What is My Natural Weight Calculator

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What is My Natural Weight Calculator

Understand your body's ideal weight range.

Natural Weight Calculator

Enter your height in centimeters (e.g., 170).
Enter your age in years (e.g., 30).
Male Female Select your biological sex for more accurate calculations.
Sedentary (little to no exercise) Lightly Active (light exercise/sports 1-3 days/week) Moderately Active (moderate exercise/sports 3-5 days/week) Very Active (hard exercise/sports 6-7 days a week) Extra Active (very hard exercise/sports & physical job) Choose the option that best describes your typical physical activity.

Your Natural Weight Range

BMR: —
TDEE: —
Healthy Weight Min: —
Healthy Weight Max: —
Calculations based on Mifflin-St Jeor Equation for BMR, activity multipliers for TDEE, and BMI ranges for healthy weight.

Natural Weight vs. BMI Categories

Underweight Healthy Weight Overweight Obese

Healthy Weight Range by Height

Height (cm) Healthy Weight (kg) – Min Healthy Weight (kg) – Max BMI Range

What is Natural Weight?

Natural weight, often referred to as your "ideal" or "healthy" weight, represents a weight range that is most conducive to your overall health and well-being. It's not a single, fixed number but rather a spectrum that considers various physiological factors unique to your body. Achieving and maintaining a natural weight range can significantly reduce the risk of numerous chronic diseases, improve energy levels, and enhance quality of life. This concept moves beyond simple aesthetics to focus on sustainable health.

The idea of a "natural weight" is rooted in the understanding that each individual's body has an optimal weight it strives to maintain when provided with adequate nutrition and appropriate physical activity. This weight is influenced by genetics, metabolism, body composition (muscle vs. fat), bone density, and even hormonal balance. It's the weight at which your body functions most efficiently, with minimal strain on its systems.

Who Should Use a Natural Weight Calculator?

Anyone interested in understanding their body's optimal weight range can benefit from a natural weight calculator. This includes:

  • Individuals looking to lose weight, gain weight, or maintain their current weight in a healthy manner.
  • People seeking to improve their overall health and reduce the risk of weight-related conditions like heart disease, diabetes, and certain cancers.
  • Athletes and fitness enthusiasts aiming to optimize their body composition for performance.
  • Those curious about their body's natural set point and how it compares to current weight.
  • Healthcare professionals and dietitians using it as a tool to guide patient consultations.

Common Misconceptions About Natural Weight

Several myths surround the concept of natural weight:

  • It's a single magic number: Natural weight is a range, not a precise figure. Genetics and individual physiology create variation.
  • It's purely about appearance: While often linked to aesthetics, natural weight is fundamentally about health and physiological function.
  • It's static: Your natural weight can fluctuate slightly over time due to age, lifestyle changes, and hormonal shifts.
  • It's solely determined by diet: Physical activity, sleep, stress levels, and genetics all play crucial roles.
  • Crash diets achieve natural weight: Extreme dieting often leads to unsustainable weight loss and can disrupt your body's natural weight regulation.

{primary_keyword} Formula and Mathematical Explanation

Calculating your natural weight involves several steps, typically starting with estimating your Basal Metabolic Rate (BMR), then your Total Daily Energy Expenditure (TDEE), and finally using Body Mass Index (BMI) categories to define a healthy weight range for your height. A widely accepted formula for BMR is the Mifflin-St Jeor equation, which is considered more accurate than older formulas like Harris-Benedict for most populations.

Basal Metabolic Rate (BMR) Calculation

BMR is the number of calories your body needs to perform basic life-sustaining functions at rest. The Mifflin-St Jeor equation is:

  • For Men: BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5
  • For Women: BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161

Since our calculator focuses on determining a *healthy weight range* rather than calculating TDEE from a current weight, we will use the height, age, and sex inputs to establish the framework for healthy weight, and then use TDEE as a secondary metric for understanding energy balance.

