Understand your potential keto journey and estimate your progress.
Keto Weight Loss Timeline Calculator
Enter your weight in pounds (lbs).
Enter your goal weight in pounds (lbs).
0.5 lbs/week (Slow & Steady)
1 lb/week (Moderate)
1.5 lbs/week (Aggressive)
2 lbs/week (Very Aggressive)
Realistic average loss per week.
Typical for keto in the first week.
Estimate your current body fat (e.g., 30%).
Estimate your goal body fat (e.g., 20%).
Your Keto Weight Loss Projection
—
Weeks to Target: —
Total Fat Loss Needed: — lbs
Estimated Lean Mass Preserved: — lbs
Estimation based on your inputs, assuming consistent weekly fat loss after initial water weight reduction.
Key Assumptions
Average Weekly Fat Loss: — lbs
Initial Water Loss Phase: — weeks
Total Weight Loss Goal: — lbs
Weight Loss Progress Over Time
Week
Starting Weight (lbs)
Fat Loss This Week (lbs)
Water Loss This Week (lbs)
Ending Weight (lbs)
Est. Body Fat (%)
Weight Loss Trend and Body Fat Over Time
What is the Keto Weight Loss Calculator Timeline?
The Keto Weight Loss Calculator Timeline is a tool designed to help individuals estimate the duration of their ketogenic diet journey to reach a specific weight goal. It takes into account various personal factors, such as current weight, target weight, desired weekly weight loss rate, and initial water loss, to provide a projected timeline. This calculator is particularly useful for those embarking on or considering the ketogenic lifestyle, offering a data-driven perspective on what progress might look like over weeks and months. It aims to demystify the weight loss process on keto, setting realistic expectations and aiding in long-term adherence.
Who should use it? Anyone considering or currently following a ketogenic diet to lose weight can benefit from this calculator. Whether you're looking for a rough estimate, trying to set achievable goals, or simply curious about the potential timeframe, this tool provides valuable insights. It's especially helpful for individuals who want to understand how different weekly weight loss targets might impact their overall journey duration.
Common misconceptions surrounding keto weight loss include the idea that all initial weight loss is pure fat, or that rapid loss is always sustainable. In reality, much of the initial rapid decrease is often water weight due to glycogen depletion. Furthermore, extremely aggressive weight loss targets can be unsustainable and potentially lead to muscle loss. This calculator helps address these by differentiating between water and fat loss and allowing users to set more realistic rates.
Keto Weight Loss Calculator Timeline Formula and Mathematical Explanation
The calculation for the Keto Weight Loss Calculator Timeline involves several steps to provide a comprehensive projection. It aims to estimate time to reach target weight, considering both water and fat loss components.
Step-by-Step Derivation
Calculate Total Weight to Lose: This is the difference between current weight and target weight.
Estimate Initial Water Weight Loss: This is a one-time reduction typically occurring in the first week of keto.
Calculate Target Fat Loss: This is the total weight to lose minus the initial water weight loss.
Determine Weeks for Fat Loss: Divide the target fat loss by the chosen average weekly fat loss rate.
Calculate Total Time: Add the initial water loss phase (usually 1 week) to the weeks required for fat loss.
Estimate Lean Mass Preserved: This is a more complex calculation, but a simplified approach assumes a certain ratio of fat loss to lean mass preservation. For a healthier rate, we can estimate based on total weight lost and the typical body fat composition goal. A common guideline is that for every 1 pound of fat lost, a smaller fraction might be lean mass, especially with adequate protein and exercise. We'll calculate the total lean mass at current weight and target weight, and see the difference.
Generate Weekly Projections: Simulate week by week, accounting for initial water loss, then steady fat loss, and tracking estimated body fat percentage.
Variable Explanations
Here are the variables used in our Keto Weight Loss Calculator Timeline:
Variable
Meaning
Unit
Typical Range
Current Weight
The starting weight of the individual.
lbs
50 – 500+
Target Weight
The desired weight goal.
lbs
50 – 500+
Desired Weekly Weight Loss Rate
The average amount of weight the user aims to lose each week (primarily fat).
lbs/week
0.5 – 2.0
Initial Water Weight Loss
The estimated amount of water weight lost in the first week of keto.
lbs
2 – 10
Current Body Fat Percentage
The estimated percentage of body weight that is fat.
