Bsa Calculator

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BSA Calculator (Body Surface Area)
Mosteller Formula (Recommended)Du Bois FormulaHaycock FormulaGehan & George FormulaBoyd Formula
kglbs
cmin
Result:
0.00 m²
Enter height and weight to calculate Body Surface Area.
© Calculator Soup Style BSA Tool
function calculateBSA(){var weightVal=parseFloat(document.getElementById('weight_input').value);var heightVal=parseFloat(document.getElementById('height_input').value);var weightUnit=document.getElementById('weight_unit').value;var heightUnit=document.getElementById('height_unit').value;var formula=document.getElementById('formula_type').value;if(isNaN(weightVal)||isNaN(heightVal)){alert('Please enter valid numeric values for height and weight.');return;}var w=weightVal;if(weightUnit==='lb'){w=weightVal*0.453592;}var h=heightVal;if(heightUnit==='in'){h=heightVal*2.54;}var bsa=0;var formulaName=";if(formula==='mosteller'){bsa=Math.sqrt((h*w)/3600);formulaName='Mosteller';}else if(formula==='dubois'){bsa=0.007184*Math.pow(w,0.425)*Math.pow(h,0.725);formulaName='Du Bois';}else if(formula==='haycock'){bsa=0.024265*Math.pow(w,0.5378)*Math.pow(h,0.3964);formulaName='Haycock';}else if(formula==='gehan'){bsa=0.0235*Math.pow(w,0.51456)*Math.pow(h,0.42246);formulaName='Gehan & George';}else if(formula==='boyd'){var grams=w*1000;var exponent=0.7285-(0.0188*Math.log10(grams));bsa=0.0003207*Math.pow(h,0.3)*Math.pow(grams,exponent);formulaName='Boyd';}document.getElementById('bsaValue').innerHTML=bsa.toFixed(2)+' m²';var detailsText='Calculated using the '+formulaName+' formula.';if(document.getElementById('steps').checked){detailsText+='

Reference Average BSA:
Adult Men: 1.9 m² | Adult Women: 1.6 m²';}document.getElementById('details').innerHTML=detailsText;}

BSA Calculator Use

The Body Surface Area (BSA) calculator is a vital tool used by medical professionals to determine the total surface area of a human body. Unlike Body Mass Index (BMI), which measures body fat based on weight and height, BSA provides a more accurate metric for physiological processes, such as metabolic rate and cardiac output. This bsa calculator allows you to switch between various established clinical formulas and supports both Metric and Imperial units.

BSA is most commonly used in clinical settings to calculate precise dosages for chemotherapy, corticosteroids, and other medications with narrow therapeutic windows where dosing must be exact to avoid toxicity.

Weight
Enter the patient's current weight in kilograms (kg) or pounds (lbs).
Height
Enter the patient's height in centimeters (cm) or inches (in).
Formula Selection
Choose from Mosteller, Du Bois, Haycock, Boyd, or Gehan & George depending on your clinical requirement.

How It Works: BSA Formulas

There is no single "perfect" formula for BSA, but the Mosteller formula is the most widely adopted due to its simplicity and accuracy across different body types. Our bsa calculator uses the following primary equations:

Mosteller Formula:

BSA (m²) = √([Height(cm) × Weight(kg)] / 3600)

Du Bois Formula:

BSA (m²) = 0.007184 × Weight(kg)⁰.⁴²⁵ × Height(cm)⁰.⁷²⁵

  • Mosteller: Released in 1987, it simplified the calculation significantly and is now the standard in most clinical practices.
  • Du Bois: One of the oldest formulas (1916), still frequently cited in medical research.
  • Haycock: Often preferred for pediatric patients (infants and children).
  • Boyd: Considered highly accurate for patients with low body fat or extreme variations in size.

Calculation Example

Example: Calculating the BSA for an adult male weighing 80 kg with a height of 180 cm using the Mosteller formula.

Step-by-step solution:

  1. Identify Weight: 80 kg
  2. Identify Height: 180 cm
  3. Multiply Height by Weight: 180 × 80 = 14,400
  4. Divide by 3,600: 14,400 / 3,600 = 4
  5. Take the Square Root: √4 = 2.00
  6. Final BSA Result: 2.00 m²

Common Questions

Why is BSA used instead of Weight for medication?

BSA correlates more closely with physiological functions like glomerular filtration rate (kidneys) and cardiac output than total body weight. This is particularly important for drugs that distribute primarily in the extracellular fluid or require precise clearance monitoring.

What is a normal BSA for an adult?

The average Body Surface Area for a man is approximately 1.9 m², while for a woman it is roughly 1.6 m². Neonates typically have a BSA around 0.25 m², while children usually range between 0.5 and 1.3 m² depending on age and growth.

Which formula is the most accurate?

While studies suggest slight variations in accuracy at extreme weights (morbid obesity or severe malnutrition), the Mosteller formula provided by our bsa calculator is widely considered accurate enough for general clinical use and is the easiest to verify manually.

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