Total Daily Energy Expenditure (TDEE) Calculation

TDEE is the total number of calories you burn in a day, including BMR and physical activity. It's calculated by multiplying BMR by an activity factor:

  • Sedentary: BMR × 1.2
  • Lightly Active: BMR × 1.375
  • Moderately Active: BMR × 1.55
  • Very Active: BMR × 1.725
  • Extra Active: BMR × 1.9

While TDEE helps understand calorie needs for a *given* weight, our primary goal here is to find the *healthy weight range* for a given height.

Healthy Weight Range using BMI

The most common method to define a healthy weight range for a given height is through the Body Mass Index (BMI). BMI is calculated as:

BMI = weight (kg) / (height (m))^2

The standard BMI categories are:

  • Underweight: < 18.5
  • Healthy Weight: 18.5 – 24.9
  • Overweight: 25 – 29.9
  • Obese: ≥ 30

To find the healthy weight range (BMI 18.5 to 24.9) for a specific height, we rearrange the BMI formula:

Weight (kg) = BMI × (height (m))^2

So, for a given height in meters (height_cm / 100):

  • Minimum Healthy Weight (kg) = 18.5 × (height (m))^2
  • Maximum Healthy Weight (kg) = 24.9 × (height (m))^2

Variables and Formula Explanation

Variable Meaning Unit Typical Range
Height Individual's height cm / m 140 – 200 cm (55 – 79 in)
Age Individual's age Years 18 – 80+
Sex Biological sex (influences BMR constants) Category Male / Female
Activity Level Frequency and intensity of physical activity Category Sedentary to Extra Active
Weight Individual's body mass kg Variable (used for TDEE calculation, target for healthy range)
BMR Basal Metabolic Rate (calories burned at rest) kcal/day ~1200 – 2000+
TDEE Total Daily Energy Expenditure (total calories burned daily) kcal/day ~1500 – 3000+
BMI Body Mass Index (ratio of weight to height squared) kg/m² 18.5 – 24.9 (Healthy Range)

Practical Examples (Real-World Use Cases)

Example 1: A Moderately Active Woman

Inputs:

  • Height: 165 cm
  • Age: 35 years
  • Sex: Female
  • Activity Level: Moderately Active

Calculations:

  • Height in meters: 1.65 m
  • BMR (approx): (10 * W) + (6.25 * 165) – (5 * 35) – 161 = (10 * W) + 1031.25 – 175 – 161 = (10 * W) + 695.25
  • TDEE (approx): BMR * 1.55
  • Healthy Weight Min (BMI 18.5): 18.5 * (1.65)^2 = 18.5 * 2.7225 ≈ 50.37 kg
  • Healthy Weight Max (BMI 24.9): 24.9 * (1.65)^2 = 24.9 * 2.7225 ≈ 67.79 kg

Results Interpretation:

For a 165 cm tall, 35-year-old moderately active woman, the natural or healthy weight range is approximately 50.4 kg to 67.8 kg. Her TDEE will depend on her current weight, guiding her calorie intake for weight management within this healthy range.

Example 2: A Sedentary Young Man

Inputs:

  • Height: 180 cm
  • Age: 22 years
  • Sex: Male
  • Activity Level: Sedentary

Calculations:

  • Height in meters: 1.80 m
  • BMR (approx): (10 * W) + (6.25 * 180) – (5 * 22) + 5 = (10 * W) + 1125 – 110 + 5 = (10 * W) + 1020
  • TDEE (approx): BMR * 1.2
  • Healthy Weight Min (BMI 18.5): 18.5 * (1.80)^2 = 18.5 * 3.24 ≈ 59.94 kg
  • Healthy Weight Max (BMI 24.9): 24.9 * (1.80)^2 = 24.9 * 3.24 ≈ 80.68 kg

Results Interpretation:

For a 180 cm tall, 22-year-old sedentary male, the natural or healthy weight range is approximately 60.0 kg to 80.7 kg. If his current weight falls outside this range, focusing on gradual adjustments to diet and incorporating light physical activity would be beneficial for moving towards his natural weight.

