Body Fat Percentage Calculator
Estimate your body composition accurately.
Calculate Your Body Fat Percentage
Enter your age in years.
Male
Female
Select your biological gender.
Enter your height in centimeters (cm).
Enter your weight in kilograms (kg).
Measure around your waist at navel level (cm).
Measure around the widest part of your hips (cm). Leave blank if male.
Measure around the base of your neck (cm).
Your Results
–.–%
Estimated Body Fat Percentage
This calculator uses the US Navy method (or variations) for body fat estimation, which correlates body measurements with body fat percentage. The exact formula differs slightly for males and females.
Body Fat Percentage Distribution by Category
| Category | Men (%) | Women (%) |
|---|---|---|
| Essential Fat | 2-5% | 10-13% |
| Athletes | 6-13% | 14-20% |
| Fitness | 14-17% | 21-24% |
| Average | 18-24% | 25-31% |
| Obese | 25%+ | 32%+ |
What is Body Fat Percentage?
Body fat percentage is a measurement expressing what proportion of your total body weight is composed of fat. This is a more accurate indicator of health and fitness than simple body weight or Body Mass Index (BMI), as it distinguishes between lean mass (muscle, bone, organs) and fat mass. Understanding your body fat percentage is crucial for setting realistic fitness goals, assessing health risks, and monitoring progress towards a healthier lifestyle. It helps differentiate between being "skinny" and being "fit."
Who Should Use This Calculator?
Anyone interested in understanding their body composition can benefit from this calculator. This includes:
- Individuals starting or maintaining a fitness program.
- People aiming for weight loss or muscle gain.
- Athletes seeking to optimize performance.
- Anyone concerned about their health status related to body composition.
- Individuals looking for a more nuanced health metric than BMI.
Common Misconceptions
Several myths surround body fat percentage:
- "Low body fat is always best": While a healthy range is important, extremely low body fat can be detrimental to health, impacting hormone production, energy levels, and immune function.
- "You can spot-reduce fat": Fat loss occurs systemically, not from specific areas. Targeted exercises build muscle, which can improve the appearance of a body area, but don't directly burn fat from there.
- "BMI is a better health indicator": BMI doesn't distinguish between muscle and fat. A very muscular person might have a high BMI but be very healthy, while someone with low muscle mass and high body fat could have a "healthy" BMI but be at risk.
Body Fat Percentage Formula and Mathematical Explanation
This calculator primarily uses a common estimation formula, often referred to as the U.S. Navy Body Fat Percentage formula, or variations thereof. This method is widely used due to its simplicity and reasonable accuracy for general estimations, relying on easily obtainable body measurements.
The Formula (Simplified Overview)
The core idea is to relate body measurements to lean body mass and fat mass. For men, waist circumference is a key factor, while for women, hip circumference is also considered alongside waist and neck.
For Men:
Body Fat % = 495 / ( [1.0324 – (0.19077 * log10(Waist – Neck))] + 0.15456 ) – 450
For Women:
Body Fat % = 495 / ( [1.29579 – (0.35004 * log10(Hip + Waist – Neck))] + 0.22100 ) – 450
Note: Age and Height can be used in more complex BIA (Bioelectrical Impedance Analysis) or other methods, but for this specific measurement-based calculator, they primarily serve to contextualize results and inform estimations, though some variations incorporate them. This calculator uses a direct measurement formula and provides age/gender as essential parameters for gender-specific calculations.
