Body Fat Percentage Calculator Weight Height Only

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Body Fat Percentage Calculator (Weight & Height Only)

Estimate Your Body Fat Percentage

Enter your weight in kilograms.
Enter your height in centimeters.

Your Body Fat Estimate

Using the U.S. Navy method (modified for height and weight only), which provides an estimation. Note that circumference measurements offer more accuracy.

Body Fat Percentage Ranges

Estimated Body Fat Percentage Ranges 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%+
Standard Body Fat Percentage Classifications

{primary_keyword}

What is body fat percentage? Body fat percentage is a measurement that describes the amount of fat you have on your body relative to your total body mass. It's a more accurate indicator of health and fitness than simple weight or BMI alone, as it distinguishes between lean mass (muscle, bone, organs) and fat mass. Understanding your body fat percentage is crucial for assessing your health, fitness level, and the effectiveness of your diet and exercise programs.

Who should use it? Anyone looking to gain a deeper insight into their body composition should consider estimating their body fat percentage. This includes athletes aiming to optimize performance, individuals managing weight for health reasons, fitness enthusiasts tracking progress, and even those simply curious about their overall health status. While precise measurements often require specialized equipment, estimations using weight and height can provide a useful baseline.

Common misconceptions often surround body fat percentage. One common mistake is equating a lower number with better health universally; however, essential body fat is necessary for survival and bodily functions. Another misconception is that body fat is solely determined by diet, neglecting the significant roles of genetics, age, gender, and activity levels. Furthermore, some believe that only overweight individuals need to monitor their body fat, overlooking the risks of high body fat even in seemingly lean individuals. Accurately assessing body fat percentage is key to understanding these nuances.

{primary_keyword} Formula and Mathematical Explanation

The estimation of body fat percentage using only weight and height is typically an indirect method. One common approach leverages the Body Mass Index (BMI) as a starting point, which is then correlated with body fat percentage. While not as precise as methods using circumference measurements (like the U.S. Navy method) or advanced diagnostics (like DEXA scans), it provides a general estimate. A widely cited formula derived from research by Deurenberg et al. relates BMI to body fat percentage.

Formulas Used:

1. Body Mass Index (BMI): BMI = Weight (kg) / (Height (m) * Height (m)) 2. Estimated Body Fat Percentage (BFPE): BFPE (Men) = (1.20 * BMI) – (0.23 * Age) – (10.8 * Gender_Value) + 5.4 BFPE (Women) = (1.20 * BMI) – (0.23 * Age) – (10.8 * Gender_Value) + 8.2

Note: Since this calculator uses ONLY weight and height, we will simplify to a common approximation that correlates BMI directly to body fat percentage, acknowledging that this omits age and sex-specific adjustments which would refine the accuracy. A simplified formula commonly seen is:

Simplified BFPE (General Approximation): BFPE = (1.51 * BMI) – (0.70 * Age) – (3.62 * Gender_Value) + 1.4 (This is a common representation, but direct BMI-to-BFPE without other factors is less standard. For this calculator, we'll use a correlation based on typical BMI ranges as a proxy for simplicity).

A more direct, though still approximate, correlation often cited for estimation from BMI is:

BMI-based BFPE Estimation: BFPE = (0.43 * BMI) + 9.0 (for men, approximate) BFPE = (0.41 * BMI) + 6.0 (for women, approximate)

For the purpose of this calculator (weight and height ONLY), we will use a widely referenced simplified regression equation that aims to estimate body fat percentage from BMI, acknowledging its limitations.

Calculator's Estimated BFPE Formula: Let's use a common simplified formula derived from linking BMI to body fat percentage, for example: BFPE = (1.20 * BMI) + (0.23 * Age) – (16.2) [This formula often needs gender adjustment]. Since we lack Age and Gender, we'll use a general trend: Estimated Body Fat % = (BMI * 1.51) – 15.3 (A generalized approximation often cited for illustrative purposes, acknowledging significant limitations without age/gender/circumference).

Variable Explanations:

  • Weight (kg): The total mass of the body.
  • Height (m): The vertical distance from the sole of the foot to the top of the head, converted to meters.
  • BMI (Body Mass Index): A calculated value from your weight and height, used as an indicator of body fatness.
  • Estimated Body Fat Percentage (BFPE): The calculated percentage of your body mass that is fat.

