Healthy Weight Loss Rate Calculator

Healthy Weight Loss Rate Calculator & Guide :root { –primary-color: #004a99; –success-color: #28a745; –background-color: #f8f9fa; –text-color: #333; –card-background: #ffffff; –border-color: #dee2e6; –shadow-color: rgba(0, 0, 0, 0.1); } body { font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; background-color: var(–background-color); color: var(–text-color); margin: 0; padding: 0; line-height: 1.6; } .container { max-width: 1000px; margin: 20px auto; padding: 20px; background-color: var(–card-background); border-radius: 8px; box-shadow: 0 4px 12px var(–shadow-color); } h1, h2, h3 { color: var(–primary-color); text-align: center; } h1 { margin-bottom: 20px; } h2 { margin-top: 30px; margin-bottom: 20px; border-bottom: 2px solid var(–primary-color); padding-bottom: 5px; } h3 { margin-top: 15px; margin-bottom: 10px; } .calculator-wrapper { margin-top: 20px; padding: 30px; border: 1px solid var(–border-color); border-radius: 8px; background-color: var(–card-background); box-shadow: 0 2px 8px var(–shadow-color); } .input-group { margin-bottom: 20px; text-align: left; } .input-group label { display: block; margin-bottom: 8px; font-weight: bold; color: var(–primary-color); } .input-group input[type="number"], .input-group input[type="text"], .input-group select { width: calc(100% – 20px); padding: 10px; border: 1px solid var(–border-color); border-radius: 4px; font-size: 1rem; margin-top: 5px; box-sizing: border-box; } .input-group input[type="number"]:focus, .input-group input[type="text"]:focus, .input-group select:focus { outline: none; border-color: var(–primary-color); box-shadow: 0 0 0 2px rgba(0, 74, 153, 0.2); } .input-group .helper-text { font-size: 0.85rem; color: #6c757d; margin-top: 5px; display: block; } .input-group .error-message { color: #dc3545; font-size: 0.85rem; margin-top: 5px; display: none; /* Hidden by default */ } .error-message.visible { display: block; } .button-group { text-align: center; margin-top: 30px; } button { background-color: var(–primary-color); color: white; border: none; padding: 12px 25px; border-radius: 5px; font-size: 1.1rem; cursor: pointer; margin: 0 10px; transition: background-color 0.3s ease; } button:hover { background-color: #003366; } button.reset-button { background-color: #6c757d; } button.reset-button:hover { background-color: #5a6268; } button.copy-button { background-color: #ffc107; color: #212529; } button.copy-button:hover { background-color: #e0a800; } #results { margin-top: 30px; padding: 25px; border: 1px solid var(–border-color); border-radius: 8px; background-color: #e9ecef; text-align: center; } #results h3 { margin-top: 0; color: var(–text-color); } .primary-result { font-size: 2.5rem; font-weight: bold; color: var(–success-color); margin: 15px 0; padding: 15px; background-color: rgba(40, 167, 69, 0.1); border-radius: 6px; display: inline-block; } .intermediate-results { margin-top: 20px; display: flex; justify-content: space-around; flex-wrap: wrap; } .intermediate-result-item { margin: 10px; padding: 10px 15px; background-color: var(–card-background); border-radius: 5px; box-shadow: 0 1px 4px var(–shadow-color); text-align: center; } .intermediate-result-item strong { display: block; font-size: 1.2rem; color: var(–primary-color); } .intermediate-result-item span { font-size: 0.9rem; color: #6c757d; } .formula-explanation { margin-top: 20px; font-size: 0.9rem; color: #6c757d; text-align: center; } table { width: 100%; border-collapse: collapse; margin-top: 20px; box-shadow: 0 2px 8px var(–shadow-color); } th, td { padding: 12px 15px; text-align: left; border: 1px solid var(–border-color); } th { background-color: var(–primary-color); color: white; font-weight: bold; } tr:nth-child(even) { background-color: #f2f2f2; } caption { font-size: 1.1rem; font-weight: bold; color: var(–primary-color); margin-bottom: 10px; text-align: center; } #chartContainer { width: 100%; max-width: 600px; margin: 30px auto; background-color: var(–card-background); padding: 20px; border-radius: 8px; box-shadow: 0 2px 8px var(–shadow-color); } #chartContainer canvas { display: block; /* Prevent extra space below canvas */ } .chart-caption { font-size: 1rem; color: #6c757d; text-align: center; margin-top: 10px; } .article-section { margin-top: 40px; padding-top: 20px; border-top: 1px solid var(–border-color); } .article-section p { margin-bottom: 15px; } .article-section ul { margin-left: 20px; margin-bottom: 15px; } .article-section li { margin-bottom: 8px; } .faq-item { margin-bottom: 15px; } .faq-item strong { display: block; color: var(–primary-color); cursor: pointer; margin-bottom: 5px; } .faq-item p { margin-left: 15px; display: none; /* Hidden by default */ } .faq-item.open p { display: block; } .internal-links-section ul { list-style: none; padding: 0; } .internal-links-section li { margin-bottom: 10px; } .internal-links-section a { color: var(–primary-color); text-decoration: none; font-weight: bold; } .internal-links-section a:hover { text-decoration: underline; } .internal-links-section p { font-size: 0.9rem; color: #6c757d; } /* Utility Classes */ .text-center { text-align: center; } .text-primary { color: var(–primary-color); } .text-success { color: var(–success-color); } .font-weight-bold { font-weight: bold; }