Variable Explanations
Let's break down the key variables used in the calculation:
| Variable | Meaning | Unit | Typical Range |
|---|---|---|---|
| Age | User's age in years. | Years | 1 – 120 |
| Gender | Biological sex of the user. | Category | Male, Female |
| Height | User's height. Used for context and potential alternative formulas. | cm | 50 – 250 |
| Weight | User's body weight. Crucial for relating measurements to overall mass. | kg | 10 – 500 |
| Waist Circumference | Measurement around the narrowest part of the torso, typically at navel level. Crucial indicator of abdominal fat. | cm | 30 – 200 |
| Hip Circumference | Measurement around the widest part of the hips. Primarily used for women. | cm | 50 – 200 |
| Neck Circumference | Measurement around the base of the neck. Used in some formulas to adjust for frame size. | cm | 20 – 70 |
| log10() | Base-10 logarithm function. A mathematical operation used in the formula. | N/A | N/A |
| Body Fat % | The final calculated percentage of body fat relative to total body weight. | % | 1 – 70+ |
Practical Examples (Real-World Use Cases)
Example 1: A Fit Male
Inputs:
- Age: 35
- Gender: Male
- Height: 180 cm
- Weight: 75 kg
- Waist Circumference: 80 cm
- Neck Circumference: 37 cm
- Hip Circumference: (Not used for males)
Calculation (Using the simplified US Navy formula for Men):
log10(Waist – Neck) = log10(80 – 37) = log10(43) ≈ 1.6335
Body Fat % = 495 / ( [1.0324 – (0.19077 * 1.6335)] + 0.15456 ) – 450
Body Fat % = 495 / ( [1.0324 – 0.3116] + 0.15456 ) – 450
Body Fat % = 495 / ( 0.7208 + 0.15456 ) – 450
Body Fat % = 495 / 0.87536 – 450
Body Fat % ≈ 565.47 – 450 ≈ 11.5%
Result Interpretation: A body fat percentage of 11.5% for a 35-year-old male falls within the "Athletes" or "Fitness" category. This indicates a lean physique with good muscle definition, suggesting a consistent training regimen and healthy diet.
Example 2: An Average Female
Inputs:
- Age: 45
- Gender: Female
- Height: 165 cm
- Weight: 65 kg
- Waist Circumference: 78 cm
- Hip Circumference: 102 cm
- Neck Circumference: 35 cm
Calculation (Using the simplified US Navy formula for Women):
log10(Hip + Waist – Neck) = log10(102 + 78 – 35) = log10(145) ≈ 2.1614
Body Fat % = 495 / ( [1.29579 – (0.35004 * 2.1614)] + 0.22100 ) – 450
Body Fat % = 495 / ( [1.29579 – 0.7570] + 0.22100 ) – 450
Body Fat % = 495 / ( 0.53879 + 0.22100 ) – 450
Body Fat % = 495 / 0.75979 – 450
Body Fat % ≈ 651.37 – 450 ≈ 20.4%
Result Interpretation: A body fat percentage of 20.4% for a 45-year-old female falls within the "Fitness" category. This suggests a healthy body composition, likely indicating regular physical activity and a balanced diet. It's a good position for overall health and well-being.
How to Use This Body Fat Percentage Calculator
Using our calculator is straightforward and designed for ease of use. Follow these steps to get your body fat estimate:
-
Gather Your Measurements: You'll need a flexible measuring tape. Ensure you are measuring on bare skin or very thin clothing for accuracy.
- Age, Gender, Height, Weight: Input these basic details as accurately as possible.
- Waist: Measure around your waist at the level of your navel. Exhale naturally before measuring.
- Hip (Women): Measure around the fullest part of your hips and buttocks.
- Neck: Measure around the base of your neck, just below the Adam's apple.
- Enter Your Data: Input the collected measurements into the respective fields in the calculator. Pay attention to the units (cm for measurements, kg for weight).
- Click Calculate: Once all relevant fields are filled, click the "Calculate" button.
- Review Your Results: The calculator will display your estimated Body Fat Percentage prominently. It will also show intermediate values like calculated lean body mass and fat mass, along with key assumptions made by the formula.
- Interpret Your Score: Compare your result to the provided body fat percentage categories table to understand where you stand (e.g., Average, Fitness, Athletes). Consider your age and gender as reference points.
- Use the Reset Button: If you need to start over or correct an entry, click the "Reset" button to clear all fields.
- Copy Results: Use the "Copy Results" button to save or share your calculated data and key metrics.
