.cdc-bmi-calculator-wrapper {
font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
max-width: 800px;
margin: 20px auto;
padding: 20px;
border: 1px solid #e0e0e0;
border-radius: 8px;
background-color: #ffffff;
box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}
.cdc-bmi-calculator-wrapper h2 {
color: #0056b3;
text-align: center;
margin-bottom: 25px;
font-size: 1.8em;
}
.cdc-bmi-calculator-wrapper h3 {
color: #333;
font-size: 1.4em;
margin-top: 20px;
}
.cdc-bmi-calculator-wrapper p {
line-height: 1.6;
color: #555;
}
.cdc-bmi-calculator-wrapper .calculator-inputs label {
display: inline-block;
margin-bottom: 8px;
font-weight: bold;
color: #444;
width: 120px; /* Align labels */
}
.cdc-bmi-calculator-wrapper .calculator-inputs input[type="number"] {
width: 100px;
padding: 8px;
margin-bottom: 10px;
border: 1px solid #ccc;
border-radius: 4px;
box-sizing: border-box;
}
.cdc-bmi-calculator-wrapper .calculator-inputs input[type="radio"] {
margin-right: 5px;
}
.cdc-bmi-calculator-wrapper .calculator-inputs button {
background-color: #007bff;
color: white;
padding: 12px 20px;
border: none;
border-radius: 5px;
cursor: pointer;
font-size: 1.1em;
display: block;
width: 100%;
margin-top: 20px;
transition: background-color 0.3s ease;
}
.cdc-bmi-calculator-wrapper .calculator-inputs button:hover {
background-color: #0056b3;
}
.cdc-bmi-calculator-wrapper #bmiResult {
margin-top: 30px;
padding: 20px;
border: 1px solid #d4edda;
background-color: #dff0d8;
border-radius: 8px;
text-align: center;
color: #155724;
font-size: 1.1em;
}
.cdc-bmi-calculator-wrapper #bmiResult h3 {
color: #155724;
margin-top: 0;
font-size: 1.6em;
}
.cdc-bmi-calculator-wrapper #bmiResult p {
margin-bottom: 5px;
color: #155724;
}
.cdc-bmi-calculator-wrapper #bmiResult p.error {
color: #721c24;
background-color: #f8d7da;
border-color: #f5c6cb;
padding: 10px;
border-radius: 5px;
}
.cdc-bmi-calculator-wrapper .unit-system-selection {
margin-bottom: 20px;
padding: 10px;
background-color: #f0f8ff;
border: 1px solid #cce5ff;
border-radius: 5px;
}
.cdc-bmi-calculator-wrapper .unit-system-selection label {
margin-right: 15px;
font-weight: normal;
width: auto;
}
.cdc-bmi-calculator-wrapper .input-group {
border: 1px solid #eee;
padding: 15px;
margin-bottom: 15px;
border-radius: 5px;
background-color: #fdfdfd;
}
.cdc-bmi-calculator-wrapper .input-group p {
font-weight: bold;
margin-top: 0;
color: #0056b3;
}
.cdc-bmi-calculator-wrapper .article-content {
margin-top: 40px;
border-top: 1px solid #e0e0e0;
padding-top: 30px;
}
.cdc-bmi-calculator-wrapper .article-content h3 {
color: #0056b3;
font-size: 1.5em;
margin-bottom: 15px;
}
.cdc-bmi-calculator-wrapper .article-content ul {
list-style-type: disc;
margin-left: 20px;
color: #555;
}
.cdc-bmi-calculator-wrapper .article-content li {
margin-bottom: 8px;
}
function calculateBMI() {
var bmiResultDiv = document.getElementById("bmiResult");
bmiResultDiv.innerHTML = ""; // Clear previous results
var weight, height;
var unitSystem = document.querySelector('input[name="unitSystem"]:checked').value;
var bmi;
var category;
if (unitSystem === "us") {
var weightLbs = parseFloat(document.getElementById("weightLbs").value);
var heightFeet = parseFloat(document.getElementById("heightFeet").value);
var heightInches = parseFloat(document.getElementById("heightInches").value);
if (isNaN(weightLbs) || isNaN(heightFeet) || isNaN(heightInches) || weightLbs <= 0 || heightFeet < 0 || heightInches < 0 || (heightFeet === 0 && heightInches === 0)) {
bmiResultDiv.innerHTML = "Please enter valid positive numbers for weight and height.";
return;
}
var totalInches = (heightFeet * 12) + heightInches;
if (totalInches === 0) { // Edge case: height is 0
bmiResultDiv.innerHTML = "Height cannot be zero.";
return;
}
bmi = (weightLbs / (totalInches * totalInches)) * 703;
} else { // metric
var weightKg = parseFloat(document.getElementById("weightKg").value);
var heightCm = parseFloat(document.getElementById("heightCm").value);
