.amputee-bmi-container {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen-Sans, Ubuntu, Cantarell, "Helvetica Neue", sans-serif;
max-width: 800px;
margin: 20px auto;
padding: 25px;
border: 1px solid #e1e1e1;
border-radius: 12px;
background-color: #fdfdfd;
box-shadow: 0 4px 15px rgba(0,0,0,0.05);
color: #333;
}
.amputee-bmi-container h2 {
color: #2c3e50;
text-align: center;
margin-bottom: 25px;
}
.input-group {
margin-bottom: 20px;
}
.input-group label {
display: block;
font-weight: 600;
margin-bottom: 8px;
color: #444;
}
.input-group input, .input-group select {
width: 100%;
padding: 12px;
border: 1px solid #ccc;
border-radius: 6px;
font-size: 16px;
box-sizing: border-box;
}
.amputation-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 10px;
margin-bottom: 20px;
background: #f1f4f7;
padding: 15px;
border-radius: 8px;
}
.checkbox-item {
display: flex;
align-items: center;
font-size: 14px;
}
.checkbox-item input {
width: auto;
margin-right: 10px;
}
.calc-btn {
width: 100%;
background-color: #27ae60;
color: white;
padding: 15px;
border: none;
border-radius: 6px;
font-size: 18px;
font-weight: bold;
cursor: pointer;
transition: background 0.3s;
}
.calc-btn:hover {
background-color: #219150;
}
#bmi-result {
margin-top: 25px;
padding: 20px;
border-radius: 8px;
text-align: center;
display: none;
}
.result-value {
font-size: 32px;
font-weight: bold;
display: block;
}
.result-category {
font-size: 18px;
font-weight: 600;
margin-top: 5px;
}
.info-section {
margin-top: 40px;
line-height: 1.6;
color: #555;
}
.info-section h3 {
color: #2c3e50;
border-bottom: 2px solid #27ae60;
padding-bottom: 8px;
margin-top: 30px;
}
.percentage-table {
width: 100%;
border-collapse: collapse;
margin: 15px 0;
}
.percentage-table th, .percentage-table td {
border: 1px solid #ddd;
padding: 10px;
text-align: left;
}
.percentage-table th {
background-color: #f8f9fa;
}
BMI for Amputees Calculator
Current Weight (kg)
Height (cm)
Select Amputated Limbs:
Hand (0.7%)
Forearm (1.6%)
Upper Arm (2.7%)
Entire Arm (5.0%)
Foot (1.5%)
Lower Leg (BKA) (5.9%)
Upper Leg (AKA) (10.1%)
Entire Leg (16.0%)
Calculate Corrected BMI
Why Amputees Need a Corrected BMI
Standard Body Mass Index (BMI) calculations assume a complete human anatomy. When a limb is missing, the individual's total body weight decreases, but their height remains a primary factor in the health calculation. This often leads to an artificially low BMI reading that doesn't accurately reflect the individual's body fat percentage or metabolic health.
To find a realistic BMI, we must estimate what the user's "theoretical" weight would be if the limb were still present. This is done using the Amputee BMI Formula developed by researchers (notably Osterkamp, 1995).
The Amputee BMI Formula
The calculation involves two steps:
Estimated Total Body Weight: Current Weight / (1 – Proportion of Weight for Missing Limb)Corrected BMI: Estimated Total Body Weight / (Height in meters)²
Standard Limb Weight Percentages
Limb Description
% of Total Body Weight
Hand 0.7% Forearm 1.6% Upper Arm 2.7% Entire Arm 5.0% Foot 1.5% Lower Leg (Below Knee) 5.9% Upper Leg (Above Knee) 10.1% Entire Leg 16.0%
BMI Categories
Underweight: BMI less than 18.5Normal weight: BMI 18.5 to 24.9Overweight: BMI 25 to 29.9Obesity: BMI 30 or greater
Example Calculation
If an individual weighs 70kg, is 175cm tall, and has an entire leg amputation (16%):
Adjusted Weight = 70 / (1 – 0.16) = 70 / 0.84 = 83.33 kg
Corrected BMI = 83.33 / (1.75 * 1.75) = 27.2
Standard BMI would have been 22.8 (Normal), but the Corrected BMI is 27.2 (Overweight).
function calculateAmputeeBMI() {
var weight = parseFloat(document.getElementById('currentWeight').value);
var heightCm = parseFloat(document.getElementById('heightCm').value);
var resultDiv = document.getElementById('bmi-result');
var bmiVal = document.getElementById('bmi-val');
var bmiCat = document.getElementById('bmi-cat');
var weightInfo = document.getElementById('weight-info');
if (isNaN(weight) || isNaN(heightCm) || weight <= 0 || heightCm <= 0) {
alert("Please enter valid positive numbers for weight and height.");
return;
}
// Calculate total missing percentage
var checkboxes = document.getElementsByClassName('limb-check');
var totalMissingProp = 0;
for (var i = 0; i 100% (physically impossible but prevents div by zero)
if (totalMissingProp >= 1) {
alert("The selected amputations exceed total body mass calculations.");
return;
}
// Step 1: Estimated Body Weight (EBW)
var ebw = weight / (1 – totalMissingProp);
// Step 2: BMI Calculation (Metric)
var heightM = heightCm / 100;
var bmi = ebw / (heightM * heightM);
// Display results
resultDiv.style.display = 'block';
bmiVal.innerHTML = bmi.toFixed(1);
weightInfo.innerHTML = "Estimated weight if limbs were present: " + ebw.toFixed(1) + " kg";
// Categories and Styling
var category = "";
var bgColor = "";
var textColor = "#fff";
if (bmi < 18.5) {
category = "Underweight";
bgColor = "#3498db";
} else if (bmi < 25) {
category = "Normal Weight";
bgColor = "#27ae60";
} else if (bmi < 30) {
category = "Overweight";
bgColor = "#f1c40f";
textColor = "#333";
} else {
category = "Obese";
bgColor = "#e74c3c";
}
bmiCat.innerHTML = category;
resultDiv.style.backgroundColor = bgColor;
resultDiv.style.color = textColor;
}