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BSA Calculator - Body Surface Area

Ready to calculate
DuBois & DuBois Formula.
Mosteller & Boyd Equations.
Drug Dosing Reference Output.
100% Free.
No Data Stored.

How It Works

01Your Details

Enter gender, age, weight & patient type

02Select Units

Choose Metric (cm/kg) or Imperial (in/lb)

03Quick Calc

Get instant BSA using Mosteller model

04Formula Insights

Analyze variance across 6 clinical models

What is a BSA Calculator?

Bsa Calculator tool interface with upload form on toolsace.io
Body Surface Area is a critical measurement in medicine, used to calculate precise drug dosages, chemotherapy protocols, burn area assessments, and metabolic rate estimations. Unlike weight alone, BSA accounts for the relationship between height and weight in a way that more accurately reflects metabolic function for clinical purposes. Our BSA Calculator provides instant estimates using multiple validated formulas, making it a useful reference tool for healthcare providers, medical students, and researchers.

Several BSA formulas have been developed over the decades, each with slightly different mathematical approaches and validation populations. Our tool includes the Mosteller formula (the simplest and most widely used clinically), the DuBois & DuBois formula (the classic standard developed in 1916), the Haycock formula (often preferred for pediatric use), and others. Being able to compare results across formulas helps you understand the range of clinically accepted values for any given patient.

For clinical decision-making, always verify BSA calculations with your institution's approved protocols and consult appropriate medical references. This tool is intended as an educational and reference aid — not a replacement for clinical judgment. It's free, instant, and works on any device.

Pro Tip: For more relevant tools in the health category, try our BMI Tool.

How to Calculate Your BSA?

Enter Physical Data: Input your gender, age, height, and current weight.
Select Patient Profile: Choose between Adult, Child, or Infant settings for specialized precision.
Verify Units: Toggle between Metric (cm/kg) and Imperial (in/lbs) systems.
Analyze variance: Compare results from 6 clinical formulas (Mosteller, Du Bois, etc.) to ensure dosage accuracy.

How is Body Surface Area calculated?

There are several validated clinical formulas. The most common are:

Mosteller (Universal Standard)

BSA = √([H × W] / 3600)

Example: √(175cm × 70kg / 3600) = 1.84 m²

Du Bois (Classic Medical)

BSA = 0.007184 × W^0.425 × H^0.725

Example: 70kg and 175cm = 1.85 m²

Clinical Case Study

Jordan

Patient Context

Stature

1.80 Meters

Clinical mass

80.0 Kilograms

"Jordan is 1.80 meters tall and weighs 80 kg. To calculate the BSA using the Mosteller formula, we compute √((180 × 80) / 3600). The result is 2.00 m², which represents the total estimated skin surface area for clinical dosing."

Formula Variance: Why Multiple Models?

In the medical field, different formulas are favored based on the patient's demographic or the specific clinical application. No single formula is perfect for everyone.

Haycock (Pediatrics)

The Haycock formula is statistically superior for babies and small children, providing more accurate surface area estimates for tiny statures.

Fujimoto (Ethnic Specificity)

Developed specifically for Japanese populations, this formula accounts for skeletal and body composition variations common in Asian demographics.

BSA vs BMI: Key Differences

Feature BMI (Body Mass Index) BSA (Body Surface Area)
Measures Weight-to-height ratio Total skin surface area
Primary Use Health screening / Obesity Clinical dosing / Diagnostics
Units kg/m² (Ratio) m² (Area)

Applications of Surface Area Metrics

1
Chemotherapy Dosing: Calculating precise medication volumes to maximize efficacy while minimizing toxicity.
2
Kidney Function: Normalizing Glomerular Filtration Rate (GFR) to assess renal health objectively.
3
Cardiovascular Monitoring: Calculating the Cardiac Index to evaluate heart performance relative to body size.
4
Burn Assessment: Estimating skin surface area for fluid resuscitation and treatment planning.
5
Pediatric Medicine: Sizing drug dosages for children where weight-based dosing may be inaccurate.

Technical Reference

Key Takeaways

Your health journey starts with understanding your baseline. Use the ToolsACE BMI Calculator to get accurate, actionable data about your body mass index today. By keeping your BMI within the healthy range, you significantly reduce the risk of chronic lifestyle diseases like heart disease and diabetes. Use these results as a compass to guide your nutrition, fitness, and overall wellness goals.

Frequently Asked Questions

What is the ?
Body Surface Area is a critical measurement in medicine, used to calculate precise drug dosages, chemotherapy protocols, burn area assessments, and metabolic rate estimations. Unlike weight alone, BSA accounts for the relationship between height and weight in a way that more accurately reflects metabolic function for clinical purposes. Our BSA Calculator provides instant estimates using multiple validated formulas, making it a useful reference tool for healthcare providers, medical students, and researchers.

Several BSA formulas have been developed over the decades, each with slightly different mathematical approaches and validation populations. Our tool includes the Mosteller formula (the simplest and most widely used clinically), the DuBois & DuBois formula (the classic standard developed in 1916), the Haycock formula (often preferred for pediatric use), and others. Being able to compare results across formulas helps you understand the range of clinically accepted values for any given patient.

For clinical decision-making, always verify BSA calculations with your institution's approved protocols and consult appropriate medical references. This tool is intended as an educational and reference aid — not a replacement for clinical judgment. It's free, instant, and works on any device.

Pro Tip: For more relevant tools in the health category, try our BMI Tool.

Which BSA formula does the calculator use?
It offers multiple formulas including Mosteller, DuBois & DuBois, Haycock, and Gehan-George, so you can compare results.
Which formula is most accurate?
The Mosteller formula is widely used in clinical practice for its simplicity and reliability. Haycock is often preferred for pediatric patients.
Can this be used for pediatric patients?
Yes — the Haycock formula is specifically validated for children and is available in the calculator.
What units are supported?
Both metric (cm/kg) and imperial (inches/lbs) units are supported.
Is this tool for medical professionals only?
No — it's also useful for students, researchers, and anyone learning about clinical measurements.
Should clinicians rely solely on this tool?
No — always verify calculations using your institution's approved clinical tools and protocols.
Is it free?
Yes, completely free.
Does it work on mobile?
Yes, fully mobile-friendly.
What's the typical BSA for an adult?
The average adult BSA is approximately 1.7–1.9 m², though this varies significantly with height and weight.

Author Spotlight

The ToolsACE Team - ToolsACE.io Team

The ToolsACE Team

Our health tools team computes Body Surface Area using the DuBois & DuBois formula (BSA = 0.007184 × height^0.725 × weight^0.425), plus the simpler Mosteller formula (BSA = √(height × weight / 3600)) — commonly used in clinical oncology for chemotherapy dose calculation.

DuBois & Mosteller BSA FormulasClinical Drug Dosing ReferenceSoftware Engineering Team

Medical Disclaimer

The results provided by this tool are for informational purposes only and do not constitute medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.