How to Use This Natural Weight Calculator

Using the natural weight calculator is straightforward. Follow these steps to get your personalized results:

  1. Enter Height: Input your height accurately in centimeters (e.g., 175 for 1.75 meters).
  2. Enter Age: Provide your current age in years.
  3. Select Sex: Choose your biological sex (Male or Female) as this affects metabolic calculations.
  4. Select Activity Level: Choose the option that best reflects your daily physical activity from the dropdown menu.
  5. Calculate: Click the "Calculate Natural Weight" button.

The calculator will instantly display:

  • Primary Result: Your estimated healthy weight range in kilograms.
  • Intermediate Values: Your estimated BMR (Basal Metabolic Rate) and TDEE (Total Daily Energy Expenditure) based on a weight within the healthy range, and the calculated minimum and maximum healthy weights.
  • Formula Explanation: A brief overview of the methods used.

Reading Your Results: The primary result shows the weight range (in kg) considered healthy for your height, age, and sex, based on standard BMI classifications. The intermediate values provide context about your metabolic rate and energy needs.

Decision-Making Guidance: Compare your current weight to the calculated healthy range. If you are significantly above or below this range, it suggests a need to adjust your lifestyle. Consult with a healthcare professional or registered dietitian for personalized advice on achieving and maintaining a healthy weight.

Key Factors That Affect Natural Weight Results

While the calculator provides a standardized estimate, several factors can influence your individual natural weight and the interpretation of results:

  1. Genetics: Your genetic makeup plays a significant role in determining your body frame, metabolism, and where your body naturally tends to store fat. Some individuals naturally have a higher or lower set point weight.
  2. Body Composition: BMI and weight calculations don't distinguish between muscle mass and fat mass. A very muscular individual might have a higher weight that falls into the "overweight" BMI category but is perfectly healthy due to a low body fat percentage.
  3. Bone Density and Frame Size: People with larger bone structures naturally weigh more than those with smaller frames, even at the same height and body fat percentage.
  4. Hormonal Balance: Hormones like thyroid hormones, insulin, cortisol, and sex hormones significantly impact metabolism, appetite, and fat distribution, influencing your natural weight.
  5. Age: Metabolism tends to slow down with age, and body composition can change, potentially shifting your natural weight range slightly over time.
  6. Medical Conditions: Certain health conditions (e.g., PCOS, hypothyroidism, Cushing's syndrome) and medications can affect weight regulation and body composition.
  7. Lifestyle Factors: Chronic stress, inadequate sleep, and hydration levels can all influence hormonal balance and metabolism, indirectly affecting your natural weight.
  8. Nutritional Status: Long-term nutritional deficiencies or excesses can impact body composition and metabolic rate.

Frequently Asked Questions (FAQ)

Q1: Is the calculated natural weight range the same for everyone of the same height?

A: The calculator provides a standardized range based on height, age, and sex using BMI. However, individual factors like genetics and body composition mean your personal "ideal" weight might vary slightly within or even just outside this range.

Q2: What if my current weight is very different from the calculated healthy range?

A: If your current weight is significantly outside the calculated range, it's a signal to evaluate your lifestyle. Focus on sustainable changes in diet and exercise. Consulting a healthcare professional is highly recommended for personalized guidance.

Q3: Does muscle weigh more than fat?

A: Muscle is denser than fat, meaning it takes up less space for the same weight. A pound of muscle weighs the same as a pound of fat, but muscle contributes to a lower BMI for the same weight compared to fat.

Q4: How often should I recalculate my natural weight?

A: Your natural weight range is relatively stable, but significant life changes (major weight loss/gain, pregnancy, aging) might warrant a re-evaluation. For most people, checking annually or when lifestyle changes occur is sufficient.

Q5: Can I use this calculator if I'm pregnant or breastfeeding?

A: No, this calculator is not suitable for pregnant or breastfeeding individuals, as their nutritional and weight needs are significantly different and require specialized medical guidance.

Q6: What is the difference between natural weight and set point weight?

