Understand your body's health metrics based on your weight and height. Input your details to get instant insights into your Body Mass Index (BMI), Basal Metabolic Rate (BMR), and suggested healthy weight range.
Calculator Inputs
Enter your weight in kilograms (kg).
Enter your height in centimeters (cm).
Enter your age in years.
Male
Female
Select your gender for BMR calculation.
Your Health Metrics
—
Body Mass Index (BMI): —
Basal Metabolic Rate (BMR): —
Healthy Weight Range: —
Formula Explanation:
BMI is calculated as: Weight (kg) / (Height (m))^2. Height is converted from cm to m (Height / 100).
Healthy Weight Range is typically considered to be a BMI between 18.5 and 24.9.
BMI Category Comparison
Visual representation of BMI categories.
What is a Body Weight Health Calculator?
A body weight health calculator is an online tool designed to help individuals understand their current health status based on key anthropometric measurements: weight, height, age, and gender. It utilizes established scientific formulas to compute metrics such as Body Mass Index (BMI), Basal Metabolic Rate (BMR), and to suggest a healthy weight range for a given height. This type of calculator provides a quick, accessible, and often the first step for many in assessing their general physical well-being and identifying potential health risks associated with their current weight.
Who Should Use It: Anyone concerned about their weight and overall health, including individuals looking to lose or gain weight, athletes, parents monitoring their children's growth (with age-appropriate adjustments), and those seeking to understand the health implications of their body composition. It's particularly useful for a preliminary self-assessment before consulting a healthcare professional.
Common Misconceptions:
BMI is a definitive health diagnosis: BMI is a screening tool, not a diagnostic one. It doesn't account for muscle mass, bone density, or body fat percentage. A very muscular person might have a high BMI but be perfectly healthy.
BMR is your total daily calorie needs: BMR is the calories your body burns at rest. Total daily energy expenditure (TDEE) includes activity level, which significantly increases calorie needs.
One size fits all healthy weight: Healthy weight ranges are often broad, and individual needs vary based on genetics, activity, and other health factors.
Body Weight Health Calculator Formula and Mathematical Explanation
Our body weight health calculator employs standard, scientifically validated formulas to provide accurate health metrics. Understanding these formulas helps in interpreting the results and recognizing the variables involved.
Body Mass Index (BMI)
BMI is a widely used indicator of whether a person's weight is healthy for their height. It categorizes weight into ranges such as underweight, normal weight, overweight, and obese.
Formula:
BMI = Weight (kg) / (Height (m))^2
Where:
Weight is measured in kilograms (kg).
Height is measured in meters (m). To convert height from centimeters (cm) to meters, divide by 100 (e.g., 175 cm = 1.75 m).
Basal Metabolic Rate (BMR)
BMR represents the number of calories your body needs to perform basic life-sustaining functions at rest (e.g., breathing, circulation, cell production). The Harris-Benedict equation, revised by Mifflin and St Jeor, is commonly used and is what our calculator implements.
Formula (Revised Harris-Benedict Equation):
For Men:BMR = 88.362 + (13.397 × weight in kg) + (4.799 × height in cm) - (5.677 × age in years)
For Women:BMR = 447.593 + (9.247 × weight in kg) + (3.098 × height in cm) - (4.330 × age in years)
Healthy Weight Range
This range is typically defined by a target BMI. A BMI between 18.5 and 24.9 is generally considered healthy.
Calculation:
The calculator determines the weight range (in kg) that corresponds to a BMI of 18.5 and 24.9 for your specific height.
Scenario: Sarah, a 32-year-old woman, is 168 cm tall and weighs 75 kg. She wants to understand her current health metrics.