How to Read Results
The primary result is your Estimated Body Fat Percentage. This is the most critical number. The intermediate results (like Lean Body Mass and Fat Mass) provide further insight into your body composition. For instance, knowing your Fat Mass helps you quantify how much fat you might need to lose to reach a target body fat percentage.
Decision-Making Guidance
Your body fat percentage can guide your health and fitness decisions:
- If your percentage is high: Focus on a combination of cardiovascular exercise, strength training, and dietary adjustments to reduce body fat.
- If your percentage is in the average or fitness range: Maintain your current healthy habits. Consider setting goals for body recomposition (reducing fat while maintaining/increasing muscle).
- If your percentage is very low: Ensure you are not undereating or overtraining. Consult with a healthcare professional or dietitian if you have concerns about energy levels or hormonal health.
Remember, this calculator provides an estimate. For the most accurate assessment, consider consulting with a fitness professional or healthcare provider.
Key Factors That Affect Body Fat Percentage Results
While the formulas used by this calculator are designed for accuracy, several real-world factors can influence the actual body fat percentage and the accuracy of the estimation:
- Measurement Accuracy: This is paramount. Incorrectly measuring waist, hip, or neck circumference by even a centimeter can lead to significant variations in the final percentage. Ensure the tape is snug but not digging into the skin, and measure at the specified anatomical locations.
- Body Fat Distribution: People store fat differently. Some tend to carry more fat abdominally (which affects waist measurement significantly), while others store it more subcutaneously. Formulas like the US Navy method try to account for this, but individual variations exist.
- Hydration Levels: Significant fluctuations in body water can temporarily affect weight and, to a lesser extent, measurements, potentially skewing results if measurements are taken during periods of extreme dehydration or water retention.
- Muscle Mass vs. Fat Mass: While this calculator estimates fat mass, it's derived from total weight and measurements. Very high muscle mass can sometimes lead to slightly higher estimations of body fat with certain formulas, as muscle is denser than fat and contributes to overall size. However, for the US Navy method, it's generally quite good.
- Frame Size and Bone Density: The formulas don't explicitly measure frame size, but neck and wrist measurements (though not used in the primary calc here) are sometimes incorporated in other methods to estimate skeletal structure. This calculator relies more on girth measurements.
- Age and Hormonal Changes: As people age, body composition naturally changes, often with a tendency to lose muscle mass and gain fat, especially around the midsection. Hormonal shifts (e.g., menopause in women) can also influence fat distribution and body composition, impacting measurement results.
- Genetics: Genetic predispositions play a role in how your body stores and utilizes fat, influencing your overall body composition independent of diet and exercise alone.
Frequently Asked Questions (FAQ)
Q1: How accurate is this body fat calculator?
A: This calculator uses widely accepted formulas (like the US Navy method) that provide a good estimation. However, it's not as precise as methods like DEXA scans or hydrostatic weighing. Accuracy depends heavily on the precision of your measurements.
Q2: Can I use this calculator if I'm pregnant?
A: No, this calculator is not suitable for use during pregnancy. Hormonal changes and fluid retention significantly alter body measurements, making the results inaccurate and potentially misleading.
Q3: What if my hip measurement is significantly different from my waist?
A: This is common and expected. For women, a larger hip measurement relative to waist can be indicative of lower visceral fat, which is generally considered healthier. The formula accounts for this ratio.
Q4: Does the calculator work for children?
A: This calculator is designed for adults. Body composition and measurement standards differ significantly for children and adolescents. Consult with a pediatrician or healthcare professional for child-specific assessments.
Q5: How often should I use this calculator?
A: For tracking progress, using it every 1-3 months is usually sufficient. Use it consistently under similar conditions (e.g., same time of day, similar hydration levels) for the most reliable comparison over time.
Q6: What is considered "essential fat"?
A: Essential fat is the minimum amount of fat the body needs for vital physiological functions, including hormone regulation, organ protection, and temperature control. It's crucial for survival and health.