A: Natural weight is often used interchangeably with "set point weight," which is the weight range your body tends to defend. It's influenced by genetics and metabolism, and it can be challenging to permanently move outside this range without consistent effort.

Q7: Is BMI a perfect measure of health?

A: BMI is a useful screening tool but not a definitive measure of health. It doesn't account for body composition, muscle mass, or fat distribution. Health is multifaceted and includes factors beyond weight.

Q8: How does activity level affect the healthy weight calculation?

A: Activity level primarily affects TDEE (Total Daily Energy Expenditure), which is crucial for weight management (losing, gaining, or maintaining). The healthy weight *range* itself is determined by height and BMI categories, but your TDEE dictates the calorie intake needed to stay within that range.

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Disclaimer: This calculator and information are for educational purposes only and do not constitute medical advice. Consult with a healthcare professional for personalized health and weight management guidance.

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input.style.borderColor = 'red'; if (helperSpan) helperSpan.style.display = 'none'; return false; } return true; } function calculateNaturalWeight() { var heightCm = document.getElementById('heightCm'); var age = document.getElementById('age'); var sex = document.getElementById('sex'); var activityLevel = document.getElementById('activityLevel'); var heightCmError = document.getElementById('heightCmError'); var ageError = document.getElementById('ageError'); var isValid = true; isValid = validateInput('heightCm', 50, 250, 'heightCmError', 'heightCmHelper') && isValid; isValid = validateInput('age', 1, 120, 'ageError', 'ageHelper') && isValid; if (!isValid) { document.getElementById('primaryResult').textContent = '–'; document.getElementById('bmr').textContent = 'BMR: –'; document.getElementById('tdee').textContent = 'TDEE: –'; document.getElementById('healthyWeightMin').textContent = 'Healthy Weight Min: –'; document.getElementById('healthyWeightMax').textContent = 'Healthy Weight Max: –'; updateChart([], []); // Clear chart return; } var heightM = parseFloat(heightCm.value) / 100; var ageVal = parseInt(age.value); var sexVal = sex.value; var activityLevelVal = activityLevel.value; // Calculate Healthy Weight Range using BMI var bmiMin = 18.5; var bmiMax = 24.9; var healthyWeightMin = bmiMin * Math.pow(heightM, 2); var healthyWeightMax = bmiMax * Math.pow(heightM, 2); // Calculate BMR using Mifflin-St Jeor (requires a weight, let's use the midpoint of the healthy range for TDEE calculation context) var midHealthyWeight = (healthyWeightMin + healthyWeightMax) / 2; var bmr; if (sexVal === 'male') { bmr = (10 * midHealthyWeight) + (6.25 * parseFloat(heightCm.value)) – (5 * ageVal) + 5; } else { // female bmr = (10 * midHealthyWeight) + (6.25 * parseFloat(heightCm.value)) – (5 * ageVal) – 161; } // Calculate TDEE using activity level multiplier var activityMultiplier; switch (activityLevelVal) { case 'sedentary': activityMultiplier = 1.2; break; case 'lightly_active': activityMultiplier = 1.375; break; case 'moderately_active': activityMultiplier = 1.55; break; case 'very_active': activityMultiplier = 1.725; break; case 'extra_active': activityMultiplier = 1.9; break; default: activityMultiplier = 1.2; } var tdee = bmr * activityMultiplier; // Display Results document.getElementById('primaryResult').textContent = healthyWeightMin.toFixed(1) + ' – ' + healthyWeightMax.toFixed(1) + ' kg'; document.getElementById('bmr').textContent = 'BMR: ' + bmr.toFixed(0) + ' kcal/day'; document.getElementById('tdee').textContent = 'TDEE (at healthy weight): ' + tdee.toFixed(0) + ' kcal/day'; document.getElementById('healthyWeightMin').textContent = 'Healthy Weight Min: ' + healthyWeightMin.toFixed(1) + ' kg'; document.getElementById('healthyWeightMax').textContent = 'Healthy Weight Max: ' + healthyWeightMax.toFixed(1) + ' kg'; // Update Table populateWeightTable(heightCm.value); // Update Chart updateChart(healthyWeightMin, healthyWeightMax); } function populateWeightTable(currentHeightCm) { var tableBody = document.getElementById('weightTable').getElementsByTagName('tbody')[0]; tableBody.innerHTML = "; // Clear existing rows var heights = [150, 155, 160, 165, 170, 175, 180, 185, 190, 195, 200]; // Example heights for (var i = 0; i < heights.length; i++) { var heightCm = heights[i]; var heightM = heightCm / 100; var hwMin = 18.5 * Math.pow(heightM, 2); var hwMax = 24.9 * Math.pow(heightM, 2); var row = tableBody.insertRow(); var cellHeight = row.insertCell(0); var cellMinWeight = row.insertCell(1); var cellMaxWeight = row.insertCell(2); var cellBmiRange = row.insertCell(3); cellHeight.textContent = heightCm + ' cm'; cellMinWeight.textContent = hwMin.toFixed(1) + ' kg'; cellMaxWeight.textContent = hwMax.toFixed(1) + ' kg'; cellBmiRange.textContent = '18.5 – 24.9'; // Highlight the row corresponding to the calculator's input height if (heightCm == currentHeightCm) { row.style.backgroundColor = 'rgba(0, 74, 153, 0.1)'; row.style.fontWeight = 'bold'; } } } function updateChart(healthyMin, healthyMax) { var ctx = document.getElementById('bmiChart').getContext('2d'); // Destroy previous chart instance if it exists if (chartInstance) { chartInstance.destroy(); } // Define BMI categories and their corresponding weight ranges for a sample height (e.g., 170cm) // We'll use the calculator's height for dynamic range calculation if available var sampleHeightM = document.getElementById('heightCm') ? parseFloat(document.getElementById('heightCm').value) / 100 : 1.70; var sampleHeightCm = sampleHeightM * 100; var underweightMax = 18.5 * Math.pow(sampleHeightM, 2); var healthyWeightMin = 18.5 * Math.pow(sampleHeightM, 2); var healthyWeightMax = 24.9 * Math.pow(sampleHeightM, 2); var overweightMax = 29.9 * Math.pow(sampleHeightM, 2); // Obese starts at 30 var chartData = { labels: ['Underweight', 'Healthy Weight', 'Overweight', 'Obese'], datasets: [{ label: 'Weight Range (kg) for ' + sampleHeightCm.toFixed(0) + ' cm', data: [ underweightMax, // Max weight for underweight healthyWeightMax – healthyWeightMin, // Width of healthy range overweightMax – healthyWeightMax, // Width of overweight range // For obese, we can't set a fixed max without more context, so we represent it as a range starting from the overweight max // Let's represent it as a conceptual range width, e.g., 20kg for demonstration 20 ], backgroundColor: [ 'rgba(108, 117, 125, 0.7)', // Underweight (Grey) 'rgba(40, 167, 69, 0.7)', // Healthy Weight (Green) 'rgba(255, 193, 7, 0.7)', // Overweight (Yellow) 'rgba(220, 53, 69, 0.7)' // Obese (Red) ], borderColor: [ 'rgba(108, 117, 125, 1)', 'rgba(40, 167, 69, 1)', 'rgba(255, 193, 7, 1)', 'rgba(220, 53, 69, 1)' ], borderWidth: 1 }] }; // Adjusting data for stacked bar chart representation if needed, or keep as is for simple bar chart // For a clearer visual, let's use a stacked bar approach conceptually or adjust labels. // A simpler bar chart showing the *width* of each category is often clearer. // Let's refine the data to show the *upper limit* of each category relative to the start of the healthy range. // Or, better, show the calculated ranges directly. var chartDataRanges = { labels: ['Underweight', 