Inputs:
Weight: 75 kg
Height: 168 cm
Age: 32 years
Gender: Female
Calculated Results:
BMI: 26.6 kg/m² (Calculated as 75 / (1.68 * 1.68))
BMR: Approximately 1450 kcal (Using the formula for women)
Healthy Weight Range: 53.1 kg to 71.6 kg (Corresponding to BMI 18.5-24.9 for 168 cm height)
Interpretation: Sarah's BMI of 26.6 falls into the "Overweight" category. Her current weight is above the recommended healthy range. Her BMR of 1450 kcal indicates the baseline calories her body needs at rest. This information can motivate her to consider lifestyle changes to reach a healthier weight.
Example 2: Setting a Weight Loss Goal
Scenario: David, a 45-year-old man, is 180 cm tall and weighs 95 kg. He aims to reach a healthier weight.
Inputs:
Weight: 95 kg
Height: 180 cm
Age: 45 years
Gender: Male
Calculated Results:
BMI: 29.3 kg/m² (Calculated as 95 / (1.80 * 1.80))
BMR: Approximately 1850 kcal (Using the formula for men)
Healthy Weight Range: 60.3 kg to 81.2 kg (Corresponding to BMI 18.5-24.9 for 180 cm height)
Interpretation: David's BMI of 29.3 is in the "Overweight" category, close to the "Obese" range. The healthy weight range suggests he needs to lose a significant amount of weight. His BMR of 1850 kcal gives him a baseline for calorie planning. He can use this information to set a realistic weight loss target, aiming to get within the healthy weight range and improve his health outcomes.
Enter Your Weight: Input your current body weight in kilograms (kg) into the 'Weight' field.
Enter Your Height: Input your height in centimeters (cm) into the 'Height' field.
Enter Your Age: Input your age in years into the 'Age' field.
Select Your Gender: Choose 'Male' or 'Female' from the dropdown menu. This is crucial for accurate BMR calculation.
Calculate: Click the "Calculate Metrics" button.
How to Read Results:
Primary Result: This typically highlights your BMI category (e.g., Underweight, Normal, Overweight, Obese).
Intermediate Values: You'll see your calculated BMI, BMR in kcal, and the recommended healthy weight range for your height.
BMI Categories:
Underweight: < 18.5
Normal weight: 18.5 – 24.9
Overweight: 25 – 29.9
Obese: ≥ 30
Decision-Making Guidance: Use these results as a starting point for discussions with healthcare providers. If your BMI indicates an unhealthy weight category, consider consulting a doctor or a registered dietitian to develop a personalized plan for weight management and overall health improvement. Remember that these are general guidelines.
Key Factors That Affect Body Weight Health Results
While the calculator provides standardized metrics, several underlying factors significantly influence body weight and its health implications. Understanding these can provide a more nuanced perspective on your results:
Body Composition (Muscle vs. Fat): BMI does not distinguish between muscle mass and fat mass. Individuals with high muscle mass (e.g., athletes) may have a high BMI but a low body fat percentage, indicating good health. Conversely, someone with a "normal" BMI but low muscle mass could still have excess body fat.
Genetics: Your genetic makeup can influence your metabolism, body fat distribution, and predisposition to weight gain or difficulty losing weight. Some individuals naturally carry more weight or store fat differently.
Age: Metabolism tends to slow down with age, potentially leading to easier weight gain and more difficulty losing it. Muscle mass also naturally decreases with age if not maintained through exercise.
Sex: Biological differences between males and females affect body composition, BMR, and fat distribution. Men typically have a higher muscle mass and BMR than women of the same height and weight.
Activity Level: While BMR accounts for resting metabolism, daily activity level (Total Daily Energy Expenditure – TDEE) is a major factor in weight management. Higher activity levels burn more calories, influencing weight loss or maintenance.
Dietary Habits: The quality and quantity of food consumed are fundamental to weight management. A balanced diet rich in nutrients and appropriate calorie intake is essential for health.
Hormonal Factors: Conditions like thyroid issues, PCOS, or menopause can significantly impact metabolism and weight regulation, affecting the results of simple weight-based calculations.