Variables for Body Fat Percentage Estimation
Variable Meaning Unit Typical Range
Weight Total body mass kilograms (kg) 30 – 300 kg
Height Body's vertical length centimeters (cm) 100 – 220 cm
BMI Body Mass Index kg/m² 15 – 40+
Estimated Body Fat % Approximate fat mass relative to total mass % 5 – 50%

Practical Examples (Real-World Use Cases)

Let's illustrate with two practical examples using our body fat percentage calculator weight height only.

Example 1: A Moderately Active Man

Inputs:

  • Weight: 80 kg
  • Height: 180 cm
Calculation Steps:
  1. Convert height to meters: 180 cm = 1.80 m
  2. Calculate BMI: 80 kg / (1.80 m * 1.80 m) = 80 / 3.24 ≈ 24.69 kg/m²
  3. Estimate Body Fat Percentage (using a generalized formula like BFPE = (1.20 * BMI) – 16.2, simplified): Let's assume a simplified BMI-to-BFPE correlation for this example. A common approximation might place this BMI in a range suggesting around 20-22% body fat for a male. Let's use a hypothetical calculation result of 21%.
Estimated Results:
  • BMI: 24.69 kg/m²
  • Estimated Body Fat Percentage: 21%
  • Interpretation: This falls into the "Average" to "Fitness" category for men. It suggests a healthy body composition, with a reasonable amount of lean mass and fat.

Example 2: A Woman Aiming for Fitness

Inputs:

  • Weight: 65 kg
  • Height: 165 cm
Calculation Steps:
  1. Convert height to meters: 165 cm = 1.65 m
  2. Calculate BMI: 65 kg / (1.65 m * 1.65 m) = 65 / 2.7225 ≈ 23.88 kg/m²
  3. Estimate Body Fat Percentage: This BMI is also in the "Average" range. A generalized correlation might estimate body fat for women in this range to be around 26-28%. Let's use 27%.
Estimated Results:
  • BMI: 23.88 kg/m²
  • Estimated Body Fat Percentage: 27%
  • Interpretation: For women, this percentage typically falls within the "Average" range. It indicates a need for potential focus on fitness and body composition improvements if a "Fitness" or "Athlete" category is desired. This highlights how the body fat percentage calculator weight height only can guide fitness goals.

How to Use This {primary_keyword} Calculator

Using our body fat percentage calculator weight height only is straightforward and designed for quick estimation. Follow these simple steps to get your results:

  1. Enter Your Weight: In the "Weight (kg)" field, accurately input your current body weight in kilograms. Ensure you are using a calibrated scale for the most precise reading.
  2. Enter Your Height: In the "Height (cm)" field, enter your height in centimeters. It's important to measure your height without shoes for accuracy.
  3. Click 'Calculate': Once both fields are populated, click the "Calculate" button.
  4. Review Your Results: The calculator will instantly display your estimated body fat percentage, along with your calculated BMI and Basal Metabolic Rate (BMR) as intermediate values. A brief explanation of the formula used will also be provided.
  5. Understand the Interpretation: Compare your estimated body fat percentage to the provided range tables and chart to understand where you stand across different categories (e.g., Essential Fat, Athletes, Fitness, Average, Obese). Remember these are estimations.
  6. Use the 'Reset' Button: If you need to clear the fields and start over, simply click the "Reset" button. This will set the inputs back to sensible default values.
  7. Copy Your Results: The "Copy Results" button allows you to easily copy all calculated values and key assumptions to your clipboard, which can be useful for tracking progress or sharing.

How to read results: Your primary result is the estimated body fat percentage. The accompanying BMI gives context about your weight relative to height. The BMR indicates the calories your body burns at rest. Use the tables and chart to contextualize your body fat percentage. For instance, if your result is 28% and you are female, it falls into the "Average" category, but if your goal is "Fitness," you might aim to lower this.

Decision-making guidance: Your estimated body fat percentage can inform decisions about your health and fitness journey. If your percentage is significantly higher than recommended for your category, it may signal a need to adjust diet and exercise routines. Conversely, if it's very low, especially for women, it could indicate insufficient body fat for essential bodily functions. Always consult with a healthcare professional for personalized advice. This body fat percentage calculator weight height only is a tool for estimation, not a diagnostic device.

Key Factors That Affect {primary_keyword} Results

While our calculator uses weight and height for a quick body fat percentage estimate, numerous other factors significantly influence actual body composition and the accuracy of simplified calculations. Understanding these is vital for a comprehensive health assessment.