'Healthy Weight', 'Overweight', 'Obese'], datasets: [{ label: 'Weight Range (kg) for ' + sampleHeightCm.toFixed(0) + ' cm', data: [ underweightMax, // Upper limit of underweight healthyWeightMax, // Upper limit of healthy overweightMax, // Upper limit of overweight overweightMax + 20 // Conceptual upper limit for obese (example) ], backgroundColor: [ 'rgba(108, 117, 125, 0.7)', // Underweight 'rgba(40, 167, 69, 0.7)', // Healthy Weight 'rgba(255, 193, 7, 0.7)', // Overweight 'rgba(220, 53, 69, 0.7)' // Obese ], borderColor: [ 'rgba(108, 117, 125, 1)', 'rgba(40, 167, 69, 1)', 'rgba(255, 193, 7, 1)', 'rgba(220, 53, 69, 1)' ], borderWidth: 1 }] }; // Let's use a bar chart where each bar represents the *upper bound* of the category. // This requires careful labeling. A simpler approach might be better. // Alternative: Show the calculated healthy range prominently. var chartDataFocusHealthy = { labels: ['Underweight', 'Healthy Weight', 'Overweight', 'Obese'], datasets: [{ label: 'BMI Category Weight Range (kg) for ' + sampleHeightCm.toFixed(0) + ' cm', data: [ underweightMax, // Max kg for underweight healthyWeightMax – healthyWeightMin, // Width of healthy range overweightMax – healthyWeightMax, // Width of overweight range 20 // Placeholder width for obese range ], backgroundColor: [ 'rgba(108, 117, 125, 0.7)', // Underweight 'rgba(40, 167, 69, 0.7)', // Healthy Weight 'rgba(255, 193, 7, 0.7)', // Overweight 'rgba(220, 53, 69, 0.7)' // Obese ], borderColor: [ 'rgba(108, 117, 125, 1)', 'rgba(40, 167, 69, 1)', 'rgba(255, 193, 7, 1)', 'rgba(220, 53, 69, 1)' ], borderWidth: 1 }] }; // Let's try a different approach: show the calculated healthy range as a highlighted bar. // We need to calculate the ranges for the *current* height. var currentHeightVal = document.getElementById('heightCm') ? parseFloat(document.getElementById('heightCm').value) : 170; var currentHeightM = currentHeightVal / 100; var currentHWMin = 18.5 * Math.pow(currentHeightM, 2); var currentHWMax = 24.9 * Math.pow(currentHeightM, 2); var currentUWMax = 18.5 * Math.pow(currentHeightM, 2); var currentOWMax = 29.9 * Math.pow(currentHeightM, 2); // Data for the chart: representing the upper bounds of each category var chartDataFinal = { labels: ['Underweight', 'Healthy Weight', 'Overweight', 'Obese'], datasets: [{ label: 'Upper Weight Limit (kg) for ' + currentHeightVal.toFixed(0) + ' cm', data: [ currentUWMax, // Upper limit of underweight currentHWMax, // Upper limit of healthy weight currentOWMax, // Upper limit of overweight currentOWMax + 20 // Conceptual upper limit for obese (example) ], backgroundColor: [ 'rgba(108, 117, 125, 0.7)', // Underweight 'rgba(40, 167, 69, 0.7)', // Healthy Weight 'rgba(255, 193, 7, 0.7)', // Overweight 'rgba(220, 53, 69, 0.7)' // Obese ], borderColor: [ 'rgba(108, 117, 125, 1)', 'rgba(40, 167, 69, 1)', 'rgba(255, 193, 7, 1)', 'rgba(220, 53, 69, 1)' ], borderWidth: 1 }] }; // Add a visual indicator for the calculated healthy range chartDataFinal.datasets.push({ label: 'Calculated Healthy Range', data: [ currentHWMin, // Start of healthy range currentHWMax – currentHWMin, // Width of healthy range 0, // No contribution to overweight bar 0 // No contribution to obese bar ], backgroundColor: 'rgba(0, 74, 153, 0.5)', // Primary color, semi-transparent borderColor: 'rgba(0, 74, 153, 1)', borderWidth: 1, type: 'bar', // Specify type if mixing chart types, but here we'll use it as a distinct dataset stack: 'healthyRange' // Use stack if needed, but simpler to just overlay or use separate dataset }); // Let's simplify: A single bar chart showing the *width* of each category is often best. // We'll use the calculated ranges for the current