Calculate your Body Mass Index quickly and accurately using metric or imperial units.
Metric (kg / cm)
Imperial (lb / ft / in)
Your BMI is:
Understanding Body Mass Index (BMI)
The BMI Calculator Net is a specialized tool designed to estimate body fat based on your height and weight. It is widely used by healthcare professionals to categorize individuals into weight groups that may lead to health problems.
How BMI is Calculated
The Body Mass Index is calculated using two main formulas depending on the unit system used:
To better understand how your height and weight correlate to your BMI result, consider these realistic examples:
Example 1: A person weighing 70kg (154 lbs) with a height of 175cm (5'9″) has a BMI of 22.9 (Normal Weight).
Example 2: A person weighing 90kg (198 lbs) with a height of 180cm (5'11") has a BMI of 27.8 (Overweight).
Example 3: A person weighing 50kg (110 lbs) with a height of 165cm (5'5″) has a BMI of 18.4 (Underweight).
Limitations of BMI
While the BMI Calculator Net provides a useful starting point, it is not a diagnostic tool. BMI does not account for muscle mass, bone density, or overall body composition. For example, athletes with high muscle mass may have a high BMI without having high body fat.
function toggleUnits() {
var unit = document.getElementById("bmi-unit").value;
var metricBox = document.getElementById("metric-inputs");
var imperialBox = document.getElementById("imperial-inputs");
if (unit === "metric") {
metricBox.style.display = "block";
imperialBox.style.display = "none";
} else {
metricBox.style.display = "none";
imperialBox.style.display = "block";
}
document.getElementById("bmi-result-box").style.display = "none";
}
function calculateBMI() {
var unit = document.getElementById("bmi-unit").value;
var bmi = 0;
var weight = 0;
var heightInMeters = 0;
if (unit === "metric") {
weight = parseFloat(document.getElementById("weight-metric").value);
var heightCm = parseFloat(document.getElementById("height-metric").value);
if (!weight || !heightCm || weight <= 0 || heightCm <= 0) {
alert("Please enter valid positive numbers for weight and height.");
return;
}
heightInMeters = heightCm / 100;
bmi = weight / (heightInMeters * heightInMeters);
} else {
weight = parseFloat(document.getElementById("weight-imperial").value);
var feet = parseFloat(document.getElementById("height-ft").value) || 0;
var inches = parseFloat(document.getElementById("height-in").value) || 0;
if (!weight || weight <= 0 || (feet <= 0 && inches <= 0)) {
alert("Please enter valid positive numbers for weight and height.");
return;
}
var totalInches = (feet * 12) + inches;
bmi = (weight / (totalInches * totalInches)) * 703;
}
displayResult(bmi);
}
function displayResult(bmi) {
var resultBox = document.getElementById("bmi-result-box");
var bmiValue = document.getElementById("bmi-value");
var bmiCategory = document.getElementById("bmi-category");
var bmiRangeInfo = document.getElementById("bmi-range-info");
resultBox.style.display = "block";
bmiValue.innerHTML = bmi.toFixed(1);
var category = "";
var color = "";
var rangeText = "";
if (bmi = 18.5 && bmi = 25 && bmi < 30) {
category = "Overweight";
color = "#f39c12";
rangeText = "A BMI of 25-29.9 indicates that you are slightly overweight. You may be advised to lose some weight for health reasons. You are recommended to talk to your doctor or a dietitian for advice.";
} else {
category = "Obese";
color = "#e74c3c";
rangeText = "A BMI of over 30 indicates that you are heavily overweight. Your health may be at risk if you do not lose weight. You are recommended to talk to your doctor or a dietitian for advice.";
}
bmiCategory.innerHTML = category;
bmiCategory.style.color = color;
bmiRangeInfo.innerHTML = rangeText;
resultBox.scrollIntoView({ behavior: 'smooth', block: 'nearest' });
}