Healthy Weight Loss Rate Calculator

Enter your current weight in kilograms (kg).
Enter your desired weight in kilograms (kg).
The average daily calorie deficit needed (e.g., 750 kcal/day).
Your current body fat percentage (e.g., 25%). Used for context, not direct calculation.

Your Weight Loss Projection

Weeks to Target
Lbs Lost Per Week
Kg Lost Per Week
Total Loss (Kg)
Formula: Weeks to Target = (Total Weight Loss in Kg * 7700) / Weekly Calorie Deficit. Lbs/Week = (Total Weight Loss in Kg * 2.20462) / Weeks to Target. Kg/Week = Total Weight Loss in Kg / Weeks to Target.
Projected Weight Loss Over Time
Healthy Weight Loss Benchmarks
Metric Recommended Range Notes
Weight Loss Rate (Kg/Week) 0.5 – 1.0 Kg/Week Sustainable and healthy loss. Faster may lead to muscle loss.
Calorie Deficit (Daily) 500 – 1000 kcal/day Balancing deficit with nutrient intake is key.
Total Loss (Percentage) 5-10% of body weight Initial safe goal for many health benefits.

What is Healthy Weight Loss Rate?

The concept of a **healthy weight loss rate calculator** helps individuals understand the pace at which they can sustainably and safely shed excess pounds. It's not just about the number on the scale, but about adopting habits that promote long-term health and well-being. A healthy rate of weight loss is generally considered to be between 0.5 to 1.0 kilograms (approximately 1 to 2 pounds) per week. This pace allows for the loss of fat mass while preserving lean muscle mass, which is crucial for maintaining metabolism and overall physical function. Using a **healthy weight loss rate calculator** can provide a personalized estimate based on individual factors, offering a realistic timeline for achieving weight goals.

This tool is particularly useful for individuals who are embarking on a weight loss journey, those who have specific weight targets, or anyone curious about the physiological process of losing weight. It can help set achievable goals and manage expectations, preventing discouragement that can arise from unrealistic timelines. Understanding your potential **healthy weight loss rate** empowers you to make informed decisions about your diet and exercise plans.

A common misconception is that faster weight loss is always better. While significant initial drops in weight can be motivating, rapid loss often includes water and muscle, not just fat. This can lead to a slower metabolism, fatigue, and a higher likelihood of regaining weight. Another misconception is that weight loss is purely about willpower; it's a complex interplay of metabolism, hormones, diet, activity levels, and even sleep and stress. A **healthy weight loss rate calculator** focuses on the energy balance principle, which is a foundational aspect of sustainable weight management.

Healthy Weight Loss Rate Formula and Mathematical Explanation

The core principle behind calculating a **healthy weight loss rate** is the energy balance equation: weight change is proportional to the net energy balance. To lose weight, energy expenditure must exceed energy intake, creating a calorie deficit. Approximately 7,700 kilocalories (kcal) are equivalent to one kilogram of fat. Therefore, a consistent calorie deficit leads to predictable fat loss.