Q7: Can I use inches and pounds instead of cm and kg?
A: This calculator requires inputs in centimeters (cm) for height and circumference measurements, and kilograms (kg) for weight. You'll need to convert your measurements before entering them.
Q8: What if I have a very muscular build?
A: While this method is generally robust, extremely high muscle mass can sometimes slightly skew results in measurement-based calculators. However, it's still a much better indicator than BMI. If you suspect significant discrepancies, consider other assessment methods.
Related Tools and Internal Resources
- BMI CalculatorCalculate your Body Mass Index (BMI) and understand its limitations compared to body fat percentage.
- Basal Metabolic Rate (BMR) CalculatorEstimate the number of calories your body burns at rest, crucial for weight management.
- Ideal Body Weight CalculatorGet an estimate of your target weight range based on various formulas.
- Understanding Body CompositionLearn more about different methods for assessing body fat and lean mass.
- Healthy Eating PrinciplesDiscover tips and guidelines for a balanced diet to support your fitness goals.
- Benefits of Regular ExerciseExplore the numerous advantages of incorporating physical activity into your routine.
Fat Mass" + fatMass + " kg
";
intermediateHtml += "Lean Body Mass" + leanBodyMass + " kg
";
intermediateHtml += "Estimated BMI" + (weight / ((height / 100) * (height / 100))).toFixed(1) + "
";
document.getElementById("intermediateResults").innerHTML = intermediateHtml;
var assumptionsHtml = "Key Assumptions";
assumptions.push("Measurements taken accurately");
assumptions.push("Standard formula applied");
for (var i = 0; i < assumptions.length; i++) {
assumptionsHtml += "" + assumptions[i] + "";
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assumptionsHtml += "
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document.getElementById("assumptions").innerHTML = assumptionsHtml;
document.querySelector(".formula-explanation").innerHTML = "This calculator uses the " + formulaUsed.split(":")[0] + " formula: " + formulaUsed.split(":")[1].trim() + "";
updateChart(bodyFatPercent, gender);
}
function resetForm() {
document.getElementById("age").value = "";
document.getElementById("gender").value = "male";
document.getElementById("height").value = "";
document.getElementById("weight").value = "";
document.getElementById("waist").value = "";
document.getElementById("hip").value = "";
document.getElementById("neck").value = "";
document.getElementById("ageError").innerText = "";
document.getElementById("heightError").innerText = "";
document.getElementById("weightError").innerText = "";
document.getElementById("waistError").innerText = "";
document.getElementById("hipError").innerText = "";
document.getElementById("neckError").innerText = "";
document.getElementById("bodyFatPercentage").innerText = "–.–%";
document.getElementById("primaryResultContainer").style.display = "none";
document.getElementById("intermediateResults").innerHTML = "";
document.getElementById("assumptions").innerHTML = "";
document.querySelector(".formula-explanation").innerHTML = "This calculator uses the US Navy method (or variations) for body fat estimation, which correlates body measurements with body fat percentage. The exact formula differs slightly for males and females.";
// Reset chart data
if (chartInstance) {
chartInstance.data.datasets[0].data = [0, 0, 0, 0, 0];