%
5 – 60
Target Body Fat Percentage
The desired percentage of body weight that is fat.
%
5 – 50
Total Weight to Lose
Calculated: Current Weight – Target Weight.
lbs
N/A
Target Fat Loss
Total Weight to Lose – Initial Water Weight Loss.
lbs
N/A
Weeks to Target
Calculated: Target Fat Loss / Desired Weekly Weight Loss Rate.
weeks
N/A
Total Estimated Timeline
1 (for water loss) + Weeks to Target.
weeks
N/A
Current Lean Mass
Calculated: Current Weight * (1 – Current Body Fat % / 100).
Current Lean Mass – Target Lean Mass (this assumes lean mass is lost proportionally or user has targeted lean mass loss). A more accurate model accounts for maintaining lean mass. We will use Current Lean Mass – Target Lean Mass as a proxy for total lean mass change.
lbs
N/A
Practical Examples (Real-World Use Cases)
Let's explore how the Keto Weight Loss Calculator Timeline can be used with practical scenarios:
Example 1: Moderate Weight Loss Goal
Scenario: Sarah wants to lose about 20 lbs. She's currently 160 lbs and wants to reach 140 lbs. She feels comfortable aiming for a 1 lb/week loss rate and estimates losing 4 lbs of water weight initially. Her current body fat is 35%, and she aims for 28%.
Total Estimated Timeline: 1 (water) + 16 = 17 weeks
Current Lean Mass: 160 * (1 – 35/100) = 104 lbs
Target Lean Mass: 140 * (1 – 28/100) = 100.8 lbs
Estimated Lean Mass Preserved: 104 – 100.8 = 3.2 lbs (This calculation shows total lean mass change, implying ~0.8 lbs of lean mass might be lost along with 16 lbs of fat, assuming proportions hold).
Interpretation: Sarah can expect her journey to take approximately 17 weeks. This includes an initial week of water loss, followed by 16 weeks of steady fat loss. She's projected to preserve a significant portion of her lean mass, given her goal aligns with losing fat primarily. This provides a clear target and helps her stay motivated.
Example 2: Significant Weight Loss Goal with Aggressive Rate
Scenario: Mark weighs 220 lbs and wants to reach 180 lbs, a 40 lb loss. He's motivated and aims for a 1.5 lbs/week loss rate, anticipating 6 lbs of initial water loss. His current body fat is 40%, and he wants to reach 30%.
Estimated Lean Mass Preserved: 132 – 126 = 6 lbs (This suggests ~1 lb of lean mass might be lost for every ~6 lbs of fat lost, which is a reasonable ratio, especially if protein intake and exercise are prioritized).
Interpretation: Mark's goal of losing 40 lbs on keto is estimated to take around 24 weeks. His more aggressive weekly rate significantly shortens the timeline compared to Sarah's, but he needs to be mindful of maintaining muscle mass. The calculator highlights that his 1.5 lbs/week target is aggressive and requires consistent effort.
How to Use This Keto Weight Loss Calculator Timeline
Using the Keto Weight Loss Calculator Timeline is straightforward. Follow these steps to get your personalized projection:
Input Current Weight: Enter your current weight in pounds (lbs) in the 'Current Weight' field.
Input Target Weight: Enter your desired goal weight in pounds (lbs) in the 'Target Weight' field.
Select Weekly Loss Rate: Choose a realistic 'Desired Weekly Weight Loss Rate' from the dropdown. Rates between 1-2 lbs per week are generally considered healthy and sustainable for fat loss.
Estimate Initial Water Loss: Input your best guess for the 'Initial Water Weight Loss' in pounds (lbs). This is typically higher in the first week of keto.
Input Body Fat Percentages: Provide your estimated 'Current Body Fat Percentage' and your 'Target Body Fat Percentage'. This helps refine estimations related to lean mass preservation.