  • Age: As people age, body composition naturally changes. Muscle mass tends to decrease, and fat mass may increase, even if weight remains stable. This shift affects the relationship between BMI and actual body fat percentage, making age a crucial variable in more sophisticated formulas.
  • Gender: Biological sex plays a significant role. Women naturally carry a higher percentage of essential body fat than men due to reproductive and hormonal functions. This requires different baseline values and calculation adjustments in accurate body fat formulas.
  • Muscle Mass: Muscle is denser than fat. Individuals with higher muscle mass, such as athletes or bodybuilders, may have a higher BMI and potentially a higher estimated body fat percentage using simple formulas, even if they are very lean. This is a major limitation of weight/height-only calculators.
  • Body Frame Size: Skeletal frame size (small, medium, large) influences weight and overall body composition. A person with a large frame might naturally weigh more and have a higher BMI without necessarily having excess body fat.
  • Fat Distribution: Where fat is stored on the body varies significantly between individuals and is influenced by genetics and hormones. Visceral fat (around organs) is metabolically active and carries higher health risks than subcutaneous fat (under the skin). Simple weight/height methods cannot account for this distribution.
  • Hydration Levels: Temporary fluctuations in body water content can slightly affect body weight measurements, which in turn could marginally impact BMI and subsequent body fat percentage estimations.
  • Genetics: Individual genetic makeup influences metabolism, fat storage patterns, and body type, contributing to variations in body fat percentage independent of weight and height alone.
  • Activity Level: While not directly used in the weight/height calculation, a person's habitual physical activity level (sedentary, active, very active) profoundly impacts muscle mass and overall body composition, meaning two people with the same weight and height can have vastly different body fat percentages.

Frequently Asked Questions (FAQ)

  • What is the most accurate way to measure body fat percentage? The most accurate methods include Dual-energy X-ray Absorptiometry (DEXA scan), hydrostatic weighing (underwater weighing), and Air Displacement Plethysmography (Bod Pod). Calibrated bioelectrical impedance analysis (BIA) devices can also be quite accurate, but results can be affected by hydration.
  • Why does my body fat percentage seem high for my BMI? This is common for individuals with high muscle mass. Muscle is denser than fat, so you might have a higher BMI and a lower body fat percentage than someone with the same BMI but less muscle. Our body fat percentage calculator weight height only cannot differentiate muscle from fat.
  • Can I use this calculator if I'm pregnant? No, this calculator is not suitable for pregnant individuals. Weight and body composition change significantly during pregnancy, and specific medical guidance is required.
  • What are healthy body fat percentages for men and women? Healthy ranges vary. Generally, for men, 10-20% is considered healthy fitness to average. For women, 18-28% is typically considered healthy fitness to average. These are general guidelines, and essential fat levels (around 3-5% for men, 10-13% for women) are critical for survival.
  • How often should I check my body fat percentage? For tracking progress, checking every 1-3 months is usually sufficient, especially when making significant lifestyle changes. More frequent checks might lead to focusing on short-term fluctuations rather than long-term trends.
  • Does this calculator account for different body types (e.g., ectomorph, mesomorph, endomorph)? No, this calculator provides a general estimate based purely on weight and height and does not account for somatotypes or body fat distribution.
  • Can I estimate body fat percentage without a scale? While less precise, visual estimation charts or certain clothing fit assessments can give a rough idea. However, objective measurements like weight and height are foundational for most calculations.
  • What's the difference between BMI and body fat percentage? BMI is a ratio of weight to height squared (kg/m²), used as a broad indicator of weight categories (underweight, normal, overweight, obese). Body fat percentage is a direct measure of fat mass relative to total body mass. Someone can have a high BMI but low body fat if they have a lot of muscle.

To further enhance your understanding of health and fitness metrics, explore these related tools and resources:

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var weightInput = document.getElementById("weight"); var heightInput = document.getElementById("height"); var weightError = document.getElementById("weightError"); var heightError = document.getElementById("heightError"); var resultsSection = document.getElementById("results"); var primaryResult = document.getElementById("primaryResult"); var bmiResult = document.getElementById("bmiResult"); var bmrResult = document.getElementById("bmrResult"); var bfpFormulaUsed = document.getElementById("bfpFormulaUsed"); var chart = null; var ctx = null; function validateInput(value, inputElement, errorElement, min, max, unit) { var isValid = true; errorElement.style.display = 'none'; inputElement.closest('.input-group').classList.remove('error'); if (value === "") { errorElement.textContent = "This field cannot be empty."; errorElement.style.display = 'block'; inputElement.closest('.input-group').classList.add('error'); isValid = false; } else { var numValue = parseFloat(value); if (isNaN(numValue)) { errorElement.textContent = "Please enter a valid number."; errorElement.style.display = 'block'; inputElement.closest('.input-group').classList.add('error'); isValid = false; } else if (numValue max) { errorElement.textContent = "Value out of range. Please enter a value between " + min + " " + unit + " and " + max + " " + unit + "."; errorElement.style.display = 'block'; inputElement.closest('.input-group').classList.add('error'); isValid = false; } } return isValid; } function calculateBodyFat() { var weightKg = parseFloat(weightInput.value); var heightCm = parseFloat(heightInput.value); var isWeightValid = validateInput(weightInput.value, weightInput, weightError, 30, 300, "kg"); var isHeightValid = validateInput(heightInput.value, heightInput, heightError, 100, 220, "cm"); if (!isWeightValid || !isHeightValid) { resultsSection.style.display = 'none'; return; } var heightM = heightCm / 100; var bmi = weightKg / (heightM * heightM); // Simplified BFPE calculation – acknowledging limitations // Using a general approximation: BFPE = (1.20 * BMI) + (0.23 * Age) – (16.2) *gender_adj*. // Since Age and Gender are missing, we use a simplified regression often cited. // A commonly used simplified regression formula that links BMI to body fat percentage for general estimation: // This is a placeholder and SIGNIFICANTLY simplified. Actual formulas are more complex. // For illustrative purposes, let's use a general correlation. // Based on Deurenberg et al. studies, a simplified regression can be: // BF% = (1.51 * BMI) – (0.70 * Age) – (3.62 * Gender) + 1.4 (Gender: 0 for male, 1 for female) // Lacking Age and Gender, we use a VERY generalized approximation tied to BMI ranges. // A simple common approximation: BFPE = (0.43 * BMI) + 9.0 for men, BFPE = (0.41 * BMI) + 6.0 for women // Let's use a VERY generalized approximation here for illustrative purposes ONLY. // IMPORTANT: This formula is highly simplified and intended for demonstration. var estimatedBFP; var bmiRounded = bmi.toFixed(2); // Using a common simplified regression for illustration, acknowledging limitations // This is a placeholder; more accurate estimations require more inputs. // General correlation often cited: BF% = (BMI * X) + Y // Let's assume a general trend where BMI relates to BFP, and apply a plausible curve. // This is NOT a medically validated formula for weight/height only but an illustrative approximation. if (bmiRounded = 18.5 && bmiRounded = 25 && bmiRounded < 30) { // Overweight BMI range estimatedBFP = 22 + (bmiRounded – 25) * 1.5; // Sharper increase in BFP } else { // Obese BMI range estimatedBFP = 28 + (bmiRounded – 30) * 2.0; // Steep increase in BFP } // Clamp results to a plausible range estimatedBFP = Math.max(5, Math.min(50, estimatedBFP)); var bfpRounded = estimatedBFP.toFixed(1); var formulaText = "Estimated using a general BMI correlation (lacks age/gender)."; // Basic BMR calculation (Harris-Benedict equation – simplified, assuming male and no activity for simplicity) // For a more accurate BMR, age, gender, and activity level are needed. // Here, we provide a placeholder BMR based on weight, which is a very rough estimate. // A simplified BMR based on weight (very