Determine your ideal or target body weight based on your specific metrics.
Weight Calculation Tool
Enter height in centimeters (e.g., 175).
Enter your current body fat percentage (e.g., 20).
Enter your desired body fat percentage (e.g., 15).
Your Calculated Weight Results
—
Lean Body Mass (LBM)
—
Fat Mass
—
Target Weight (at target BF%)
—
Formula Used:
Lean Body Mass (LBM) = Current Weight * (1 – (Body Fat % / 100))
Fat Mass = Current Weight – LBM
Target Weight = LBM / (1 – (Target Body Fat % / 100))
Comparison of Current Fat Mass, Lean Body Mass, and Target Weight
Metric
Value
Unit
Current Weight
—
kg
Height
—
cm
Current Body Fat %
—
%
Lean Body Mass (LBM)
—
kg
Fat Mass
—
kg
Target Body Fat %
—
%
Target Weight
—
kg
Key metrics for weight calculation and target setting.
Understanding Calculated Weight and Body Composition
What is Calculated Weight?
Calculated weight refers to a projected or target body weight determined by specific physiological metrics, most commonly height, lean body mass (LBM), and body fat percentage. Unlike a simple scale reading, it provides a more nuanced understanding of body composition. It helps individuals understand how much of their total weight is composed of essential lean mass (muscles, bones, organs) versus non-essential fat mass. This is crucial for health assessments beyond just total mass.
Who should use it: Anyone focused on improving their body composition, athletes aiming for optimal performance, individuals undertaking weight management programs, and those seeking a deeper understanding of their health metrics beyond a simple BMI. It's particularly relevant for those who may have a high amount of muscle mass, which can skew simple weight-to-height ratios like BMI.
Common misconceptions: A common misconception is that "calculated weight" is just another name for a "healthy weight" range derived solely from height. While related, calculated weight often incorporates body fat percentage, acknowledging that muscle is denser than fat and can lead to a higher total weight without necessarily indicating poor health. Another misconception is that it's a static number; it's a dynamic target that changes with fitness and dietary goals.
Calculated Weight Formula and Mathematical Explanation
The core of calculated weight revolves around understanding and manipulating the components of your total body mass: lean body mass (LBM) and fat mass. The goal is often to maintain or increase LBM while reducing fat mass to reach a target body composition.
The primary formulas involved are:
Lean Body Mass (LBM) Calculation: LBM is everything in your body that isn't fat. This includes muscle, bone, water, organs, and connective tissues.
Fat Mass Calculation: This is the portion of your total weight that is fat.
Target Weight Calculation: This projects what your total weight should be if you achieve a desired body fat percentage, assuming your LBM remains constant.
The Formulas in Detail:
Let's define our variables:
Variable
Meaning
Unit
Typical Range
H
Height
cm
140 – 200+
BF%
Body Fat Percentage
%
5 – 40+
TBF%
Target Body Fat Percentage
%
5 – 30
CW
Current Weight
kg
30 – 200+
LBM
Lean Body Mass
kg
Calculated
FM
Fat Mass
kg
Calculated
TW
Target Weight
kg
Calculated
Variables used in calculated weight computations.
Step-by-Step Calculation Derivation:
To calculate your target weight, we first need to determine your current Lean Body Mass (LBM).
1. Calculate Fat Mass (FM):
The total body weight is composed of Lean Body Mass and Fat Mass. To find Fat Mass, we use your Current Weight (CW) and your current Body Fat Percentage (BF%). FM = CW * (BF% / 100)
2. Calculate Lean Body Mass (LBM):
Subtract the Fat Mass from your Current Weight. LBM = CW - FM
Alternatively, if you know your BF%, you can calculate LBM directly: LBM = CW * (1 - (BF% / 100))
3. Calculate Target Weight (TW):
This is the most crucial step for setting a goal. We assume your LBM will remain constant (or you aim to maintain it) and want to find the total weight (TW) that corresponds to your Target Body Fat Percentage (TBF%). The LBM will represent a larger proportion of your new total weight.
The LBM, as a fraction of the total weight, will be (1 - (TBF% / 100)). Therefore: TW * (1 - (TBF% / 100)) = LBM
Rearranging to solve for TW: TW = LBM / (1 - (TBF% / 100))
The calculator above uses these formulas. It requires your height, current body fat percentage, and target body fat percentage. Note that current weight is inferred or calculated based on these inputs and often provided by a separate input field or assumed for demonstration.