The formula implemented in our **healthy weight loss rate calculator** breaks down the projection:

  1. Total Weight Loss in Kilograms: This is the difference between your current weight and your target weight.
  2. Total Calorie Deficit Needed: To lose the total weight in kilograms, you multiply the total weight loss by the approximate kcal per kg of fat (7700 kcal/kg).
  3. Weeks to Target: This is calculated by dividing the total calorie deficit needed by your *specified weekly calorie deficit*.
  4. Kilograms Lost Per Week: This is derived by dividing the total weight loss in kilograms by the calculated weeks to target.
  5. Pounds Lost Per Week: This is a conversion of kilograms lost per week (1 kg ≈ 2.20462 lbs).

Mathematically, the primary calculations are:

Total Weight Loss (kg) = Current Weight (kg) - Target Weight (kg)

Total Calorie Deficit Required (kcal) = Total Weight Loss (kg) * 7700 kcal/kg

Weeks to Target = Total Calorie Deficit Required (kcal) / Weekly Calorie Deficit (kcal/week)

Kg Lost Per Week = Total Weight Loss (kg) / Weeks to Target

Lbs Lost Per Week = Kg Lost Per Week * 2.20462

It's important to note that the calculator assumes a consistent weekly deficit and that all weight lost is fat, which is a simplification. Factors like muscle mass, metabolic adaptation, and non-linear responses to diet and exercise can influence the actual rate.

Variables Used in Healthy Weight Loss Rate Calculation
Variable Meaning Unit Typical Range
Current Weight Your starting body weight. Kilograms (kg) 18 – 500+ kg
Target Weight Your desired body weight. Kilograms (kg) 18 – 500+ kg (must be less than current weight for loss)
Weekly Calorie Deficit The net reduction in calories consumed versus burned per week. Kilocalories (kcal)/week 3500 – 7000 kcal/week (for 0.5-1kg loss/week)
Weeks to Target Estimated time to reach the target weight. Weeks Variable, depends on deficit and total loss
Lbs Lost Per Week Estimated rate of fat loss in pounds. Pounds (lbs)/week 1 – 2 lbs/week (for healthy rate)
Kg Lost Per Week Estimated rate of fat loss in kilograms. Kilograms (kg)/week 0.5 – 1.0 kg/week (for healthy rate)

Practical Examples (Real-World Use Cases)

Understanding the **healthy weight loss rate calculator** in practice can make the concept clearer. Here are a couple of scenarios:

Example 1: Moderate Weight Loss Goal

Scenario: Sarah currently weighs 80 kg and wants to reach a target weight of 70 kg. She aims for a sustainable approach and has determined she can maintain a weekly calorie deficit of 700 kcal through diet and exercise.

Inputs for Calculator:

  • Current Weight: 80 kg
  • Target Weight: 70 kg
  • Weekly Calorie Deficit: 700 kcal/week

Calculator Output:

  • Total Weight Loss: 10 kg
  • Total Calorie Deficit Required: 77,000 kcal
  • Weeks to Target: 110 weeks (77,000 kcal / 700 kcal/week) – *Note: This highlights a slow rate, prompting review.* Let's re-calculate assuming a more typical 750 kcal/day deficit, which is 5250 kcal/week.

Revised Calculation with 5250 kcal/week deficit:

  • Total Weight Loss: 10 kg
  • Total Calorie Deficit Required: 77,000 kcal
  • Weeks to Target: 14.67 weeks (77,000 kcal / 5250 kcal/week)
  • Kg Lost Per Week: 0.68 kg/week (10 kg / 14.67 weeks)
  • Lbs Lost Per Week: 1.50 lbs/week (0.68 kg/week * 2.20462)
  • Primary Result Highlighted: Approximately 0.7 Kg/Week loss.

Interpretation: Sarah can expect to lose roughly 0.7 kg per week, reaching her goal in about 15 weeks. This falls within the healthy range of 0.5-1.0 kg per week, indicating a sustainable and effective plan.

Example 2: Larger Weight Loss Goal with Faster Rate

Scenario: John weighs 120 kg and aims to reach 100 kg. He is committed to a significant lifestyle change and can sustain a higher weekly deficit of 1000 kcal per day (7000 kcal/week).