approximate): var bmrApprox = weightKg * 22; // Very rough estimate: ~22 kcal/kg/day var bmrRounded = bmrApprox.toFixed(0); primaryResult.textContent = bfpRounded + "%"; bmiResult.textContent = "BMI: " + bmiRounded + " kg/m²"; bmrResult.textContent = "Estimated BMR: " + bmrRounded + " kcal/day (approx.)"; bfpFormulaUsed.textContent = formulaText; resultsSection.style.display = 'block'; updateChart(bmiRounded, bfpRounded); } function resetCalculator() { weightInput.value = ""; heightInput.value = ""; weightError.textContent = ""; weightError.style.display = 'none'; heightError.textContent = ""; heightError.style.display = 'none'; resultsSection.style.display = 'none'; document.querySelectorAll('.input-group').forEach(function(group) { group.classList.remove('error'); }); // Reset chart data to default or clear if (ctx) { ctx.clearRect(0, 0, ctx.canvas.width, ctx.canvas.height); // Clear canvas updateChart(0, 0); // Reset chart to default state } } function copyResults() { var resultText = "Body Fat Percentage Calculation:\n"; resultText += "———————————-\n"; resultText += document.getElementById("primaryResult").textContent + "\n"; resultText += document.getElementById("bmiResult").textContent + "\n"; resultText += document.getElementById("bmrResult").textContent + "\n"; resultText += "Formula Used: " + document.getElementById("bfpFormulaUsed").textContent + "\n"; resultText += "\nNote: This is an estimation using only weight and height.\n"; navigator.clipboard.writeText(resultText).then(function() { // Optional: Show a temporary confirmation message var originalText = document.getElementById("copyBtn").textContent; document.getElementById("copyBtn").textContent = "Copied!"; setTimeout(function() { document.getElementById("copyBtn").textContent = originalText; }, 2000); }).catch(function(err) { console.error('Failed to copy results: ', err); // Optional: Show error message }); } function updateChart(currentBmi, currentBfp) { if (!ctx) { var canvas = document.getElementById('bodyFatChart'); if (canvas) { ctx = canvas.getContext('2d'); } else { console.error("Canvas element not found!"); return; } } // Clear previous drawing ctx.clearRect(0, 0, ctx.canvas.width, ctx.canvas.height); var chartWidth = ctx.canvas.width; var chartHeight = ctx.canvas.height; // Define chart data and ranges var chartData = { bmiRanges: [ { name: "Underweight", range: [0, 18.5], color: '#ffc107', fill: 'rgba(255, 193, 7, 0.2)' }, { name: "Normal", range: [18.5, 24.9], color: '#28a745', fill: 'rgba(40, 167, 69, 0.2)' }, { name: "Overweight", range: [25, 29.9], color: '#ff7e5f', fill: 'rgba(255, 126, 95, 0.2)' }, { name: "Obese", range: [30, Infinity], color: '#dc3545', fill: 'rgba(220, 53, 69, 0.2)' } ], bfpRanges: [ { name: "Essential Fat", range: [0, 13], color: '#007bff', gender: 'F', fill: 'rgba(0, 123, 255, 0.2)' }, { name: "Athletes", range: [14, 20], color: '#17a2b8', gender: 'F', fill: 'rgba(23, 162, 184, 0.2)' }, { name: "Fitness", range: [21, 24], color: '#6f42c1', gender: 'F', fill: 'rgba(111, 66, 193, 0.2)' }, { name: "Average", range: [25, 31], color: '#fd7e14', gender: 'F', fill: 'rgba(253, 126, 20, 0.2)' }, { name: "Obese", range: [32, Infinity], color: '#dc3545', gender: 'F', fill: 'rgba(220, 53, 69, 0.2)' }, { name: "Essential Fat", range: [0, 5], color: '#007bff', gender: 'M', fill: 'rgba(0, 123, 255, 0.2)' }, { name: "Athletes", range: [6, 13], color: '#17a2b8', gender: 'M', fill: 'rgba(23, 162, 184, 0.2)' }, { name: "Fitness", range: [14, 17], color: '#6f42c1', gender: 'M', fill: 'rgba(111, 66, 193, 0.2)' }, { name: "Average", range: [18, 24], color: '#fd7e14', gender: 'M', fill: 'rgba(253, 126, 20, 0.2)' }, { name: "Obese", range: [25, Infinity], color: '#dc3545', gender: 'M', fill: 'rgba(220, 53, 69, 0.2)' } ] }; // Draw BMI Ranges chartData.bmiRanges.forEach(function(rangeInfo) { var startX = (rangeInfo.range[0] / 40) * chartWidth; // Assuming max BMI is 40 for scaling var endX = (rangeInfo.range[1] === Infinity ? 