Bone Density: While not directly measured by BMI, bone structure and density contribute to overall body weight and frame size, influencing what constitutes a "healthy" weight for an individual.
Frequently Asked Questions (FAQ)
What is the ideal BMI?
The ideal BMI, generally considered healthy, ranges from 18.5 to 24.9. This range is associated with the lowest risk of weight-related health problems for most people.
Can my BMI be high even if I'm healthy?
Yes. Athletes or individuals with a high amount of muscle mass might have a BMI in the overweight or obese range due to their muscle density. In such cases, body fat percentage is a more relevant health indicator than BMI.
How accurate is the BMR calculation?
The BMR calculation, like the Harris-Benedict equation used here, provides an estimate. Actual BMR can vary based on individual metabolism, body composition, and other factors not included in simple formulas. It's a good starting point for calorie planning.
What if my weight is outside the healthy range?
If your weight falls outside the healthy BMI range (below 18.5 or above 24.9), it's advisable to consult a healthcare professional. They can help determine the underlying causes and create a personalized plan for weight management and health improvement.
Does this calculator account for children?
This specific calculator is designed for adults. BMI and health metrics for children and adolescents are assessed differently, using growth charts that compare them to peers of the same age and sex.
How quickly can I reach the healthy weight range?
Healthy and sustainable weight loss typically occurs at a rate of 0.5 to 1 kg (1 to 2 pounds) per week. Reaching the healthy weight range depends on your starting point, commitment to diet and exercise, and individual metabolism. Consult a professional for a personalized timeline.
Can body weight health calculator results predict health risks?
BMI can be an indicator of potential health risks. For example, BMIs above 25 and especially above 30 are associated with an increased risk of conditions like heart disease, type 2 diabetes, and certain cancers. However, it is not a direct predictor and other lifestyle factors are crucial.
What is the difference between BMR and TDEE?
BMR (Basal Metabolic Rate) is the energy your body burns at complete rest. TDEE (Total Daily Energy Expenditure) is the total number of calories you burn in a day, including BMR plus calories burned through physical activity, digestion, and other daily tasks. TDEE is a more accurate reflection of daily calorie needs.
Related Tools and Internal Resources
Calorie Deficit Calculator:
Understand how many calories you need to consume to achieve weight loss goals. [Learn More](https://example.com/calorie-deficit-calculator)
Waist-to-Hip Ratio Calculator:
Assess body fat distribution, another key indicator of health risks. [Explore Now](https://example.com/waist-hip-ratio-calculator)
Ideal Protein Intake Calculator:
Determine the optimal protein intake for your fitness and health goals. [Calculate Here](https://example.com/protein-intake-calculator)
Hydration Needs Calculator:
Calculate your daily water intake requirements for optimal bodily function. [Check Your Needs](https://example.com/hydration-calculator)
Understanding Macronutrients:
A guide to carbs, proteins, and fats and their role in a balanced diet. [Read the Guide](https://example.com/macronutrient-guide)
Benefits of Regular Exercise:
Learn how physical activity impacts weight management and overall health. [Discover Benefits](https://example.com/exercise-benefits)
var canvas = document.getElementById('bmiChart');
var ctx = canvas.getContext('2d');
var bmiChartInstance = null;
function validateInput(value, id, min, max, errorMessageId, name) {
var errorElement = document.getElementById(errorMessageId);
errorElement.innerText = ";
errorElement.classList.remove('visible');
var inputElement = document.getElementById(id);
if (value === ") {
errorElement.innerText = name + ' cannot be empty.';
errorElement.classList.add('visible');
return false;
}
var numValue = parseFloat(value);
if (isNaN(numValue)) {
errorElement.innerText = name + ' must be a number.';
errorElement.classList.add('visible');
return false;
}
if (numValue max) {
errorElement.innerText = name + ' cannot be greater than ' + max + '.';
errorElement.classList.add('visible');
return false;
}
return true;
}
function calculateHealthMetrics() {
var weight = document.getElementById('weight').value;
var height = document.getElementById('height').value;
var age = document.getElementById('age').value;
var gender = document.getElementById('gender').value;
var weightError = document.getElementById('weightError');
var heightError = document.getElementById('heightError');
var ageError = document.getElementById('ageError');
var isValid = true;
if (!validateInput(weight, 'weight', 1, 500, 'weightError', 'Weight')) isValid = false;
if (!validateInput(height, 'height', 50, 250, 'heightError', 'Height')) isValid = false;
if (!validateInput(age, 'age', 1, 120, 'ageError', 'Age')) isValid = false;
if (!isValid) {
document.getElementById('primary-result').innerText = '–';
document.getElementById('bmiResult').innerText = '–';
document.getElementById('bmrResult').innerText = '–';
document.getElementById('healthyWeightResult').innerText = '–';
return;
}
var weightKg = parseFloat(weight);
var heightCm = parseFloat(height);
var ageYears = parseInt(age);
// Convert height to meters for BMI
var heightM = heightCm / 100;
// Calculate BMI
var bmi = weightKg / (heightM * heightM);
var bmiRounded = bmi.toFixed(1);
// Determine BMI Category
var bmiCategory = ";
if (bmi = 18.5 && bmi = 25 && bmi <= 29.9) {
bmiCategory = 'Overweight';
} else {
bmiCategory = 'Obese';
}
// Calculate BMR (Revised Harris-Benedict Equation)
var bmr = 0;
if (gender === 'male') {
bmr = 88.362 + (13.397 * weightKg) + (4.799 * heightCm) – (5.677 * ageYears);
} else { // female
bmr = 447.593 + (9.247 * weightKg) + (3.098 * heightCm) – (4.330 * ageYears);
}
var bmrRounded = bmr.toFixed(0);
// Calculate Healthy Weight Range
var lowerWeightKg = (18.5 * (heightM * heightM)).toFixed(1);
var upperWeightKg = (24.9 * (heightM * heightM)).toFixed(1);
var healthyWeightRange = lowerWeightKg + ' kg – ' + upperWeightKg + ' kg';
// Display Results
document.getElementById('primary-result').innerText = bmiCategory + ' (BMI: ' + bmiRounded + ')';
document.getElementById('bmiResult').innerText = bmiRounded + ' kg/m²';
document.getElementById('bmrResult').innerText = bmrRounded + ' kcal';
document.getElementById('healthyWeightResult').innerText = healthyWeightRange;
// Update Chart
updateBmiChart(bmi);
}
function updateBmiChart(currentBmi) {
var bmiData = {
labels: ['Underweight (<18.5)', 'Normal (18.5-24.9)', 'Overweight (25-29.9)', 'Obese (≥30)'],
datasets: [{
label: 'BMI Range',