Click 'Calculate Timeline': Once all fields are filled, click the button. The calculator will instantly display your projected timeline and key metrics.
How to Read Results
Primary Result (Estimated Timeline): This is your main projection in weeks.
Intermediate Values: Understand your 'Weeks to Target' (for fat loss specifically), 'Total Fat Loss Needed', and 'Estimated Lean Mass Preserved'.
Key Assumptions: Review the underlying factors like your chosen average weekly fat loss and initial water loss phase.
Table & Chart: The table and chart visually represent your progress week-by-week, showing estimated weight, fat loss, and body fat percentage changes.
Decision-Making Guidance
Use the results to:
Set Realistic Goals: If the timeline seems too long, consider if a slightly higher, yet still safe, weekly loss rate is feasible, or if your target weight is too ambitious for the timeframe.
Stay Motivated: Having a clear, calculated timeline can be a powerful motivator. Track your progress against the projection.
Adjust Strategy: If you're consistently losing faster or slower than projected, you may need to adjust your diet, exercise, or re-evaluate your input assumptions. Remember, this is an estimate.
Focus on Health: Ensure your chosen rate prioritizes fat loss while preserving lean muscle mass, as indicated by the 'Estimated Lean Mass Preserved' metric.
Key Factors That Affect Keto Weight Loss Results
While the Keto Weight Loss Calculator Timeline provides an estimate, numerous real-world factors can influence your actual progress. Understanding these is crucial for managing expectations and adapting your approach:
Metabolic Adaptation: Over time, your metabolism might adapt to a lower calorie intake, slowing down weight loss. This calculator uses a fixed rate, but your body's response can vary.
Hormonal Fluctuations: Stress hormones (like cortisol) and other hormonal changes (e.g., menstrual cycles) can impact water retention and fat loss.
Exercise Consistency and Intensity: Adding regular exercise, particularly strength training, can boost metabolism, preserve lean muscle mass, and potentially increase the rate of fat loss beyond what the calculator assumes. High-intensity interval training (HIIT) can be particularly effective.
Dietary Adherence and Accuracy: The ketogenic diet requires strict carbohydrate restriction. Inaccuracies in tracking macros (carbs, protein, fat) or frequent "cheat" days can hinder ketosis and slow down fat loss. The calculator assumes consistent adherence.
Sleep Quality and Quantity: Poor sleep disrupts hormones like ghrelin and leptin (appetite regulators) and increases cortisol, which can negatively impact weight loss efforts and increase cravings.
Individual Response to Macronutrients: People respond differently to fat and protein intake. Some may find that higher protein helps preserve muscle, while others might experience a slight "gluconeogenic" effect, slowing ketosis. Caloric deficit remains paramount.
Hydration and Electrolyte Balance: Especially in the initial phase of keto, maintaining proper hydration and electrolyte balance (sodium, potassium, magnesium) is vital for energy levels and can prevent side effects that might derail progress.
Underlying Health Conditions: Conditions like hypothyroidism or PCOS can significantly affect metabolism and weight loss, requiring personalized medical advice beyond generic calculator estimates.
Frequently Asked Questions (FAQ)
Q1: Is the calculated timeline guaranteed?
No, the timeline is an estimate based on averages and your inputs. Individual results vary significantly due to genetics, adherence, activity levels, and metabolic responses. Use it as a guide, not a strict deadline.
Q2: Why is initial water weight loss so high on keto?
When you drastically reduce carbohydrates, your body uses up its stored glycogen. Glycogen binds to water, so as glycogen stores deplete, water is released. This leads to rapid initial weight loss, which is temporary.
Q3: What is a healthy weekly weight loss rate?
For most individuals, a sustainable and healthy rate of fat loss is between 1 to 2 pounds per week. Losing weight faster than this can increase the risk of muscle loss, nutrient deficiencies, and gallstones.
Q4: Can I lose more than 2 lbs per week on keto?
While possible, especially for individuals with a large amount of weight to lose, aiming for significantly more than 2 lbs per week is generally not recommended for long-term health. It often leads to unsustainable practices and potential muscle loss.