if (isNaN(weightKg) || isNaN(heightCm) || weightKg <= 0 || heightCm <= 0) {
bmiResultDiv.innerHTML = "Please enter valid positive numbers for weight and height.";
return;
}
var heightMeters = heightCm / 100;
if (heightMeters === 0) { // Edge case: height is 0
bmiResultDiv.innerHTML = "Height cannot be zero.";
return;
}
bmi = weightKg / (heightMeters * heightMeters);
}
if (bmi = 18.5 && bmi = 25 && bmi <= 29.9) {
category = "Overweight";
} else {
category = "Obesity";
}
bmiResultDiv.innerHTML = "
";
}
function toggleUnitSystem() {
var usInputs = document.getElementById("usCustomaryInputs");
var metricInputs = document.getElementById("metricInputs");
var usRadio = document.getElementById("unitSystemUS");
if (usRadio.checked) {
usInputs.style.display = "block";
metricInputs.style.display = "none";
} else {
usInputs.style.display = "none";
metricInputs.style.display = "block";
}
}
// Initialize the display based on default radio button on page load
document.addEventListener('DOMContentLoaded', function() {
toggleUnitSystem();
});
Understanding Your BMI: A Guide from the CDC
The Body Mass Index (BMI) is a simple, inexpensive, and non-invasive screening tool used by the Centers for Disease Control and Prevention (CDC) and other health organizations to categorize an individual's weight relative to their height. It's a widely used indicator of potential weight problems for adults, but it's important to understand what it means and its limitations.
How is BMI Calculated?
BMI is calculated using a straightforward formula based on your weight and height:
- Metric Formula: BMI = weight (kg) / [height (m)]2
- US Customary Formula: BMI = [weight (lbs) / [height (in)]2] x 703
Our calculator above allows you to input your measurements in either US customary units (pounds, feet, and inches) or metric units (kilograms and centimeters) and automatically performs the correct calculation.
BMI Categories for Adults (Ages 20 and Older)
The CDC defines BMI categories for adults as follows:
- Underweight: Less than 18.5
- Normal weight: 18.5 – 24.9
- Overweight: 25.0 – 29.9
- Obesity: 30.0 or greater
These categories are used as a general guide to assess health risks associated with weight. For example, individuals with a BMI in the "Overweight" or "Obesity" categories may be at increased risk for certain health conditions.
Why is BMI Important?
A high BMI can be an indicator of high body fatness, which can lead to various health problems, including:
- Heart disease
- High blood pressure
- Type 2 diabetes
- Gallstones
- Breathing problems (e.g., sleep apnea)
- Certain cancers
Conversely, a very low BMI can also indicate health risks, such as malnutrition, weakened immune function, and osteoporosis.
Limitations of BMI
While BMI is a useful screening tool, it has limitations and should not be used as the sole diagnostic measure of an individual's health. It does not directly measure body fat or distinguish between fat and muscle mass. Therefore:
- Athletes and very muscular individuals may have a high BMI without having high body fat.
- Older adults may have a normal BMI but have less muscle mass and more body fat than younger adults.
- Different ethnic groups may have different associations between BMI, body fat, and health risk.
- Children and adolescents use different BMI charts that account for age and sex. This calculator is for adults only.
For these reasons, the CDC emphasizes that BMI should be considered alongside other health assessments, such as waist circumference, diet, physical activity levels, family history, and other health screenings.
Next Steps
If your BMI falls outside the "Normal weight" range, it's recommended to consult with a healthcare provider. They can perform a comprehensive health assessment, discuss your individual risk factors, and help you develop a personalized plan for maintaining or achieving a healthy weight.
Remember, BMI is just one piece of the puzzle in understanding your overall health.