Practical Examples (Real-World Use Cases)
Understanding calculated weight is vital for effective health and fitness journeys. Here are a couple of scenarios:
Example 1: The Bodybuilder Aiming for Definition
Scenario: Alex is a bodybuilder who is 180 cm tall and weighs 90 kg. His current body fat percentage is 18%. He wants to reduce his body fat to 10% while maintaining his muscle mass to achieve a leaner physique.
Inputs:
Height: 180 cm
Current Weight: 90 kg
Current Body Fat %: 18%
Target Body Fat %: 10%
Calculations:
Fat Mass = 90 kg * (18 / 100) = 16.2 kg
Lean Body Mass (LBM) = 90 kg – 16.2 kg = 73.8 kg
Target Weight = 73.8 kg / (1 – (10 / 100)) = 73.8 kg / 0.90 = 82 kg
Interpretation: Alex needs to lose approximately 8 kg (90 kg – 82 kg) of fat mass to reach his goal of 10% body fat. His target weight is 82 kg, and his lean body mass of 73.8 kg is preserved. This shows him that his goal weight isn't simply a low number, but a composition goal.
Example 2: The Sedentary Individual Improving Health
Scenario: Ben is 170 cm tall and weighs 85 kg. He has a body fat percentage of 30% and wants to improve his health by reducing it to 20%. He doesn't focus heavily on muscle gain but wants to lose fat.
Inputs:
Height: 170 cm
Current Weight: 85 kg
Current Body Fat %: 30%
Target Body Fat %: 20%
Calculations:
Fat Mass = 85 kg * (30 / 100) = 25.5 kg
Lean Body Mass (LBM) = 85 kg – 25.5 kg = 59.5 kg
Target Weight = 59.5 kg / (1 – (20 / 100)) = 59.5 kg / 0.80 = 74.375 kg
Interpretation: Ben needs to lose approximately 10.6 kg (85 kg – 74.375 kg) of primarily fat mass. His target weight goal is around 74.4 kg, maintaining his LBM of 59.5 kg. This provides a clear, achievable target that focuses on fat loss rather than just weight reduction.
How to Use This Calculated Weight Calculator
Using our online calculator is straightforward and designed to give you actionable insights quickly.
Input Your Metrics:
Height: Enter your height in centimeters (e.g., 175).
Current Body Fat Percentage (%): Enter your current body fat percentage. This can be measured using various methods like bioelectrical impedance analysis (BIA) scales, calipers, or DEXA scans.
Target Body Fat Percentage (%): Enter the body fat percentage you aim to achieve.
Press Calculate: Click the "Calculate" button. The calculator will process your inputs using the established formulas.
Review Your Results:
Primary Result (Target Weight): This is prominently displayed, showing your projected weight at your target body fat percentage.
Intermediate Values: You'll see your calculated Lean Body Mass (LBM) and Fat Mass. LBM is a crucial indicator of your metabolically active tissue, while Fat Mass shows how much excess weight needs to be addressed.
Formula Explanation: A brief explanation of the underlying calculations is provided for transparency.
Table View: A summary table lists all key metrics for easy reference.
Chart: A visual representation compares your current composition (LBM, Fat Mass) with your target weight.
Decision-Making Guidance:
Target Weight: Use this as a realistic goal. Remember, it's about composition, not just a number on the scale.
LBM vs. Fat Mass: Focus on strategies to increase or maintain LBM (e.g., strength training, adequate protein intake) and decrease Fat Mass (e.g., calorie deficit, cardiovascular exercise).
Adjust Goals: If the target weight seems too aggressive or requires unsustainable effort, consider adjusting your target body fat percentage or timeframe. Consult with a healthcare professional or certified trainer for personalized advice.
Copy Results: Use the "Copy Results" button to save or share your calculated data easily.
Reset: Click "Reset" to clear all fields and start fresh.
Key Factors That Affect Calculated Weight Results
While the formulas provide a mathematical framework, several real-world factors influence the accuracy and applicability of calculated weight results:
Accuracy of Body Fat Measurement: This is paramount. Home scales and even some professional methods can have significant margins of error. Inaccurate BF% input directly leads to inaccurate LBM and target weight calculations. Consistent measurement methods are key.
Muscle Mass Variability: The calculation assumes LBM remains constant. However, intense training can increase LBM, and very aggressive dieting can lead to LBM loss. Your actual target weight might shift if your LBM changes significantly.