Q5: How does body fat percentage affect the calculation?
Body fat percentage helps estimate lean mass. As you lose weight, it's crucial to lose fat while preserving muscle. The calculator uses body fat percentages to give an idea of lean mass preservation, highlighting the importance of body composition alongside scale weight.
Q6: What if my actual weight loss is different from the projection?
Don't get discouraged. Track your progress and adjust your inputs or expectations. If you're consistently off track, consult with a healthcare professional or a registered dietitian.
Q7: Does this calculator account for plateaus?
The calculator uses a consistent average weekly loss rate for simplicity. Real-world keto journeys often involve plateaus where weight loss temporarily stalls. These are not explicitly modeled but can extend the actual timeline beyond the estimate.
Q8: Should I focus only on the timeline or also on body composition?
Focusing solely on the scale can be misleading. Prioritize losing fat while maintaining or even building lean muscle mass. The 'Estimated Lean Mass Preserved' metric and the body fat percentage tracking in the table/chart are important indicators of progress towards a healthier body composition.
Q9: How accurate is the initial water weight loss estimate?
The initial water weight loss is highly variable. Factors like your previous diet, glycogen stores, and hydration levels play a role. The calculator uses a default estimate, but yours might be higher or lower.
Q10: Can this calculator be used for muscle gain estimations on keto?
No, this calculator is specifically designed for estimating weight loss timelines on a ketogenic diet. Muscle gain requires a different approach focused on caloric surplus and specific training protocols.
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var targetWeightInput = document.getElementById('targetWeight');
var weeklyWeightLossRateInput = document.getElementById('weeklyWeightLossRate');
var initialWaterLossInput = document.getElementById('initialWaterLoss');
var bodyFatPercentageInput = document.getElementById('bodyFatPercentage');
var targetBodyFatPercentageInput = document.getElementById('targetBodyFatPercentage');
var currentWeightError = document.getElementById('currentWeightError');
var targetWeightError = document.getElementById('targetWeightError');
var weeklyWeightLossRateError = document.getElementById('weeklyWeightLossRateError');
var initialWaterLossError = document.getElementById('initialWaterLossError');
var bodyFatPercentageError = document.getElementById('bodyFatPercentageError');
var targetBodyFatPercentageError = document.getElementById('targetBodyFatPercentageError');
var resultsSection = document.getElementById('resultsSection');
var primaryResult = document.getElementById('primaryResult');
var weeksToTargetDiv = document.getElementById('weeksToTarget');
var totalFatLossDiv = document.getElementById('totalFatLoss');
var leanMassPreservationDiv = document.getElementById('leanMassPreservation');
var assumptionFatLossPerWeekDiv = document.getElementById('assumptionFatLossPerWeek');
var assumptionInitialPhaseDiv = document.getElementById('assumptionInitialPhase');
var assumptionTotalWeightLossDiv = document.getElementById('assumptionTotalWeightLoss');
var progressTableBody = document.getElementById('progressTableBody');
var chartInstance = null;
var weightLossChartCanvas = document.getElementById('weightLossChart').getContext('2d');
function validateInput(inputElement, errorElement, min, max, label) {
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if (isNaN(value) || inputElement.value.trim() === "") {
errorMessage = label + " is required.";
} else if (value max) {
errorMessage = label + " cannot be more than " + max + ".";
}
errorElement.textContent = errorMessage;
return errorMessage === "";
}
function calculateTimeline() {
var isValid = true;
isValid &= validateInput(currentWeightInput, currentWeightError, 1, 1000, "Current Weight");
isValid &= validateInput(targetWeightInput, targetWeightError, 1, 1000, "Target Weight");
isValid &= validateInput(initialWaterLossInput, initialWaterLossError, 0, 50, "Initial Water Loss");
