Surface Area Body Calculator

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Body Surface Area (BSA) Calculator
Mosteller (Standard)Du Bois and Du BoisHaycockBoydGehan and George
Metric (kg, cm)Imperial (lb, in)
Result:

Body Surface Area = m²
function toggleUnits(){var u=document.getElementById('units').value;if(u==='metric'){document.getElementById('weightLabel').innerHTML='Weight (kg):';document.getElementById('heightLabel').innerHTML='Height (cm):';}else{document.getElementById('weightLabel').innerHTML='Weight (lbs):';document.getElementById('heightLabel').innerHTML='Height (in):';}}function calculateBSA(){var w=parseFloat(document.getElementById('weight').value);var h=parseFloat(document.getElementById('height').value);var f=document.getElementById('formula').value;var u=document.getElementById('units').value;var showSteps=document.getElementById('steps').checked;if(isNaN(w)||isNaN(h)){alert('Please enter valid numeric values for height and weight.');return;}var wKg=w;var hCm=h;if(u==='imperial'){wKg=w*0.45359237;hCm=h*2.54;}var bsa=0;var details="";if(f==='mosteller'){bsa=Math.sqrt((hCm*wKg)/3600);details="Formula: sqrt([Height(cm) x Weight(kg)] / 3600)
Steps: sqrt(("+hCm.toFixed(2)+" x "+wKg.toFixed(2)+") / 3600)";}else if(f==='dubois'){bsa=0.007184*Math.pow(hCm,0.725)*Math.pow(wKg,0.425);details="Formula: 0.007184 x H^0.725 x W^0.425
Steps: 0.007184 x "+hCm.toFixed(2)+"^0.725 x "+wKg.toFixed(2)+"^0.425″;}else if(f==='haycock'){bsa=0.024265*Math.pow(hCm,0.3964)*Math.pow(wKg,0.5378);details="Formula: 0.024265 x H^0.3964 x W^0.5378″;}else if(f==='gehan'){bsa=0.0235*Math.pow(hCm,0.42246)*Math.pow(wKg,0.51456);details="Formula: 0.0235 x H^0.42246 x W^0.51456″;}else if(f==='boyd'){var wGm=wKg*1000;var exponent=0.7285-(0.0188*(Math.log10(wGm)));bsa=0.0003207*Math.pow(hCm,0.3)*Math.pow(wGm,exponent);details="Formula: 0.0003207 x H^0.3 x Weight(grams)^(0.7285 – 0.0188 x log10(grams))";}document.getElementById('resultValue').innerHTML=bsa.toFixed(4);if(showSteps){document.getElementById('stepDetails').innerHTML=details;document.getElementById('stepDetails').style.display='block';}else{document.getElementById('stepDetails').style.display='none';}document.getElementById('answer').style.display='block';}

How to Use the Surface Area Body Calculator

The surface area body calculator is an essential tool for medical professionals and health enthusiasts alike. It measures the total surface area of the human body (BSA), which is often considered a more accurate indicator of metabolic mass than body weight alone. This metric is frequently used in clinical settings to calculate dosages for chemotherapy, steroids, and other high-risk medications.

To use this calculator, simply follow these steps:

Select Formula
Choose from popular mathematical models like Mosteller, Du Bois, or Haycock depending on your clinical requirement.
Choose Units
Toggle between Metric (kilograms and centimeters) or Imperial (pounds and inches) systems.
Enter Height & Weight
Input your current measurements accurately to ensure the most precise BSA result.

How It Works: The Formulas Behind BSA

Body surface area is not easily measured directly. Instead, mathematicians and researchers have developed several regression formulas. Our surface area body calculator utilizes the five most recognized formulas in medical science:

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

  • Mosteller: The most widely used due to its simplicity and accuracy across different body types.
  • Du Bois: One of the oldest formulas (1916), specifically reliable for individuals with average body compositions.
  • Haycock: Preferred for pediatric patients (infants and children) because it accounts for smaller physical statures.
  • Boyd: A more complex formula often used in research settings involving nutritional assessments.

Calculation Example

Example: Let's calculate the body surface area for an adult male weighing 80 kg and standing 180 cm tall using the Mosteller method.

Step-by-step solution:

  1. Weight = 80 kg
  2. 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 = 2.00 m²

Common Questions about BSA

Why is BSA better than BMI?

While Body Mass Index (BMI) tells us about weight relative to height, BSA tells us about the metabolic surface. In pharmacology, many drug clearances are better correlated with BSA than with total body weight because lean body mass is more metabolically active.

What is the average BSA for adults?

The average body surface area for an adult man is generally cited as 1.9 m², while for an adult woman, it is approximately 1.6 m². However, these values vary significantly based on age, gender, and fitness level.

Which formula is most accurate?

The Mosteller formula is currently the standard in most clinical practices because it is easy to remember and yields results very similar to the more complex Haycock or Du Bois equations. For children, medical providers usually lean toward the Haycock formula.

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