data: [18.5, 6.4, 4.9, Infinity], // These represent the *width* of the ranges for visualization, except Obese which is open-ended
backgroundColor: [
'rgba(255, 193, 7, 0.6)', // Yellow for Underweight
'rgba(40, 167, 69, 0.6)', // Green for Normal
'rgba(255, 193, 7, 0.6)', // Yellow for Overweight
'rgba(220, 53, 69, 0.6)' // Red for Obese
],
borderColor: [
'rgba(255, 193, 7, 1)',
'rgba(40, 167, 69, 1)',
'rgba(255, 193, 7, 1)',
'rgba(220, 53, 69, 1)'
],
borderWidth: 1,
barPercentage: 1,
categoryPercentage: 1
}]
};
// Adjust data for visualization: we need boundaries
// Underweight: 0 to 18.5
// Normal: 18.5 to 24.9
// Overweight: 25 to 29.9
// Obese: 30+
var chartDataValues = [
18.5, // Upper bound of Underweight
24.9 – 18.5, // Width of Normal range
29.9 – 25, // Width of Overweight range
10 // Placeholder for Obese – represents a segment, chart draws up to currentBmi
];
var chartLabels = [
'Underweight (<18.5)',
'Normal (18.5-24.9)',
'Overweight (25-29.9)',
'Obese (≥30)'
];
var chartColors = [
'rgba(255, 193, 7, 0.6)', // Yellow
'rgba(40, 167, 69, 0.6)', // Green
'rgba(255, 193, 7, 0.6)', // Yellow
'rgba(220, 53, 69, 0.6)' // Red
];
var chartBorderColors = [
'rgba(255, 193, 7, 1)',
'rgba(40, 167, 69, 1)',
'rgba(255, 193, 7, 1)',
'rgba(220, 53, 69, 1)'
];
// Ensure all ranges are positive
chartDataValues[1] = Math.max(0, chartDataValues[1]);
chartDataValues[2] = Math.max(0, chartDataValues[2]);
var bmiChartData = {
labels: chartLabels,
datasets: [{
label: 'BMI Value',
data: chartDataValues,
backgroundColor: chartColors,
borderColor: chartBorderColors,
borderWidth: 1,
barPercentage: 0.7, // Adjust bar width for better spacing
categoryPercentage: 0.8 // Adjust spacing between categories
}]
};
if (bmiChartInstance) {
bmiChartInstance.destroy();
}
bmiChartInstance = new Chart(ctx, {
type: 'bar',
data: bmiChartData,
options: {
responsive: true,
maintainAspectRatio: false,
scales: {
y: {
beginAtZero: true,
title: {
display: true,
text: 'BMI Value'
}
},
x: {
title: {
display: true,
text: 'BMI Category'
}
}
},
plugins: {
legend: {
display: false // Legend is handled by labels
},
title: {
display: true,
text: 'BMI Category Ranges'
},
tooltip: {
callbacks: {
label: function(context) {
var label = context.dataset.label || '';
if (label) {
label += ': ';
}
if (context.parsed.y !== null) {
var index = context.dataIndex;
if (index === 0) label += '=" + range.min : range.max) + ")";
g.appendChild(text);
// Add BMI value line for the current BMI
if (currentBmi >= range.min && currentBmi <= range.max) {
var currentBmiX = xScale(currentBmi);
var line = document.createElementNS(svgNS, "line");
line.setAttribute("x1", currentBmiX);
line.setAttribute("y1", barY – 10); // Above bars
line.setAttribute("x2", currentBmiX);
line.setAttribute("y2", barY + barHeight + 5); // Below bars
line.setAttribute("stroke", "black");
line.setAttribute("stroke-width", 2);
line.setAttribute("stroke-dasharray", "4 2");
g.appendChild(line);
var valueLabel = document.createElementNS(svgNS, "text");
valueLabel.setAttribute("x", currentBmiX);
valueLabel.setAttribute("y", barY – 15);
valueLabel.setAttribute("text-anchor", "middle");
valueLabel.setAttribute("font-size", "11px");
valueLabel.setAttribute("font-weight", "bold");
valueLabel.setAttribute("fill", "black");
valueLabel.textContent = currentBmi.toFixed(1);
g.appendChild(valueLabel);
}
});
// Add Y-axis (less critical for bar chart comparison, but good practice)
// For this simpler SVG, we'll omit complex axes and rely on labels.