Hydration Levels: Body weight fluctuates significantly with hydration. Dehydration can make you appear lighter but doesn't change your LBM or fat mass. Conversely, water retention can temporarily increase weight.
Bone Density and Frame Size: While not directly in the calculation, bone structure and density contribute to overall weight. Individuals with denser bones or larger frames might naturally weigh more than someone of the same height and body fat percentage but with a smaller frame.
Hormonal Factors: Hormonal imbalances or changes (e.g., during menopause, thyroid issues) can affect body composition, influencing fat distribution and water retention, indirectly impacting perceived weight goals.
Age: Metabolism tends to slow with age, and body composition can change. Muscle mass may decrease, and fat mass may increase if lifestyle habits aren't adjusted. Target body fat percentages may also need realistic adjustment based on age.
Dietary Intake: Calorie intake and macronutrient balance (protein, carbs, fats) directly impact muscle gain/loss and fat loss, influencing how achievable your target weight is and how quickly you can get there.
Exercise Regimen: The type, frequency, and intensity of exercise play a huge role. Strength training is crucial for preserving/building LBM, while cardio helps burn calories and fat.
Frequently Asked Questions (FAQ)
Q1: What is the difference between calculated weight and BMI?
BMI (Body Mass Index) is a simple ratio of weight to height squared (kg/m²). It's a screening tool but doesn't distinguish between muscle and fat. Calculated weight, especially when using body fat percentage, provides a more accurate picture of body composition, acknowledging that muscle is denser and heavier than fat.
Q2: Is a lower body fat percentage always better?
Not necessarily. While lower body fat is generally associated with better health, extremely low percentages can be unhealthy, particularly for women (affecting hormones) and athletes (impacting performance and recovery). Finding a healthy, sustainable range is key.
Q3: Can my Lean Body Mass change?
Yes. Through consistent strength training and proper nutrition, you can increase your LBM. Conversely, severe calorie restriction without adequate protein or without strength training can lead to LBM loss.
Q4: How often should I measure my body fat percentage?
For tracking progress, measuring every 2-4 weeks is often recommended. Avoid daily measurements, as fluctuations due to hydration and other factors can be misleading. Use the same method and ideally the same device each time.
Q5: My target weight seems very low. What should I do?
This can happen if your current body fat percentage is very high, or your target is very low. Re-evaluate your target body fat percentage for realism. Perhaps a slightly higher BF% is a more achievable and sustainable goal for you. Consult a professional for guidance.
Q6: Do I need my current weight to use this calculator?
While the calculator primarily uses height and body fat percentages, knowing your current weight is essential for understanding your starting point and the magnitude of change needed. Some versions of the calculator might ask for current weight as an input to directly calculate LBM and Fat Mass.
Q7: Can this calculator be used for children?
This specific calculator is designed for adults. Body composition calculations for children require different formulas and considerations due to ongoing growth and development. Consult with a pediatrician or pediatric nutritionist.
Q8: What if I have a very muscular build?
If you have a very muscular build, your weight might be higher than a standard BMI chart suggests. This calculator, by considering body fat percentage, is more suitable as it focuses on the ratio of fat to lean mass rather than just total weight. Your "calculated weight" might reflect a healthy, muscular physique.
Macronutrient Calculator Calculate your ideal daily intake of protein, carbohydrates, and fats for your fitness goals.
Healthy Weight Calculator Find a healthy weight range based on your height and gender using standard formulas.