height. var chartDataWidths = { labels: ['Underweight', 'Healthy Weight', 'Overweight', 'Obese'], datasets: [{ label: 'Weight Range Width (kg) for ' + currentHeightVal.toFixed(0) + ' cm', data: [ currentUWMax, // Max weight for underweight currentHWMax – currentHWMin, // Width of healthy range currentOWMax – currentHWMax, // Width of overweight range 20 // Placeholder width for obese range ], backgroundColor: [ 'rgba(108, 117, 125, 0.7)', // Underweight 'rgba(40, 167, 69, 0.7)', // Healthy Weight 'rgba(255, 193, 7, 0.7)', // Overweight 'rgba(220, 53, 69, 0.7)' // Obese ], borderColor: [ 'rgba(108, 117, 125, 1)', 'rgba(40, 167, 69, 1)', 'rgba(255, 193, 7, 1)', 'rgba(220, 53, 69, 1)' ], borderWidth: 1 }] }; // Add a line or marker for the calculated healthy range chartDataWidths.datasets.push({ label: 'Healthy Range Boundaries', data: [currentHWMin, currentHWMax], // Min and Max of healthy range type: 'line', // Use line to mark specific points borderColor: 'rgba(0, 74, 153, 1)', borderWidth: 3, fill: false, pointRadius: 5, pointBackgroundColor: 'rgba(0, 74, 153, 1)', pointBorderColor: 'rgba(255, 255, 255, 1)', order: 1 // Ensure lines are drawn on top }); // Let's use a simpler bar chart showing the upper limits, and add annotations for clarity. // This requires Chart.js annotations plugin, which is not allowed. // So, let's stick to the width-based bar chart and maybe add text labels. // Final attempt: Bar chart showing the *upper limit* of each category. // This is often the clearest way to visualize ranges. var chartDataUpperLimits = { labels: ['Underweight', 'Healthy Weight', 'Overweight', 'Obese'], datasets: [{ label: 'Upper Weight Limit (kg) for ' + currentHeightVal.toFixed(0) + ' cm', data: [ currentUWMax, // Upper limit of underweight currentHWMax, // Upper limit of healthy weight currentOWMax, // Upper limit of overweight currentOWMax + 20 // Conceptual upper limit for obese (example) ], backgroundColor: [ 'rgba(108, 117, 125, 0.7)', // Underweight 'rgba(40, 167, 69, 0.7)', // Healthy Weight 'rgba(255, 193, 7, 0.7)', // Overweight 'rgba(220, 53, 69, 0.7)' // Obese ], borderColor: [ 'rgba(108, 117, 125, 1)', 'rgba(40, 167, 69, 1)', 'rgba(255, 193, 7, 1)', 'rgba(220, 53, 69, 1)' ], borderWidth: 1 }] }; // Add a visual marker for the calculated healthy range boundaries // This is tricky without plugins. Let's use a secondary dataset that's a line chart. chartDataUpperLimits.datasets.push({ label: 'Healthy Range Boundaries', data: [currentHWMin, currentHWMax], // Min and Max of healthy range type: 'line', borderColor: 'rgba(0, 0, 0, 0.8)', // Black line borderWidth: 2, fill: false, pointRadius: 0, // No points, just lines order: 2 // Draw on top }); chartInstance = new Chart(ctx, { type: 'bar', // Base type is bar data: chartDataUpperLimits, options: { responsive: true, maintainAspectRatio: false, scales: { y: { beginAtZero: true, title: { display: true, text: 'Weight (kg)' } } }, plugins: { tooltip: { callbacks: { label: function(context) { var label = context.dataset.label || ''; if (label) { label += ': '; } if (context.parsed.y !== null) { // Check if it's the boundary line dataset if (context.dataset.label === 'Healthy Range Boundaries') { if (context.dataIndex === 0) label += context.parsed.y.toFixed(1) + ' kg (Min)'; if (context.dataIndex === 1) label += context.parsed.y.toFixed(1) + ' kg (Max)'; } else { label += context.parsed.y.toFixed(1) + ' kg'; } } return label; } } }, legend: { display: true, position: 'top', } }, // Custom drawing for the healthy range line might be needed if the line dataset doesn't render as expected // For simplicity, let's rely on the line dataset. } }); } function