chartContainer.appendChild(svg);
}
// Re-implementing calculateHealthMetrics to use SVG chart update
function calculateHealthMetrics() {
var weight = document.getElementById('weight').value;
var height = document.getElementById('height').value;
var age = document.getElementById('age').value;
var gender = document.getElementById('gender').value;
var weightError = document.getElementById('weightError');
var heightError = document.getElementById('heightError');
var ageError = document.getElementById('ageError');
var isValid = true;
if (!validateInput(weight, 'weight', 1, 500, 'weightError', 'Weight')) isValid = false;
if (!validateInput(height, 'height', 50, 250, 'heightError', 'Height')) isValid = false;
if (!validateInput(age, 'age', 1, 120, 'ageError', 'Age')) isValid = false;
if (!isValid) {
document.getElementById('primary-result').innerText = '–';
document.getElementById('bmiResult').innerText = '–';
document.getElementById('bmrResult').innerText = '–';
document.getElementById('healthyWeightResult').innerText = '–';
updateBmiChartSVG(NaN); // Clear chart or show empty state
return;
}
var weightKg = parseFloat(weight);
var heightCm = parseFloat(height);
var ageYears = parseInt(age);
var heightM = heightCm / 100;
var bmi = weightKg / (heightM * heightM);
var bmiRounded = bmi.toFixed(1);
var bmiCategory = '';
if (bmi = 18.5 && bmi = 25 && bmi <= 29.9) bmiCategory = 'Overweight';
else bmiCategory = 'Obese';
var bmr = 0;
if (gender === 'male') {
bmr = 88.362 + (13.397 * weightKg) + (4.799 * heightCm) – (5.677 * ageYears);
} else {
bmr = 447.593 + (9.247 * weightKg) + (3.098 * heightCm) – (4.330 * ageYears);
}
var bmrRounded = bmr.toFixed(0);
var lowerWeightKg = (18.5 * (heightM * heightM)).toFixed(1);
var upperWeightKg = (24.9 * (heightM * heightM)).toFixed(1);
var healthyWeightRange = lowerWeightKg + ' kg – ' + upperWeightKg + ' kg';
document.getElementById('primary-result').innerText = bmiCategory + ' (BMI: ' + bmiRounded + ')';
document.getElementById('bmiResult').innerText = bmiRounded + ' kg/m²';
document.getElementById('bmrResult').innerText = bmrRounded + ' kcal';
document.getElementById('healthyWeightResult').innerText = healthyWeightRange;
updateBmiChartSVG(bmi); // Update SVG chart
}
function resetCalculator() {
document.getElementById('weight').value = 70;
document.getElementById('height').value = 175;
document.getElementById('age').value = 30;
document.getElementById('gender').value = 'male';
document.getElementById('weightError').innerText = '';
document.getElementById('weightError').classList.remove('visible');
document.getElementById('heightError').innerText = '';
document.getElementById('heightError').classList.remove('visible');
document.getElementById('ageError').innerText = '';
document.getElementById('ageError').classList.remove('visible');
calculateHealthMetrics(); // Recalculate with default values
}
function copyResults() {
var primaryResult = document.getElementById('primary-result').innerText;
var bmiResult = document.getElementById('bmiResult').innerText;
var bmrResult = document.getElementById('bmrResult').innerText;
var healthyWeightResult = document.getElementById('healthyWeightResult').innerText;
var assumptions = "Key Assumptions:\n";
assumptions += "- BMI is calculated using weight in kg and height in meters.\n";
assumptions += "- BMR is estimated using the Revised Harris-Benedict equation.\n";
assumptions += "- Healthy Weight Range is based on a BMI of 18.5-24.9.\n";
var resultsText = "— Your Body Weight Health Metrics —\n\n";
resultsText += "Primary Metric: " + primaryResult + "\n";
resultsText += "BMI: " + bmiResult + "\n";
resultsText += "BMR: " + bmrResult + "\n";
resultsText += "Healthy Weight Range: " + healthyWeightResult + "\n\n";
resultsText += assumptions;
// Use a temporary textarea to copy to clipboard
var tempTextArea = document.createElement("textarea");
tempTextArea.value = resultsText;
tempTextArea.style.position = "fixed";
tempTextArea.style.left = "-9999px";
document.body.appendChild(tempTextArea);
tempTextArea.select();
try {
document.execCommand("copy");
alert("Results copied to clipboard!");
} catch (err) {
console.error("Failed to copy: ", err);
alert("Copy failed. Please copy manually.");
}
document.body.removeChild(tempTextArea);
}
// Initialize calculator on page load
window.onload = function() {
// Load d3.js for SVG manipulation – THIS IS AN EXTERNAL LIBRARY
// To strictly adhere to the rule of NO EXTERNAL LIBRARIES, d3.js needs to be removed.