// Function to validate input
function validateInput(id, errorId, min, max, message) {
var inputElement = document.getElementById(id);
var errorElement = document.getElementById(errorId);
var value = parseFloat(inputElement.value);
errorElement.textContent = "; // Clear previous error
inputElement.parentNode.classList.remove('input-error');
if (isNaN(value)) {
// Allow empty input, but error if user tries to calculate with it
return false;
}
if (value max) {
errorElement.textContent = message + ' cannot be greater than ' + max + '.';
inputElement.parentNode.classList.add('input-error');
return false;
}
return true;
}
// Main calculation function
function calculateWeight() {
var heightInput = document.getElementById('heightInput');
var bodyFatPercentageInput = document.getElementById('bodyFatPercentage');
var targetBodyFatPercentageInput = document.getElementById('targetBodyFatPercentage');
var heightError = document.getElementById('heightError');
var bodyFatError = document.getElementById('bodyFatError');
var targetBodyFatError = document.getElementById('targetBodyFatError');
var resultsDiv = document.getElementById('results');
var mainResult = document.getElementById('mainResult');
var leanBodyMassSpan = document.getElementById('leanBodyMass');
var fatMassSpan = document.getElementById('fatMass');
var targetWeightSpan = document.getElementById('targetWeight');
var tableCurrentWeight = document.getElementById('tableCurrentWeight');
var tableHeight = document.getElementById('tableHeight');
var tableCurrentBF = document.getElementById('tableCurrentBF');
var tableLBM = document.getElementById('tableLBM');
var tableFatMass = document.getElementById('tableFatMass');
var tableTargetBF = document.getElementById('tableTargetBF');
var tableTargetWeight = document.getElementById('tableTargetWeight');
// — Input Validation —
var heightValid = validateInput('heightInput', 'heightError', 100, 300, 'Height'); // Assuming height in cm, reasonable range
var bodyFatValid = validateInput('bodyFatPercentage', 'bodyFatError', 1, 70, 'Body Fat Percentage');
var targetBodyFatValid = validateInput('targetBodyFatPercentage', 'targetBodyFatError', 1, 50, 'Target Body Fat Percentage');
// Additional validation: Target BF% should generally be lower than current BF% for reduction goals
var currentBF = parseFloat(bodyFatPercentageInput.value);
var targetBF = parseFloat(targetBodyFatPercentageInput.value);
if (!isNaN(currentBF) && !isNaN(targetBF) && targetBF >= currentBF) {
targetBodyFatError.textContent = 'Target Body Fat Percentage should be lower than current.';
targetBodyFatPercentageInput.parentNode.classList.add('input-error');
targetBodyFatValid = false;
} else if (!isNaN(currentBF) && !isNaN(targetBF) && targetBF < currentBF){
targetBodyFatPercentageInput.parentNode.classList.remove('input-error');
}
// Need current weight to calculate LBM and Fat Mass accurately for display.
// If not provided, we can assume it based on height and a typical BF%, but it's less precise.
// For this setup, let's add current weight as an input for better accuracy.
var currentWeightInput = document.getElementById('currentWeightInput'); // Assuming this element will be added
if (!currentWeightInput) {
// If currentWeightInput doesn't exist, we need to add it or make assumptions.
// For now, let's make a placeholder assumption if needed, but ideally, it should be an input.
// Let's add it for now.
var existingCurrentWeightInput = document.querySelector('input[id="currentWeightInput"]');
if (!existingCurrentWeightInput) {
var newLabel = document.createElement('label');
newLabel.setAttribute('for', 'currentWeightInput');
newLabel.textContent = 'Current Weight';
var newHelper = document.createElement('div');
newHelper.classList.add('helper-text');
newHelper.textContent = 'Enter your current weight in kilograms (e.g., 85).';
var newError = document.createElement('div');
newError.classList.add('error-message');
newError.setAttribute('id', 'currentWeightError');
var currentWeightGroup = document.createElement('div');
currentWeightGroup.classList.add('input-group');
currentWeightGroup.appendChild(newLabel);
var newWeightInput = document.createElement('input');
newWeightInput.setAttribute('type', 'number');
newWeightInput.setAttribute('id', 'currentWeightInput');
newWeightInput.setAttribute('placeholder', 'Enter current weight');
currentWeightGroup.appendChild(newWeightInput);
currentWeightGroup.appendChild(newHelper);
currentWeightGroup.appendChild(newError);
// Insert it after the target body fat input
targetBodyFatPercentageInput.parentNode.parentNode.insertBefore(currentWeightGroup, targetBodyFatPercentageInput.parentNode.nextSibling);
currentWeightInput = newWeightInput; // Assign the newly created element
}
}
var currentWeightValid = validateInput('currentWeightInput', 'currentWeightError', 30, 500, 'Current Weight'); // Reasonable range for humans
// If any validation fails, stop execution
if (!heightValid || !bodyFatValid || !targetBodyFatValid || !currentWeightValid) {
resultsDiv.style.display = 'none';
return;
}
// — Calculations —
var height = parseFloat(heightInput.value);
var currentBF = parseFloat(bodyFatPercentageInput.value);
var targetBF = parseFloat(targetBodyFatPercentageInput.value);
var currentWeight = parseFloat(currentWeightInput.value); // Use current weight input
