Standard Body Mass Index (BMI) calculations are inaccurate for individuals with limb loss because they do not account for the weight of the missing limb. This results in a misleadingly low BMI score that may mask obesity or health risks.
This calculator uses standard medical formulas to determine your Adjusted BMI by estimating your body weight as if the missing limb(s) were present.
Pounds (lbs)
0
1
2
0
1
2
0
1
2
0
1
2
0
1
2
0
1
2
0
1
2
0
1
2
Note: Select "Below Knee" OR "Foot", not both for the same leg.
Your Estimated Body Weight (If limbs were present): –
Adjusted BMI: –
Standard BMI (Without Correction): –
Understanding Amputee BMI Corrections
Body Mass Index (BMI) is a screening tool used to categorize weight status. For amputees, the loss of body mass from a limb reduces the total body weight used in the standard formula (Weight / Height²). Without correction, an amputee might appear to be in a "normal" or "underweight" range despite having excess adipose tissue relative to their remaining body mass.
The Correction Formula
To calculate an accurate BMI for an amputee, we first determine the Estimated Ideal Body Weight. This is done by dividing the current weight by the fraction of the body surface area remaining.
Formula: Estimated Weight = Current Weight / (1 – % of Limb Loss)
Limb Weight Percentages
This calculator utilizes standard reference values for the percentage of total body weight represented by different limbs. These are approximations generally accepted in clinical nutrition and prosthetics:
Body Part
Percentage of Total Body Weight
Hand
0.7%
Forearm and Hand (Below Elbow)
2.3%
Entire Arm (Above Elbow)
5.0%
Foot
1.5%
Lower Leg and Foot (Below Knee)
5.9%
Entire Leg (Above Knee)
16.0%
Interpreting Your Results
After adjusting the weight, the BMI is calculated using the standard WHO classifications:
Underweight: BMI less than 18.5
Normal weight: BMI 18.5 – 24.9
Overweight: BMI 25 – 29.9
Obesity: BMI 30 or greater
Medical Disclaimer: This calculator provides an estimation for informational purposes only. Individual body composition variations, muscle mass, and bone density can affect actual health status. Please consult with a physician, prosthetist, or dietitian for a comprehensive health assessment.
var currentUnit = 'imperial';
function toggleUnits() {
var radios = document.getElementsByName('units');
for (var i = 0; i = 100) {
alert("Percentage of lost limbs cannot equal or exceed 100%. Please check your selection.");
return;
}
// 4. Calculate Adjusted Weight
// Formula: CurrentWeight / (1 – %Lost/100)
var fractionRemaining = 1 – (totalPercentLost / 100);
var adjustedWeightKg = weightKg / fractionRemaining;
// 5. Calculate BMI
var adjustedBMI = adjustedWeightKg / (heightMeters * heightMeters);
var standardBMI = weightKg / (heightMeters * heightMeters);
// 6. Display Results
var resultArea = document.getElementById('results-area');
resultArea.style.display = 'block';
// Display Adjusted Weight
if (currentUnit === 'imperial') {
var adjWeightLbs = adjustedWeightKg * 2.20462;
document.getElementById('res-adj-weight').innerText = adjWeightLbs.toFixed(1) + " lbs";
} else {
document.getElementById('res-adj-weight').innerText = adjustedWeightKg.toFixed(1) + " kg";
}
// Display BMI
document.getElementById('res-bmi').innerText = adjustedBMI.toFixed(1);
document.getElementById('res-std-bmi').innerText = standardBMI.toFixed(1);
// Category
var categorySpan = document.getElementById('res-category');
var categoryText = "";
var badgeClass = "";
if (adjustedBMI = 18.5 && adjustedBMI = 25 && adjustedBMI < 30) {
categoryText = "Overweight";
badgeClass = "bmi-badge bmi-over";
} else {
categoryText = "Obese";
badgeClass = "bmi-badge bmi-obese";
}
categorySpan.className = badgeClass;
categorySpan.innerText = categoryText;
}