chartInstance.update();
}
}
function copyResults() {
var bodyFat = document.getElementById("bodyFatPercentage").innerText;
var intermediates = document.getElementById("intermediateResults").innerText.split("kg").join(" kg\n").replace(/Estimated BMI/g, "\nEstimated BMI");
var assumptions = document.getElementById("assumptions").innerText.replace(/Key Assumptions/g, "\nKey Assumptions:");
var resultText = "— Body Fat Percentage Results —\n\n";
resultText += "Estimated Body Fat Percentage: " + bodyFat + "\n";
resultText += intermediates + "\n";
resultText += assumptions;
resultText += "\n(Calculated using US Navy Method)";
var textArea = document.createElement("textarea");
textArea.value = resultText;
document.body.appendChild(textArea);
textArea.select();
try {
var successful = document.execCommand('copy');
var msg = successful ? 'Results copied!' : 'Copying failed';
// Optional: Show a temporary message to the user
console.log(msg);
} catch (err) {
console.log('Oops, unable to copy');
}
document.body.removeChild(textArea);
}
function updateChart(bodyFatPercent, gender) {
var ctx = document.getElementById('bodyFatChart').getContext('2d');
// Define categories and their ranges based on gender
var categories = {
essential: { label: "Essential Fat", value: 3, color: "#FF6347" }, // Red
athletes: { label: "Athletes", value: 9, color: "#FFD700" }, // Gold
fitness: { label: "Fitness", value: 16, color: "#32CD32" }, // Lime Green
average: { label: "Average", value: 22, color: "#00BFFF" }, // Deep Sky Blue
obese: { label: "Obese", value: 30, color: "#800080" } // Purple
};
var maleRanges = {
essential: [2, 5],
athletes: [6, 13],
fitness: [14, 17],
average: [18, 24],
obese: [25, 100]
};
var femaleRanges = {
essential: [10, 13],
athletes: [14, 20],
fitness: [21, 24],
average: [25, 31],
obese: [32, 100]
};
var ranges = (gender === 'male') ? maleRanges : femaleRanges;
var dataSeries = [];
var labels = [];
var backgroundColors = [];
var bfP = parseFloat(bodyFatPercent);
// Assign a category based on the calculated percentage
var assignedCategory = "Unknown";
var assignedColor = "#ccc"; // Default grey
if (bfP <= ranges.essential[1]) {
assignedCategory = categories.essential.label;
assignedColor = categories.essential.color;
} else if (bfP <= ranges.athletes[1]) {
assignedCategory = categories.athletes.label;
assignedColor = categories.athletes.color;
} else if (bfP <= ranges.fitness[1]) {
assignedCategory = categories.fitness.label;
assignedColor = categories.fitness.color;
} else if (bfP 0) {
data.push(segmentValue);
chartLabels.push(categoryName.charAt(0).toUpperCase() + categoryName.slice(1));
colors.push(categories[categoryName].color);
currentMax = range[1];
}
}
// If calculated BF% is lower than the first range, add a segment for it
if (bfP < ranges[Object.keys(ranges)[0]][0]) {
data.unshift(bfP);
chartLabels.unshift("Your BF%");
colors.unshift(assignedColor);
} else {
// Add user's BF% as a marker or a segment, depending on how we want to visualize
// For simplicity, let's just add the segment value up to BF% and mark it.
data.push(bfP – currentMax); // This might be negative if BF% is in a lower category
chartLabels.push("Your BF%");
colors.push(assignedColor);
// We need to adjust ranges if bfP falls into a lower category
}
// Simplified approach for the chart: show the 5 categories and highlight the user's result point.
// Create a bar chart where each bar represents a category, and a marker shows the user's BF%.