Inputs for Calculator:

  • Current Weight: 120 kg
  • Target Weight: 100 kg
  • Weekly Calorie Deficit: 7000 kcal/week

Calculator Output:

  • Total Weight Loss: 20 kg
  • Total Calorie Deficit Required: 154,000 kcal (20 kg * 7700 kcal/kg)
  • Weeks to Target: 22 weeks (154,000 kcal / 7000 kcal/week)
  • Kg Lost Per Week: 0.91 kg/week (20 kg / 22 weeks)
  • Lbs Lost Per Week: 2.00 lbs/week (0.91 kg/week * 2.20462)
  • Primary Result Highlighted: Approximately 0.9 Kg/Week loss.

Interpretation: John's plan is projected to result in a loss of about 0.9 kg per week, putting him on track to reach his goal in approximately 22 weeks. This rate is at the higher end of the healthy spectrum but still considered sustainable and safe for many individuals, provided adequate nutrient intake and appropriate exercise are maintained. It emphasizes the importance of a substantial deficit for larger weight loss goals.

How to Use This Healthy Weight Loss Rate Calculator

Using our **healthy weight loss rate calculator** is straightforward and designed to provide quick insights into your weight loss journey. Follow these simple steps:

  1. Enter Current Weight: Input your current body weight in kilograms (kg) into the "Current Weight" field.
  2. Enter Target Weight: Enter the weight in kilograms (kg) you aim to achieve in the "Target Weight" field. Ensure this is less than your current weight for a weight loss calculation.
  3. Specify Weekly Calorie Deficit: Input the average daily calorie deficit you plan to maintain, expressed as a weekly total (e.g., 500 kcal/day * 7 days/week = 3500 kcal/week). This deficit is the key driver of your weight loss rate. A common guideline for a healthy rate is 500-1000 kcal/day deficit.
  4. Optional: Body Fat Percentage: While not used in the primary calculation, entering your body fat percentage can provide context for interpreting your progress later.
  5. Click 'Calculate': Once all relevant fields are filled, click the "Calculate" button.

How to Read Results:

  • Primary Result (Highlighted): This shows your projected weight loss rate in kilograms per week. A rate between 0.5 and 1.0 kg/week is generally considered healthy and sustainable.
  • Weeks to Target: An estimate of how long it will take to reach your goal weight based on the inputs.
  • Lbs Lost Per Week & Kg Lost Per Week: These provide the estimated rate of loss in both common units.
  • Total Loss (Kg): The total amount of weight you aim to lose.
  • Chart: The dynamic chart visually represents your projected weight loss over time, making it easier to grasp the journey.
  • Table: The benchmark table provides context, showing recommended healthy ranges for comparison.

Decision-Making Guidance:

  • If your projected rate is significantly higher than 1.0 kg/week, consider if the deficit is too aggressive. It might lead to muscle loss or be unsustainable. You might increase your target weight slightly or reduce your weekly deficit.
  • If the projected time to reach your goal seems too long, review your weekly calorie deficit. Increasing it slightly (while staying within healthy limits) can speed up progress, but ensure it's realistic and nutritious.
  • Use the "Copy Results" button to save your projections or share them.
  • The "Reset" button allows you to quickly start over with default or new values.

Key Factors That Affect Healthy Weight Loss Rate Results

While our **healthy weight loss rate calculator** provides a valuable estimate, real-world weight loss is influenced by numerous factors beyond simple calorie math. Understanding these can help you adjust your expectations and strategy:

  1. Metabolic Adaptation: As you lose weight, your metabolism naturally slows down. Your body becomes more efficient at using fewer calories, which can reduce your **healthy weight loss rate** over time, even if your deficit remains the same. This means you might need to adjust your calorie intake or increase activity to maintain momentum.
  2. Muscle Mass vs. Fat Mass: The calculator assumes all lost weight is fat. However, aggressive deficits or insufficient protein intake can lead to muscle loss. Muscle is metabolically active, so losing it can further slow your metabolism. Strength training is crucial to preserve muscle during weight loss.
  3. Hormonal Fluctuations: Hormones like cortisol (stress), insulin (blood sugar regulation), ghrelin (hunger), and leptin (satiety) play significant roles. Stress, poor sleep, and certain medical conditions can disrupt these hormones, impacting appetite, fat storage, and your ability to maintain a **healthy weight loss rate**.
  4. Dietary Composition: The type of calories consumed matters. A diet rich in protein and fiber promotes satiety and helps preserve muscle, while highly processed foods can be less filling and may trigger cravings, making it harder to stick to a deficit.
  5. Exercise Type and Intensity: While the calculator bases projections on calorie deficit, the type of exercise impacts body composition. Cardiovascular exercise burns calories directly, while strength training builds muscle, boosting resting metabolism. A combination is usually most effective for a **healthy weight loss rate**.
  6. Hydration Levels: Water is essential for metabolic processes. Sometimes, thirst can be mistaken for hunger. Adequate hydration can support your **healthy weight loss rate** by aiding digestion and potentially boosting metabolism slightly.
  7. Sleep Quality and Duration: Poor sleep is linked to increased hunger hormones (ghrelin) and decreased satiety hormones (leptin), potentially leading to increased calorie intake and reduced energy for exercise. It can negatively affect your **healthy weight loss rate**.
  8. Medications and Medical Conditions: Certain medications (e.g., steroids, antidepressants) and underlying health conditions (e.g., hypothyroidism, PCOS) can affect metabolism and weight management, making it harder to achieve a predictable **healthy weight loss rate**. Consulting a healthcare provider is crucial in these cases.