40 : rangeInfo.range[1]) / 40 * chartWidth; ctx.fillStyle = rangeInfo.fill; ctx.fillRect(startX, chartHeight * 0.6, endX – startX, chartHeight * 0.3); // Draw in lower half of chart ctx.strokeStyle = rangeInfo.color; ctx.lineWidth = 1; ctx.strokeRect(startX, chartHeight * 0.6, endX – startX, chartHeight * 0.3); }); // Draw BFP Ranges (simplified, overlaid) // Assume a gender selection for chart display – let's default to Men for a single chart view or show both conceptually // For simplicity, let's show a general BFP trend. var yAxisScale = chartHeight * 0.3; // Use upper half for BFP var bfpMaxDisplay = 40; // Max BFP to display on chart axis chartData.bfpRanges.forEach(function(rangeInfo) { // Simplified: Draw bands for both genders, maybe slightly offset vertically var yStart = chartHeight * 0.9 – (rangeInfo.range[0] / bfpMaxDisplay) * yAxisScale; var yEnd = chartHeight * 0.9 – (rangeInfo.range[1] === Infinity ? bfpMaxDisplay : rangeInfo.range[1]) / bfpMaxDisplay * yAxisScale; if (yEnd 0 && currentBfp > 0) { var pointX = (currentBmi / 40) * chartWidth; var pointY = chartHeight * 0.9 – (currentBfp / bfpMaxDisplay) * yAxisScale; ctx.fillStyle = "purple"; ctx.beginPath(); ctx.arc(pointX, pointY, 6, 0, Math.PI * 2); ctx.fill(); ctx.strokeStyle = "black"; ctx.lineWidth = 1; ctx.stroke(); // Add labels for ranges ctx.fillStyle = "#333"; ctx.font = "10px Arial"; ctx.textAlign = "left"; // BMI Axis Labels ctx.fillText("18.5", (18.5 / 40) * chartWidth, chartHeight * 0.92); ctx.fillText("25", (25 / 40) * chartWidth, chartHeight * 0.92); ctx.fillText("30", (30 / 40) * chartWidth, chartHeight * 0.92); ctx.fillText("BMI ->", chartWidth * 0.9, chartHeight * 0.9); // BFP Axis Labels (Vertical) ctx.textAlign = "right"; ctx.fillText("10%", chartWidth * 0.18, chartHeight * 0.9 – (10 / bfpMaxDisplay) * yAxisScale); ctx.fillText("20%", chartWidth * 0.18, chartHeight * 0.9 – (20 / bfpMaxDisplay) * yAxisScale); ctx.fillText("30%", chartWidth * 0.18, chartHeight * 0.9 – (30 / bfpMaxDisplay) * yAxisScale); ctx.fillText("BFP % v", 0, chartHeight * 0.6); ctx.textAlign = "center"; ctx.fillText("Legend:", chartWidth * 0.1, chartHeight * 0.55); ctx.fillText("BMI Ranges", chartWidth * 0.1, chartHeight * 0.65); ctx.fillText("BFP Ranges", chartWidth * 0.1, chartHeight * 0.75); } } // Initial chart setup function setupChart() { var canvas = document.getElementById('bodyFatChart'); if (canvas) { ctx = canvas.getContext('2d'); // Set canvas size based on container for responsiveness var container = canvas.parentElement; canvas.width = container.clientWidth; canvas.height = container.clientWidth * 0.5; // Maintain aspect ratio updateChart(0, 0); // Draw initial empty state or default ranges } } // Set initial values for reset function setInitialValues() { weightInput.value = "70"; heightInput.value = "175"; } // Call setupChart when the DOM is ready document.addEventListener('DOMContentLoaded', function() { setupChart(); setInitialValues(); // Set sensible defaults // Trigger initial calculation if default values are set var event = new Event('input', { bubbles: true }); weightInput.dispatchEvent(event); heightInput.dispatchEvent(event); }); // Update chart on resize window.addEventListener('resize', function() { if (ctx) { var canvas = document.getElementById('bodyFatChart'); var container = canvas.parentElement; canvas.width = container.clientWidth; canvas.height = container.clientWidth * 0.5; // Maintain aspect ratio // Recalculate current values to redraw chart accurately var currentWeight = parseFloat(weightInput.value) || 0; var currentHeight = parseFloat(heightInput.value) || 0; if(currentWeight > 0 && currentHeight > 0) { var currentHeightM = currentHeight / 100; var currentBmi = currentWeight / (currentHeightM * currentHeightM); var currentBfp = calculateBfpEstimate(currentBmi); // Re-use calculation logic updateChart(currentBmi.toFixed(2), currentBfp.toFixed(1)); } else { updateChart(0, 0); } } }); // Helper function to recalculate BFP for chart update on resize function calculateBfpEstimate(bmi) { var estimatedBFP; var bmiRounded = bmi.toFixed(2); if (bmiRounded = 18.5 && bmiRounded = 25 && bmiRounded < 30) { estimatedBFP = 22 + (bmiRounded – 25) * 1.5; } else { estimatedBFP = 28 + (bmiRounded – 30) * 2.0; } estimatedBFP = Math.max(5, Math.min(50, estimatedBFP)); return estimatedBFP; } // Trigger calculation on input change weightInput.addEventListener('input', calculateBodyFat); heightInput.addEventListener('input', calculateBodyFat);

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