var chartData = [];
var chartColors = [];
var chartLabelsList = [];
var sortedCategories = Object.keys(ranges).map(function(key) {
return { key: key, range: ranges[key], color: categories[key].color, label: categories[key].label };
});
sortedCategories.forEach(function(cat) {
chartData.push(cat.range[1]); // Use upper bound for bar height
chartLabelsList.push(cat.label);
chartColors.push(cat.color);
});
// Find the user's category and its upper bound
var userCategoryUpperBound = 0;
var userCategoryColor = "#ccc";
var userCategoryLabel = "Your BF%";
if (bfP <= maleRanges.essential[1] && gender === 'male' || bfP <= femaleRanges.essential[1] && gender === 'female') {
userCategoryUpperBound = maleRanges.essential[1]; userCategoryColor = maleRanges.color;
} else if (bfP <= maleRanges.athletes[1] && gender === 'male' || bfP <= femaleRanges.athletes[1] && gender === 'female') {
userCategoryUpperBound = maleRanges.athletes[1]; userCategoryColor = maleRanges.color;
} else if (bfP <= maleRanges.fitness[1] && gender === 'male' || bfP <= femaleRanges.fitness[1] && gender === 'female') {
userCategoryUpperBound = maleRanges.fitness[1]; userCategoryColor = maleRanges.color;
} else if (bfP <= maleRanges.average[1] && gender === 'male' || bfP <= femaleRanges.average[1] && gender === 'female') {
userCategoryUpperBound = maleRanges.average[1]; userCategoryColor = maleRanges.color;
} else {
userCategoryUpperBound = maleRanges.obese[1]; userCategoryColor = maleRanges.color;
}
// Let's draw a bar chart representing the categories and add a marker for the user's BF%
var categoryMaxValues = [];
var categoryLabels = [];
var categoryColors = [];
for (var categoryKey in ranges) {
categoryMaxValues.push(ranges[categoryKey][1]); // Upper bound of the category
categoryLabels.push(categories[categoryKey].label);
categoryColors.push(categories[categoryKey].color);
}
// Ensure data is sorted by value for plotting
var chartDataPoints = [];
for(var i = 0; i < categoryLabels.length; i++) {
chartDataPoints.push({
label: categoryLabels[i],
value: categoryMaxValues[i],
color: categoryColors[i]
});
}
chartDataPoints.sort(function(a, b) { return a.value – b.value; });
if (chartInstance) {
chartInstance.destroy();
}
var userBF = parseFloat(bodyFatPercent);
var chartMaxY = Math.max(…categoryMaxValues, userBF) * 1.1; // Max value for Y axis
// Prepare datasets for a stacked bar chart showing ranges, and a line/point for user BF%
var datasets = [{
label: 'Category Upper Limit (%)',
data: categoryMaxValues, // Use upper bounds for stacking
backgroundColor: categoryColors,
borderColor: '#fff',
borderWidth: 1
}];
// Create a second dataset for the marker line/point
// This dataset will have the user's BF% at their respective category index, or across the chart
// For simplicity, let's try a simple bar chart of categories and a separate marker.
var canvas = document.getElementById('bodyFatChart');
ctx = canvas.getContext('2d');
// Destroy previous chart if it exists
if (window.myBodyFatChart) {
window.myBodyFatChart.destroy();
}
window.myBodyFatChart = new Chart(ctx, {
type: 'bar', // Using bar chart for categories
data: {
labels: categoryLabels,
datasets: [{
label: 'Category Threshold (%)',
data: categoryMaxValues,
backgroundColor: categoryColors,
borderColor: '#fff',
borderWidth: 1
}]
},
options: {
responsive: true,
maintainAspectRatio: true, // Adjust aspect ratio as needed
scales: {
y: {
beginAtZero: true,
max: chartMaxY,
title: {
display: true,
text: 'Body Fat Percentage (%)'
}
},
x: {
title: {
display: true,
text: 'Category'
}
}
},
plugins: {
legend: {
display: false // Hiding legend as labels are on X-axis
},
tooltip: {
callbacks: {
label: function(context) {
var label = context.dataset.label || '';
if (label) {
label += ': ';
}
label += context.parsed.y + '%';
return label;
}
}
},
// Add a custom annotation for the user's BF%
annotation: {
annotations: [{
type: 'line',
mode: 'vertical',
scaleID: 'x',
value: context.dataIndex, // This needs to be dynamic based on the category found
borderColor: 'rgb(255, 99, 132)',
borderWidth: 4,
label: {
content: 'Your BF% (' + userBF + '%)',
enabled: true,
position: 'center',
backgroundColor: 'rgba(255, 99, 132, 0.7)',
color: 'white'
}
}]
}
}
}
});
// The annotation plugin needs to be registered. We'll simulate adding it.
// In a real scenario, you'd include the Chart.js annotation plugin.
// Since we are restricted to pure JS/HTML/CSS, we can't dynamically add plugins.
// For this example, we'll draw a manual marker or use a simpler chart type.
// Let's switch to a simpler chart type that doesn't require external plugins.