Frequently Asked Questions (FAQ)

What is the safest rate of weight loss?

The safest rate of weight loss is generally considered to be 0.5 to 1.0 kilogram (1 to 2 pounds) per week. This pace is more likely to result in fat loss rather than muscle or water loss and is easier to sustain long-term.

Can I lose more than 1 kg per week?

Yes, it's possible, especially if you have a significant amount of weight to lose or are undertaking a very intensive exercise program. However, losing more than 1 kg per week consistently can increase the risk of nutrient deficiencies, muscle loss, gallstones, and fatigue. It's often not sustainable and may lead to weight regain. Consult with a healthcare professional before aiming for a rate higher than 1 kg/week.

Does the calculator account for exercise?

The calculator accounts for exercise indirectly through the "Weekly Calorie Deficit" input. Exercise contributes to your total daily energy expenditure, thus helping you achieve the desired deficit. It doesn't differentiate between diet-based deficit and exercise-based deficit; it only considers the net result.

What if my target weight is very close to my current weight?

If your target weight is very close to your current weight, the "Total Weight Loss" will be small. This means the "Weeks to Target" might be very short, even with a moderate deficit. The calculator will still provide an estimate, but remember that small changes can sometimes be harder to achieve due to natural daily fluctuations in weight.

How accurate is the 7700 kcal per kg of fat rule?

The 7700 kcal per kg of fat is an approximation. The actual energy content of fat can vary slightly, and the body's metabolic response to calorie restriction is complex. However, it serves as a widely accepted and practical guideline for estimating weight loss based on calorie deficits.

Is it okay to have days with no deficit?

Yes, it's perfectly fine and often more sustainable. A "weekly deficit" allows for flexibility. You might have days where you consume slightly more due to social events or cravings, as long as you compensate on other days to meet your average weekly deficit goal. Consistency over the week is key.

What should I do if my results seem unrealistic?

If the calculated time is excessively long or short, or the rate seems unachievable, review your inputs. Ensure your target weight is realistic and that your weekly calorie deficit is appropriate for your activity level and metabolism. It might indicate a need to adjust your plan or consult a professional.

How does body fat percentage affect my weight loss rate?

Body fat percentage itself doesn't directly alter the mathematical calculation of weight loss based on calorie deficit. However, it's a crucial indicator of health. A higher body fat percentage might mean you have more fat to lose, but focusing solely on scale weight can be misleading. Maintaining muscle mass (which has a higher density than fat) is key. The calculator includes it as an optional input for context, as a healthy weight loss journey involves improving body composition, not just reducing weight.

Related Tools and Internal Resources

© 2023 Your Financial Health Hub. All rights reserved.