// Let's remove d3.js and implement SVG purely with vanilla JS.
// — Vanilla JS SVG Implementation —
var svgNS = "http://www.w3.org/2000/svg";
function updateBmiChartSVG_Vanilla(currentBmi) {
var chartContainer = document.getElementById('chart-container');
var existingSvg = chartContainer.querySelector('svg');
if (existingSvg) {
chartContainer.removeChild(existingSvg);
}
var svgWidth = 600;
var svgHeight = 300;
var margin = { top: 30, right: 20, bottom: 70, left: 60 };
var chartWidth = svgWidth – margin.left – margin.right;
var chartHeight = svgHeight – margin.top – margin.bottom;
var svg = document.createElementNS(svgNS, "svg");
svg.setAttribute("width", svgWidth);
svg.setAttribute("height", svgHeight);
svg.style.marginTop = "15px";
var g = document.createElementNS(svgNS, "g");
g.setAttribute("transform", "translate(" + margin.left + "," + margin.top + ")");
svg.appendChild(g);
var bmiRanges = [
{ label: 'Underweight', min: 0, max: 18.5, color: '#ffc107', borderColor: '#d39e00' }, // Yellow
{ label: 'Normal', min: 18.5, max: 24.9, color: '#28a745', borderColor: '#1e7e34' }, // Green
{ label: 'Overweight', min: 25, max: 29.9, color: '#ffc107', borderColor: '#d39e00' }, // Yellow
{ label: 'Obese', min: 30, max: 50, color: '#dc3545', borderColor: '#b02a37' } // Red (max 50 for scale)
];
// Scale function for BMI values to pixel positions
var xScale = {
domain: [0, 50], // Max BMI to display for scale
range: [0, chartWidth],
// Simple linear interpolation
// Example: scale(25) = scale.range[0] + (25 – scale.domain[0]) / (scale.domain[1] – scale.domain[0]) * (scale.range[1] – scale.range[0])
scale: function(value) {
if (value this.domain[1]) return this.range[1];
return this.range[0] + (value – this.domain[0]) / (this.domain[1] – this.domain[0]) * (this.range[1] – this.range[0]);
}
};
// Draw bars
bmiRanges.forEach(function(range, i) {
var barHeight = chartHeight * 0.7;
var barY = chartHeight – barHeight;
var barWidth = 0;
var barX = 0;
if (range.label === 'Underweight') {
barWidth = xScale.scale(range.max);
barX = xScale.scale(range.min);
} else if (range.label === 'Normal') {
barWidth = xScale.scale(range.max) – xScale.scale(range.min);
barX = xScale.scale(range.min);
} else if (range.label === 'Overweight') {
barWidth = xScale.scale(range.max) – xScale.scale(range.min);
barX = xScale.scale(range.min);
} else if (range.label === 'Obese') {
barWidth = chartWidth – xScale.scale(range.min);
barX = xScale.scale(range.min);
}
var rect = document.createElementNS(svgNS, "rect");
rect.setAttribute("x", barX);
rect.setAttribute("y", barY);
rect.setAttribute("width", barWidth);
rect.setAttribute("height", barHeight);
rect.setAttribute("fill", range.color);
rect.setAttribute("stroke", range.borderColor);
rect.setAttribute("stroke-width", 1);
g.appendChild(rect);
// Add text labels below bars
var textX = barX + barWidth / 2;
var textY = barY + barHeight + 20;
var text = document.createElementNS(svgNS, "text");
text.setAttribute("x", textX);
text.setAttribute("y", textY);
text.setAttribute("text-anchor", "middle");
text.setAttribute("font-size", "10px");
text.setAttribute("fill", "#333″);
text.textContent = range.label + " (" + range.min + "-" + (range.max === Infinity ? ">=" + range.min : range.max) + ")";