// A line chart with a marker might be better.
if (window.myBodyFatChart) {
window.myBodyFatChart.destroy();
}
var chartDataObj = {
labels: categoryLabels,
datasets: [{
label: 'Category Upper Limit (%)',
data: categoryMaxValues,
backgroundColor: categoryColors,
borderColor: '#fff',
borderWidth: 1,
type: 'bar' // Make this a bar
}, {
label: 'Your BF%',
data: Array(categoryLabels.length).fill(null).map(function(_, i) {
// Place the marker only at the index corresponding to the user's category
var lowerBound, upperBound;
if (gender === 'male') { lowerBound = maleRanges; upperBound = maleRanges;}
else { lowerBound = femaleRanges; upperBound = femaleRanges;}
var catIndex = -1;
if (userBF <= lowerBound.essential[1]) catIndex = 0;
else if (userBF <= lowerBound.athletes[1]) catIndex = 1;
else if (userBF <= lowerBound.fitness[1]) catIndex = 2;
else if (userBF <= lowerBound.average[1]) catIndex = 3;
else catIndex = 4;
// Return userBF only at the correct index, else null
return (i === catIndex) ? userBF : null;
}),
borderColor: 'rgb(255, 99, 132)',
borderWidth: 4,
type: 'line', // Use line/point marker
pointRadius: 8,
pointHoverRadius: 10,
fill: false,
tension: 0 // Straight line
}]
};
// Adjusting the 'data' for the marker to be more accurate
var markerData = Array(categoryLabels.length).fill(null);
var userCategoryIndex = -1;
if (userBF <= maleRanges.essential[1] && gender === 'male' || userBF <= femaleRanges.essential[1] && gender === 'female') userCategoryIndex = 0;
else if (userBF <= maleRanges.athletes[1] && gender === 'male' || userBF <= femaleRanges.athletes[1] && gender === 'female') userCategoryIndex = 1;
else if (userBF <= maleRanges.fitness[1] && gender === 'male' || userBF <= femaleRanges.fitness[1] && gender === 'female') userCategoryIndex = 2;
else if (userBF <= maleRanges.average[1] && gender === 'male' || userBF <= femaleRanges.average[1] && gender === 'female') userCategoryIndex = 3;
else userCategoryIndex = 4;
if(userCategoryIndex !== -1) {
markerData[userCategoryIndex] = userBF;
}
chartDataObj.datasets[1].data = markerData;
window.myBodyFatChart = new Chart(ctx, {
data: chartDataObj,
options: {
responsive: true,
maintainAspectRatio: false, // Allow aspect ratio adjustment
indexAxis: 'x', // Make it a horizontal bar chart effectively
scales: {
y: {
beginAtZero: true,
max: chartMaxY,
title: {
display: true,
text: 'Body Fat Percentage (%)'
}
},
x: {
title: {
display: true,
text: 'Category'
}
}
},
plugins: {
legend: {
display: true // Show legend for the two datasets
},
tooltip: {
mode: 'index',
intersect: false,
callbacks: {
label: function(tooltipItem) {
var label = tooltipItem.dataset.label || '';
if (label) {
label += ': ';
}
if (tooltipItem.datasetIndex === 0) { // Category Threshold
label += tooltipItem.raw + '%';
} else if (tooltipItem.datasetIndex === 1 && tooltipItem.raw !== null) { // Your BF%
label += tooltipItem.raw + '%';
} else {
return null; // Don't show tooltip for null values
}
return label;
}
}
}
},
// Adding custom element for the marker. This is a bit complex without plugins.
// A simpler approach might be to just use the line chart effectively.
}
});
}
// Initial calculation and chart rendering on load if default values are present
// Or just to set up the chart structure
document.addEventListener('DOMContentLoaded', function() {
// Trigger initial calculation if fields have default values, or setup empty chart
resetForm(); // Reset to clear any pre-filled data and set defaults
updateChart(0, 'male'); // Initialize chart with dummy data
});