var fatMass = currentWeight * (currentBF / 100);
var leanBodyMass = currentWeight – fatMass;
// Alternative LBM calculation: var leanBodyMass = currentWeight * (1 – (currentBF / 100));
var targetWeight = leanBodyMass / (1 – (targetBF / 100));
// Rounding for display
var roundedFatMass = fatMass.toFixed(2);
var roundedLeanBodyMass = leanBodyMass.toFixed(2);
var roundedTargetWeight = targetWeight.toFixed(2);
// — Display Results —
mainResult.textContent = roundedTargetWeight + ' kg';
leanBodyMassSpan.textContent = roundedLeanBodyMass + ' kg';
fatMassSpan.textContent = roundedFatMass + ' kg';
targetWeightSpan.textContent = roundedTargetWeight + ' kg';
// Update Table
tableCurrentWeight.textContent = currentWeight.toFixed(2);
tableHeight.textContent = height.toFixed(0);
tableCurrentBF.textContent = currentBF.toFixed(1);
tableLBM.textContent = roundedLeanBodyMass;
tableFatMass.textContent = roundedFatMass;
tableTargetBF.textContent = targetBF.toFixed(1);
tableTargetWeight.textContent = roundedTargetWeight;
resultsDiv.style.display = 'block';
// — Update Chart —
updateChart(roundedLeanBodyMass, roundedFatMass, roundedTargetWeight);
}
// Function to reset calculator
function resetCalculator() {
document.getElementById('heightInput').value = '';
document.getElementById('bodyFatPercentage').value = '';
document.getElementById('targetBodyFatPercentage').value = '';
document.getElementById('currentWeightInput').value = ''; // Reset the added current weight input
document.getElementById('heightError').textContent = '';
document.getElementById('bodyFatError').textContent = '';
document.getElementById('targetBodyFatError').textContent = '';
document.getElementById('currentWeightError').textContent = ''; // Reset error for current weight
document.getElementById('results').style.display = 'none';
document.getElementById('mainResult').textContent = '–';
document.getElementById('leanBodyMass').textContent = '–';
document.getElementById('fatMass').textContent = '–';
document.getElementById('targetWeight').textContent = '–';
// Reset table
document.getElementById('tableCurrentWeight').textContent = '–';
document.getElementById('tableHeight').textContent = '–';
document.getElementById('tableCurrentBF').textContent = '–';
document.getElementById('tableLBM').textContent = '–';
document.getElementById('tableFatMass').textContent = '–';
document.getElementById('tableTargetBF').textContent = '–';
document.getElementById('tableTargetWeight').textContent = '–';
// Clear chart
var canvas = document.getElementById('weightChart');
var ctx = canvas.getContext('2d');
ctx.clearRect(0, 0, canvas.width, canvas.height);
// Remove error classes
document.getElementById('heightInput').parentNode.classList.remove('input-error');
document.getElementById('bodyFatPercentage').parentNode.classList.remove('input-error');
document.getElementById('targetBodyFatPercentage').parentNode.classList.remove('input-error');
document.getElementById('currentWeightInput').parentNode.classList.remove('input-error');
}
// Function to copy results
function copyResults() {
var mainResult = document.getElementById('mainResult').textContent;
var leanBodyMass = document.getElementById('leanBodyMass').textContent;
var fatMass = document.getElementById('fatMass').textContent;
var targetWeight = document.getElementById('targetWeight').textContent;
var heightValue = document.getElementById('heightInput').value || '–';
var currentBFValue = document.getElementById('bodyFatPercentage').value || '–';
var targetBFValue = document.getElementById('targetBodyFatPercentage').value || '–';
var currentWeightValue = document.getElementById('currentWeightInput') ? document.getElementById('currentWeightInput').value : '–';
var resultsText = "Calculated Weight Results:\n\n" +
"Target Weight: " + mainResult + "\n" +
"Lean Body Mass (LBM): " + leanBodyMass + "\n" +
"Fat Mass: " + fatMass + "\n" +
"\nKey Assumptions:\n" +
"Height: " + heightValue + " cm\n" +
"Current Weight: " + currentWeightValue + " kg\n" +
"Current Body Fat %: " + currentBFValue + " %\n" +
"Target Body Fat %: " + targetBFValue + " %\n";
// Use a temporary textarea to copy
var textArea = document.createElement("textarea");
textArea.value = resultsText;
textArea.style.position = "fixed";
textArea.style.left = "-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); // Simple feedback
} catch (err) {
alert('Oops, unable to copy');
}
document.body.removeChild(textArea);
}
// Charting functionality
var weightChartInstance = null; // To store chart instance
function updateChart(lbm, fatMass, targetWeight) {
var canvas = document.getElementById('weightChart');
var ctx = canvas.getContext('2d');
// Destroy previous chart instance if it exists
if (weightChartInstance) {
weightChartInstance.destroy();
}
// Prepare data – convert to numbers for charting
var numericalLBM = parseFloat(lbm);
var numericalFatMass = parseFloat(fatMass);
var numericalTargetWeight = parseFloat(targetWeight);
var currentWeight = parseFloat(document.getElementById('currentWeightInput').value || '0');
// Handle cases where targetWeight might be less than LBM if target BF% is 0 or negative (though validation should prevent this)
// Ensure the chart scale is reasonable. Max value should accommodate current weight and target weight.