resetCalculator() { document.getElementById('heightCm').value = '170'; document.getElementById('age').value = '30'; document.getElementById('sex').value = 'male'; document.getElementById('activityLevel').value = 'moderately_active'; // Clear errors and recalculate document.getElementById('heightCmError').style.display = 'none'; document.getElementById('ageError').style.display = 'none'; document.getElementById('heightCm').style.borderColor = '#ccc'; document.getElementById('age').style.borderColor = '#ccc'; calculateNaturalWeight(); } function copyResults() { var primaryResult = document.getElementById('primaryResult').textContent; var bmr = document.getElementById('bmr').textContent; var tdee = document.getElementById('tdee').textContent; var healthyWeightMin = document.getElementById('healthyWeightMin').textContent; var healthyWeightMax = document.getElementById('healthyWeightMax').textContent; var heightCm = document.getElementById('heightCm').value; var age = document.getElementById('age').value; var sex = document.getElementById('sex').value; var activityLevel = document.getElementById('activityLevel').options[document.getElementById('activityLevel').selectedIndex].text; var assumptions = "Assumptions:\n"; assumptions += "- Height: " + heightCm + " cm\n"; assumptions += "- Age: " + age + " years\n"; assumptions += "- Sex: " + sex + "\n"; assumptions += "- Activity Level: " + activityLevel + "\n"; var resultsText = "— Natural Weight Calculator Results —\n\n"; resultsText += "Your Natural Weight Range:\n" + primaryResult + "\n\n"; resultsText += bmr + "\n"; resultsText += tdee + "\n"; resultsText += healthyWeightMin + "\n"; resultsText += healthyWeightMax + "\n\n"; resultsText += assumptions; // Use navigator.clipboard for modern browsers, fallback to execCommand for older ones if (navigator.clipboard && navigator.clipboard.writeText) { navigator.clipboard.writeText(resultsText).then(function() { alert('Results copied to clipboard!'); }).catch(function(err) { console.error('Failed to copy text: ', err); fallbackCopyTextToClipboard(resultsText); }); } else { fallbackCopyTextToClipboard(resultsText); } } function fallbackCopyTextToClipboard(text) { var textArea = document.createElement("textarea"); textArea.value = text; textArea.style.position = "fixed"; // Avoid scrolling to bottom textArea.style.left = "-9999px"; textArea.style.top = "-9999px"; document.body.appendChild(textArea); textArea.focus(); textArea.select(); try { var successful = document.execCommand('copy'); var msg = successful ? 'Results copied to clipboard!' : 'Failed to copy results.'; alert(msg); } catch (err) { console.error('Fallback: Oops, unable to copy', err); alert('Failed to copy results. Please copy manually.'); } document.body.removeChild(textArea); } // Initial calculation and table population on page load window.onload = function() { calculateNaturalWeight(); populateWeightTable(document.getElementById('heightCm').value); // Ensure table is populated on load // Ensure chart is drawn on load var heightCm = document.getElementById('heightCm') ? parseFloat(document.getElementById('heightCm').value) : 170; var heightM = heightCm / 100; var hwMin = 18.5 * Math.pow(heightM, 2); var hwMax = 24.9 * Math.pow(heightM, 2); updateChart(hwMin, hwMax); }; // Add event listeners for real-time updates document.getElementById('heightCm').addEventListener('input', calculateNaturalWeight); document.getElementById('age').addEventListener('input', calculateNaturalWeight); document.getElementById('sex').addEventListener('change', calculateNaturalWeight); document.getElementById('activityLevel').addEventListener('change', calculateNaturalWeight);

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