var currentWeightInput = document.getElementById('currentWeight'); var targetWeightInput = document.getElementById('targetWeight'); var weeklyDeficitInput = document.getElementById('weeklyDeficit'); var bodyFatInput = document.getElementById('bodyFatPercentage'); var currentWeightError = document.getElementById('currentWeightError'); var targetWeightError = document.getElementById('targetWeightError'); var weeklyDeficitError = document.getElementById('weeklyDeficitError'); var bodyFatPercentageError = document.getElementById('bodyFatPercentageError'); var primaryResultDisplay = document.getElementById('primaryResult'); var weeksToTargetDisplay = document.getElementById('weeksToTarget'); var poundsPerWeekDisplay = document.getElementById('poundsPerWeek'); var kgPerWeekDisplay = document.getElementById('kgPerWeek'); var totalLossKgDisplay = document.getElementById('totalLossKg'); var weightLossChart; // Declare chart variable globally function isValidNumber(value) { return !isNaN(parseFloat(value)) && isFinite(value); } function updateChart() { if (weightLossChart) { weightLossChart.destroy(); } var currentWeight = parseFloat(currentWeightInput.value); var targetWeight = parseFloat(targetWeightInput.value); var weeklyDeficit = parseFloat(weeklyDeficitInput.value); var totalLossKg = currentWeight – targetWeight; var weeksToTarget = (totalLossKg * 7700) / weeklyDeficit; var kgPerWeek = totalLossKg / weeksToTarget; var lbsPerWeek = kgPerWeek * 2.20462; if (!isValidNumber(currentWeight) || !isValidNumber(targetWeight) || !isValidNumber(weeklyDeficit) || currentWeight <= targetWeight || weeklyDeficit <= 0) { // Don't draw chart if inputs are invalid or no loss is possible return; } var ctx = document.getElementById('weightLossChart').getContext('2d'); var labels = []; var weights = []; var weeks = 0; while (weeks <= weeksToTarget && weeks <= 52) { // Limit chart to 52 weeks for clarity labels.push(weeks.toFixed(1) + ' wks'); var projectedWeight = currentWeight – (kgPerWeek * weeks); weights.push(projectedWeight); weeks += weeksToTarget / 10; // Add points for a smoother curve, max 10 points + start/end if (weeksToTarget 0) weeks = weeksToTarget / 10; // Adjust increment for short durations } // Ensure the target weight is plotted if it's within the 52-week limit if (weeksToTarget <= 52 && !labels.includes(weeksToTarget.toFixed(1) + ' wks')) { labels.push(weeksToTarget.toFixed(1) + ' wks'); weights.push(targetWeight); } weightLossChart = new Chart(ctx, { type: 'line', data: { labels: labels, datasets: [{ label: 'Projected Weight (kg)', data: weights, borderColor: 'var(–primary-color)', backgroundColor: 'rgba(0, 74, 153, 0.2)', fill: true, tension: 0.1 }, { label: 'Target Weight', data: Array(labels.length).fill(targetWeight), // Flat line for target borderColor: 'var(–success-color)', borderDash: [5, 5], backgroundColor: 'rgba(40, 167, 69, 0.2)', fill: false, tension: 0 }] }, options: { responsive: true, maintainAspectRatio: true, scales: { y: { beginAtZero: false, title: { display: true, text: 'Weight (kg)' } }, x: { title: { display: true, text: 'Time' } } }, plugins: { tooltip: { callbacks: { label: function(context) { var label = context.dataset.label || ''; if (label) { label += ': '; } if (context.parsed.y !== null) { label += context.parsed.y.toFixed(1) + ' kg'; } return label; } } } } } }); } function calculateWeightLoss() { // Clear previous errors currentWeightError.classList.remove('visible'); targetWeightError.classList.remove('visible'); weeklyDeficitError.classList.remove('visible'); bodyFatPercentageError.classList.remove('visible'); var currentWeight = parseFloat(currentWeightInput.value); var targetWeight = parseFloat(targetWeightInput.value); var weeklyDeficit = parseFloat(weeklyDeficitInput.value); var bodyFatPercentage = parseFloat(bodyFatInput.value); var errors = false; if (!isValidNumber(currentWeight) || currentWeight <= 0) { currentWeightError.textContent = "Please enter a valid positive number for current weight."; currentWeightError.classList.add('visible'); errors = true; } if (!isValidNumber(targetWeight) || targetWeight <= 0) { targetWeightError.textContent = "Please enter a valid positive number for target weight."; targetWeightError.classList.add('visible'); errors = true; } if (currentWeight <= targetWeight) { targetWeightError.textContent = "Target weight must be less than current weight."; targetWeightError.classList.add('visible'); errors = true; } if (!isValidNumber(weeklyDeficit) || weeklyDeficit <= 0) { weeklyDeficitError.textContent = "Please enter a valid positive number for weekly calorie deficit."; weeklyDeficitError.classList.add('visible'); errors = true; } // Optional body fat validation if (bodyFatInput.value !