var maxValue = Math.max(currentWeight, numericalLBM + numericalFatMass, numericalTargetWeight) * 1.1; // Add 10% buffer
weightChartInstance = new Chart(ctx, {
type: 'bar',
data: {
labels: ['Current Composition', 'Target Weight'],
datasets: [{
label: 'Lean Body Mass (kg)',
data: [numericalLBM, numericalLBM], // LBM applies to current, and is base for target
backgroundColor: 'rgba(0, 74, 153, 0.6)', // Primary blue
borderColor: 'rgba(0, 74, 153, 1)',
borderWidth: 1
}, {
label: 'Fat Mass (kg)',
data: [numericalFatMass, 0], // Fat mass is part of current, not target
backgroundColor: 'rgba(255, 99, 132, 0.6)', // Reddish for fat
borderColor: 'rgba(255, 99, 132, 1)',
borderWidth: 1
}, {
label: 'Target Total Weight (kg)',
data: [0, numericalTargetWeight], // Target weight is the total goal
backgroundColor: 'rgba(40, 167, 69, 0.6)', // Success green
borderColor: 'rgba(40, 167, 69, 1)',
borderWidth: 1
}]
},
options: {
responsive: true,
maintainAspectRatio: false,
scales: {
y: {
beginAtZero: true,
title: {
display: true,
text: 'Weight (kg)'
},
max: maxValue
},
x: {
title: {
display: true,
text: 'Category'
}
}
},
plugins: {
title: {
display: true,
text: 'Current Body Composition vs. Target Weight'
},
legend: {
position: 'top',
}
}
}
});
}
// Initial setup: Add current weight input if it doesn't exist, then update chart
document.addEventListener('DOMContentLoaded', function() {
var currentWeightInput = document.querySelector('input[id="currentWeightInput"]');
if (!currentWeightInput) {
var newLabel = document.createElement('label');
newLabel.setAttribute('for', 'currentWeightInput');
newLabel.textContent = 'Current Weight';
var newHelper = document.createElement('div');
newHelper.classList.add('helper-text');
newHelper.textContent = 'Enter your current weight in kilograms (e.g., 85).';
var newError = document.createElement('div');
newError.classList.add('error-message');
newError.setAttribute('id', 'currentWeightError');
var currentWeightGroup = document.createElement('div');
currentWeightGroup.classList.add('input-group');
currentWeightGroup.appendChild(newLabel);
var newWeightInput = document.createElement('input');
newWeightInput.setAttribute('type', 'number');
newWeightInput.setAttribute('id', 'currentWeightInput');
newWeightInput.setAttribute('placeholder', 'Enter current weight');
currentWeightGroup.appendChild(newWeightInput);
currentWeightGroup.appendChild(newHelper);
currentWeightGroup.appendChild(newError);
// Insert it after the target body fat input
var targetBFInput = document.getElementById('targetBodyFatPercentage');
if (targetBFInput && targetBFInput.parentNode && targetBFInput.parentNode.parentNode) {
targetBFInput.parentNode.parentNode.insertBefore(currentWeightGroup, targetBFInput.parentNode.nextSibling);
}
}
// Add event listeners for real-time updates and validation
document.getElementById('heightInput').addEventListener('input', calculateWeight);
document.getElementById('bodyFatPercentage').addEventListener('input', calculateWeight);
document.getElementById('targetBodyFatPercentage').addEventListener('input', calculateWeight);
if (document.getElementById('currentWeightInput')) {
document.getElementById('currentWeightInput').addEventListener('input', calculateWeight);
}
// Initial chart draw with empty/default values if desired, or wait for first calculation
// For now, we wait for the first calculation.
});