isValid &= validateInput(bodyFatPercentageInput, bodyFatPercentageError, 1, 99, "Current Body Fat Percentage");
isValid &= validateInput(targetBodyFatPercentageInput, targetBodyFatPercentageError, 1, 99, "Target Body Fat Percentage");
if (!isValid) {
resultsSection.style.display = 'none';
return;
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var currentWeight = parseFloat(currentWeightInput.value);
var targetWeight = parseFloat(targetWeightInput.value);
var weeklyWeightLossRate = parseFloat(weeklyWeightLossRateInput.value);
var initialWaterLoss = parseFloat(initialWaterLossInput.value);
var currentBodyFat = parseFloat(bodyFatPercentageInput.value);
var targetBodyFat = parseFloat(targetBodyFatPercentageInput.value);
if (currentWeight <= targetWeight) {
currentWeightError.textContent = "Current weight must be greater than target weight.";
resultsSection.style.display = 'none';
return;
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if (currentBodyFat <= targetBodyFat) {
targetBodyFatPercentageError.textContent = "Target body fat percentage must be less than current.";
resultsSection.style.display = 'none';
return;
}
var totalWeightToLose = currentWeight – targetWeight;
var targetFatLoss = totalWeightToLose – initialWaterLoss;
if (targetFatLoss 0 ? targetFatLoss / weeklyWeightLossRate : 0;
var totalEstimatedTimelineWeeks = 1 + weeksToTargetFatLoss; // 1 week for initial water loss
var currentLeanMass = currentWeight * (1 – (currentBodyFat / 100));
var targetLeanMass = targetWeight * (1 – (targetBodyFat / 100));
var estimatedLeanMassPreserved = currentLeanMass – targetLeanMass;
// Ensure lean mass preserved is not negative (if target weight is significantly less and body fat goal is similar)
if (estimatedLeanMassPreserved targetW) { // Check if target reached after water loss
tableRows += '
';
tableRows += '
1
';
tableRows += '
' + startWeight.toFixed(1) + '
';
tableRows += '
' + fatLossThisWeek.toFixed(1) + '
';
tableRows += '
' + waterLossThisWeek.toFixed(1) + '
';
tableRows += '
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';
tableRows += '
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tableRows += '
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chartDataLabels.push('Week 1');
chartDataWeight.push(endingWeight);
chartDataBodyFat.push(endingBF);
totalWeeks = 1;
}
// Subsequent Weeks: Fat Loss
var weeksForFatLoss = remainingFatLoss > 0 ? Math.ceil(remainingFatLoss / weeklyRate) : 0;
if (weeksForFatLoss > 0 && endingWeight > targetW) {
for (var i = 0; i targetWeightAtThisBF && targetBF < currentBodyFat) {
// If calculated total weight is *more* than what's needed at target BF,
// it means we've overshot the target BF based on fat loss alone.
// We need to adjust to hit the target weight at the target BF.
// This implies more lean mass was lost than intended or the rate was too high.
// For simplicity in this chart, let's just cap the BF decrease.
var bfDiff = currentBodyFat – targetBF;
var proportionalBFChange = (weightLossFromFat / currentTotalWeight) * currentBodyFat;
var estimatedBFDecrease = proportionalBFChange; // Simplified
endingBF = Math.max(targetBF, currentBodyFat – estimatedBFDecrease);
} else {
endingBF = calculatedEndingBF;
}
endingBF = Math.max(targetBF, endingBF); // Ensure BF doesn't drop below target
endingWeight = nextTotalWeight;
remainingFatLoss -= currentWeekFatLoss;
if (endingWeight <= targetW || remainingFatLoss targetW) endingBF = Math.max(endingBF, targetW * (1 – targetBF/100) / targetW * 100) // Ensure BF target aligns with weight target
}
tableRows += '
';
tableRows += '
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';
tableRows += '
' + currentTotalWeight.toFixed(1) + '
';
tableRows += '
' + currentWeekFatLoss.toFixed(1) + '
';
tableRows += '
0.0
'; // Assuming only fat loss after week 1
tableRows += '
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';
tableRows += '
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';
tableRows += '
';
chartDataLabels.push('Week ' + weekNum);
chartDataWeight.push(endingWeight);
chartDataBodyFat.push(endingBF);
totalWeeks = weekNum;
if (remainingFatLoss 0 && chartDataWeight[chartDataWeight.length – 1] > targetW) {
chartDataWeight[chartDataWeight.length – 1] = targetW;