== "" && (!isValidNumber(bodyFatPercentage) || bodyFatPercentage 100)) { bodyFatPercentageError.textContent = "Please enter a valid percentage between 0 and 100."; bodyFatPercentageError.classList.add('visible'); // Not making this a hard error, as it's optional } if (errors) { primaryResultDisplay.textContent = '–'; weeksToTargetDisplay.textContent = '–'; poundsPerWeekDisplay.textContent = '–'; kgPerWeekDisplay.textContent = '–'; totalLossKgDisplay.textContent = '–'; if (weightLossChart) weightLossChart.destroy(); // Clear chart if errors return; } var totalLossKg = currentWeight – targetWeight; var totalCalorieDeficitRequired = totalLossKg * 7700; var weeksToTarget = totalCalorieDeficitRequired / weeklyDeficit; var kgPerWeek = totalLossKg / weeksToTarget; var lbsPerWeek = kgPerWeek * 2.20462; primaryResultDisplay.textContent = kgPerWeek.toFixed(2) + ' Kg/Week'; weeksToTargetDisplay.textContent = weeksToTarget.toFixed(1); poundsPerWeekDisplay.textContent = lbsPerWeek.toFixed(2); kgPerWeekDisplay.textContent = kgPerWeek.toFixed(2); totalLossKgDisplay.textContent = totalLossKg.toFixed(1); updateChart(); } function resetCalculator() { currentWeightInput.value = 70; targetWeightInput.value = 65; weeklyDeficitInput.value = 750; // Represents 750 kcal/day deficit bodyFatInput.value = 25; // Clear errors currentWeightError.textContent = "; currentWeightError.classList.remove('visible'); targetWeightError.textContent = "; targetWeightError.classList.remove('visible'); weeklyDeficitError.textContent = "; weeklyDeficitError.classList.remove('visible'); bodyFatPercentageError.textContent = "; bodyFatPercentageError.classList.remove('visible'); calculateWeightLoss(); // Recalculate with defaults } function copyResults() { var currentWeight = currentWeightInput.value; var targetWeight = targetWeightInput.value; var weeklyDeficit = weeklyDeficitInput.value; var bodyFat = bodyFatInput.value; var primaryResult = primaryResultDisplay.textContent; var weeksToTarget = weeksToTargetDisplay.textContent; var lbsPerWeek = poundsPerWeekDisplay.textContent; var kgPerWeek = kgPerWeekDisplay.textContent; var totalLossKg = totalLossKgDisplay.textContent; var assumptions = "Assumptions:\n"; assumptions += "- Weekly Calorie Deficit: " + weeklyDeficit + " kcal/week\n"; assumptions += "- 1 kg fat = 7700 kcal\n"; if (bodyFat) { assumptions += "- Current Body Fat Percentage: " + bodyFat + "%\n"; } var copyText = "— Healthy Weight Loss Projection —\n\n"; copyText += "Current Weight: " + currentWeight + " kg\n"; copyText += "Target Weight: " + targetWeight + " kg\n"; copyText += "————————————-\n\n"; copyText += "Your Projection:\n"; copyText += "Projected Loss Rate: " + primaryResult + "\n"; copyText += "Weeks to Target: " + weeksToTarget + "\n"; copyText += "Lbs Lost Per Week: " + lbsPerWeek + "\n"; copyText += "Kg Lost Per Week: " + kgPerWeek + "\n"; copyText += "Total Loss Goal: " + totalLossKg + "\n\n"; copyText += assumptions; navigator.clipboard.writeText(copyText).then(function() { // Success feedback (optional) var btn = event.target; btn.textContent = 'Copied!'; setTimeout(function() { btn.textContent = 'Copy Results'; }, 2000); }, function(err) { console.error('Could not copy text: ', err); alert('Failed to copy results. Please copy manually.'); }); } function toggleFaq(element) { var parent = element.parentElement; parent.classList.toggle('open'); } // Initial calculation on page load document.addEventListener('DOMContentLoaded', function() { calculateWeightLoss(); // Add Chart.js script dynamically if not present if (typeof Chart === 'undefined') { var script = document.createElement('script'); script.src = 'https://cdn.jsdelivr.net/npm/chart.js@3.7.1/dist/chart.min.js'; // Use a specific, reliable CDN version script.onload = function() { updateChart(); // Update chart after chart.js is loaded }; document.head.appendChild(script); } else { updateChart(); // Update chart if Chart.js is already loaded } });

Leave a Comment