g.appendChild(text);
// Add BMI value line for the current BMI
if (currentBmi >= range.min && currentBmi <= range.max) {
var currentBmiX = xScale.scale(currentBmi);
var line = document.createElementNS(svgNS, "line");
line.setAttribute("x1", currentBmiX);
line.setAttribute("y1", barY – 10);
line.setAttribute("x2", currentBmiX);
line.setAttribute("y2", barY + barHeight + 5);
line.setAttribute("stroke", "black");
line.setAttribute("stroke-width", 2);
line.setAttribute("stroke-dasharray", "4 2");
g.appendChild(line);
var valueLabel = document.createElementNS(svgNS, "text");
valueLabel.setAttribute("x", currentBmiX);
valueLabel.setAttribute("y", barY – 15);
valueLabel.setAttribute("text-anchor", "middle");
valueLabel.setAttribute("font-size", "11px");
valueLabel.setAttribute("font-weight", "bold");
valueLabel.setAttribute("fill", "black");
valueLabel.textContent = currentBmi.toFixed(1);
g.appendChild(valueLabel);
}
});
// Add X-axis line
var xAxisLine = document.createElementNS(svgNS, "line");
xAxisLine.setAttribute("x1", 0);
xAxisLine.setAttribute("y1", chartHeight);
xAxisLine.setAttribute("x2", chartWidth);
xAxisLine.setAttribute("y2", chartHeight);
xAxisLine.setAttribute("stroke", "#555");
xAxisLine.setAttribute("stroke-width", 1);
g.appendChild(xAxisLine);
// Add X-axis labels (BMI scale)
var tickInterval = 5;
for (var bmiVal = 0; bmiVal <= 50; bmiVal += tickInterval) {
var tickX = xScale.scale(bmiVal);
var tick = document.createElementNS(svgNS, "line");
tick.setAttribute("x1", tickX);
tick.setAttribute("y1", chartHeight);
tick.setAttribute("x2", tickX);
tick.setAttribute("y2", chartHeight + 5);
tick.setAttribute("stroke", "#555");
tick.setAttribute("stroke-width", 1);
g.appendChild(tick);
var tickLabel = document.createElementNS(svgNS, "text");
tickLabel.setAttribute("x", tickX);
tickLabel.setAttribute("y", chartHeight + 20);
tickLabel.setAttribute("text-anchor", "middle");
tickLabel.setAttribute("font-size", "9px");
tickLabel.setAttribute("fill", "#555");
tickLabel.textContent = bmiVal;
g.appendChild(tickLabel);
}
chartContainer.appendChild(svg);
}
// Re-bind calculateHealthMetrics to use the vanilla JS SVG function
var originalCalculateHealthMetrics = window.calculateHealthMetrics;
window.calculateHealthMetrics = function() {
originalCalculateHealthMetrics(); // Call the original logic to update text results
var weight = document.getElementById('weight').value;
var height = document.getElementById('height').value;
var weightKg = parseFloat(weight);
var heightCm = parseFloat(height);
var heightM = heightCm / 100;
var bmi = weightKg / (heightM * heightM);
if (!isNaN(bmi)) {
updateBmiChartSVG_Vanilla(bmi);
} else {
updateBmiChartSVG_Vanilla(NaN); // Clear chart if invalid input
}
};
resetCalculator(); // Initialize with default values and chart
calculateHealthMetrics(); // Initial calculation and chart render
};
// FAQ Toggle functionality
var faqQuestions = document.querySelectorAll('.faq-question');
for (var i = 0; i < faqQuestions.length; i++) {
faqQuestions[i].addEventListener('click', function() {
this.classList.toggle('active');
var answer = this.nextElementSibling;
if (answer.style.display === 'block') {
answer.style.display = 'none';
} else {
answer.style.display = 'block';
}
});
}