chartDataBodyFat[chartDataBodyFat.length – 1] = targetBF;
// Update last table row if it exists
var rows = progressTableBody.getElementsByTagName('tr');
if (rows.length > 0) {
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lastRowCells[4].textContent = targetW.toFixed(1); // Ending Weight
lastRowCells[5].textContent = targetBF.toFixed(1) + '%'; // Est. Body Fat
}
}
progressTableBody.innerHTML = tableRows;
// Update Chart
if (chartInstance) {
chartInstance.destroy();
}
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type: 'line',
data: {
labels: chartDataLabels,
datasets: [
{
label: 'Weight (lbs)',
data: chartDataWeight,
borderColor: 'rgb(75, 192, 192)',
backgroundColor: 'rgba(75, 192, 192, 0.1)',
tension: 0.1,
fill: false,
yAxisID: 'y1', // Assign to the left y-axis
},
{
label: 'Body Fat (%)',
data: chartDataBodyFat,
borderColor: 'rgb(255, 99, 132)',
backgroundColor: 'rgba(255, 99, 132, 0.1)',
tension: 0.1,
fill: false,
yAxisID: 'y2', // Assign to the right y-axis
}
]
},
options: {
responsive: true,
maintainAspectRatio: false,
scales: {
x: {
title: {
display: true,
text: 'Timeline'
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},
y1: { // Left Y-axis for Weight
type: 'linear',
position: 'left',
title: {
display: true,
text: 'Weight (lbs)'
},
ticks: {
beginAtZero: false // Weight doesn't start at 0
}
},
y2: { // Right Y-axis for Body Fat
type: 'linear',
position: 'right',
title: {
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text: 'Body Fat (%)'
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min: 0, // Body fat percentage starts at 0
max: 100,
ticks: {
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grid: {
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plugins: {
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function resetCalculator() {
currentWeightInput.value = 180;
targetWeightInput.value = 150;
weeklyWeightLossRateInput.value = 1;
initialWaterLossInput.value = 5;
bodyFatPercentageInput.value = 30;
targetBodyFatPercentageInput.value = 20;
currentWeightError.textContent = "";
targetWeightError.textContent = "";
weeklyWeightLossRateError.textContent = "";
initialWaterLossError.textContent = "";
bodyFatPercentageError.textContent = "";
targetBodyFatPercentageError.textContent = "";
resultsSection.style.display = 'none';
if (chartInstance) {
chartInstance.destroy();
chartInstance = null;
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progressTableBody.innerHTML = ";
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function copyResults() {
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resultText += "Total Fat Loss Needed: " + totalFatLossDiv.getElementsByTagName('span')[0].textContent + "\n";
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resultText += "- Initial Water Loss Phase: " + assumptionInitialPhaseDiv.getElementsByTagName('span')[0].textContent + "\n";
resultText += "- Total Weight Loss Goal: " + assumptionTotalWeightLossDiv.getElementsByTagName('span')[0].textContent + "\n\n";
resultText += "Progress Table Data:\n";
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if (rows.length > 0) {
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cells[2].textContent + "\t" +
cells[3].textContent + "\t" +
cells[4].textContent + "\t" +
cells[5].textContent + "\n";
}
} else {
resultText += "No progress data available yet.\n";
}
navigator.clipboard.writeText(resultText).then(function() {
alert('Results copied to clipboard!');
}, function(err) {
console.error('Failed to copy: ', err);
alert('Failed to copy results. Please try again.');
});
}
// Initial calculation on load if inputs have default values
document.addEventListener('DOMContentLoaded', function() {
calculateTimeline();
// Prevent default form submission if calculator is within a form
var form = document.querySelector('.loan-calc-container').closest('form');
if (form) {
form.addEventListener('submit', function(e) {
e.preventDefault();
calculateTimeline();
});
}
});
// Re-calculate on input change for real-time updates
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for (var i = 0; i < inputElements.length; i++) {
inputElements[i].addEventListener('input', calculateTimeline);
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