diverse medical fields.

DuBois Formula (1916)

This historically established formula remains the reference standard for chemotherapy dosing and adult medication scaling.

BSA = 0.007184 × Height^0.725 × Weight^0.425

Height in cm, weight in kg.

Mosteller Formula (1987)

Simpler yet accurate for bedside use and pediatric assessments. It is the most common equation used in modern hospital software systems.

BSA = √(Height × Weight / 3600)

Clinical Applications

These calculations guide dosage decisions that prevent under- or overdosing, ensuring patient safety and treatment efficacy.

Medication Dosing
  • Chemotherapy and oncology drug calculations
  • Pediatric and neonatal medication adjustments
  • Critical care infusions and anesthesia dosing
  • Hormone therapy and metabolic treatment planning
Medical Assessments
  • Cardiac index and stroke volume estimation
  • Renal and hepatic function scaling
  • Burn area evaluation in emergency medicine
  • Metabolic energy and heat exchange studies

Important Considerations

  • Professional Oversight: Always confirm BSA-based dosing with a licensed medical provider before applying clinically.
  • Population Variation: BSA estimates may vary with muscle mass, obesity, or dehydration.
  • Age-Specific Adjustments: Pediatric and geriatric patients require formula-based corrections.
  • Formula Comparison: DuBois may be preferred for oncology, while Mosteller suits rapid nursing assessments.
  • Clinical Calibration: Hospitals and pharmacies often integrate BSA calculators with EMR systems for precision dosing.

Frequently Asked Questions

BSA measures the total area of the human body and is expressed in square meters (m²). It’s primarily used in clinical medicine to calculate correct drug dosages.

Chemotherapy drugs have narrow therapeutic ranges. Dosing by BSA ensures consistency and reduces toxicity risk.

Both are valid. DuBois is considered the scientific reference, while Mosteller is easier for bedside use and equally reliable in most scenarios.

Yes. Both formulas can estimate pediatric BSA accurately when height and weight are measured correctly.

Typical adult BSA ranges from 1.6 to 1.9 m². Below 1.6 m² is small, and above 1.9 m² is large.

Medical staff multiply the prescribed drug dose (mg/m²) by the patient’s BSA to determine the correct dosage.

Yes, it’s suitable for education, research, or personal tracking—but clinical dosing should always be verified by a healthcare provider.

Absolutely. It’s widely used for learning dosage calculations and physiology.

There are approximate formulas that estimate BSA from weight alone, but results are less accurate than height-weight combined methods.

BSA helps calculate cardiac index, glomerular filtration rate (GFR), and drug clearance—all vital in clinical medicine.