Calculate Weight Loss

Weight Loss Goal Calculator

Estimate your Basal Metabolic Rate (BMR), Total Daily Energy Expenditure (TDEE), and the time it will take to reach your weight loss goal.

Male Female
Sedentary (little or 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/physical job)

Your Weight Loss Plan:

Basal Metabolic Rate (BMR): calories/day

Total Daily Energy Expenditure (TDEE): calories/day

Required Daily Calorie Deficit: calories/day

Target Daily Calorie Intake: calories/day

Estimated Time to Goal:

function calculateWeightLoss() { var currentWeightLbs = parseFloat(document.getElementById('currentWeightLbs').value); var targetWeightLbs = parseFloat(document.getElementById('targetWeightLbs').value); var heightInches = parseFloat(document.getElementById('heightInches').value); var ageYears = parseFloat(document.getElementById('ageYears').value); var gender = document.getElementById('genderSelect').value; var activityLevel = document.getElementById('activityLevelSelect').value; var weeklyWeightLossGoalLbs = parseFloat(document.getElementById('weeklyWeightLossGoalLbs').value); var resultContainer = document.getElementById('resultContainer'); var bmrResult = document.getElementById('bmrResult'); var tdeeResult = document.getElementById('tdeeResult'); var dailyCalorieDeficitResult = document.getElementById('dailyCalorieDeficitResult'); var targetDailyCaloriesResult = document.getElementById('targetDailyCaloriesResult'); var timeToGoalResult = document.getElementById('timeToGoalResult'); var warningMessage = document.getElementById('warningMessage'); warningMessage.innerHTML = "; // Clear previous warnings resultContainer.style.display = 'none'; // Hide results until valid calculation // Input validation if (isNaN(currentWeightLbs) || currentWeightLbs <= 0 || isNaN(targetWeightLbs) || targetWeightLbs <= 0 || isNaN(heightInches) || heightInches <= 0 || isNaN(ageYears) || ageYears <= 0 || isNaN(weeklyWeightLossGoalLbs) || weeklyWeightLossGoalLbs = currentWeightLbs) { warningMessage.innerHTML = 'Target Weight must be less than Current Weight.'; return; } // Convert to metric for BMR calculation (Mifflin-St Jeor) var currentWeightKg = currentWeightLbs * 0.453592; var heightCm = heightInches * 2.54; var bmr; if (gender === 'male') { bmr = (10 * currentWeightKg) + (6.25 * heightCm) – (5 * ageYears) + 5; } else { // female bmr = (10 * currentWeightKg) + (6.25 * heightCm) – (5 * ageYears) – 161; } var activityMultiplier; switch (activityLevel) { case 'sedentary': activityMultiplier = 1.2; break; case 'light': activityMultiplier = 1.375; break; case 'moderate': activityMultiplier = 1.55; break; case 'very': activityMultiplier = 1.725; break; case 'extra': activityMultiplier = 1.9; break; default: activityMultiplier = 1.2; // Default to sedentary } var tdee = bmr * activityMultiplier; // 1 lb of fat is approximately 3500 calories var dailyCalorieDeficit = (weeklyWeightLossGoalLbs * 3500) / 7; var targetDailyCalories = tdee – dailyCalorieDeficit; var totalWeightToLoseLbs = currentWeightLbs – targetWeightLbs; var weeksToGoal = totalWeightToLoseLbs / weeklyWeightLossGoalLbs; var monthsToGoal = weeksToGoal / 4.33; // Approximate weeks in a month var timeToGoalText = "; if (weeksToGoal < 4) { timeToGoalText = weeksToGoal.toFixed(1) + ' weeks'; } else { timeToGoalText = monthsToGoal.toFixed(1) + ' months (' + weeksToGoal.toFixed(1) + ' weeks)'; } // Display results bmrResult.innerHTML = bmr.toFixed(0); tdeeResult.innerHTML = tdee.toFixed(0); dailyCalorieDeficitResult.innerHTML = dailyCalorieDeficit.toFixed(0); targetDailyCaloriesResult.innerHTML = targetDailyCalories.toFixed(0); timeToGoalResult.innerHTML = timeToGoalText; resultContainer.style.display = 'block'; // Additional warnings if (targetDailyCalories < 1200 && gender === 'female') { warningMessage.innerHTML += ' Warning: Your target daily calorie intake is very low. It is generally not recommended for women to consume fewer than 1200 calories per day without medical supervision.'; } else if (targetDailyCalories 2) { warningMessage.innerHTML += ' Warning: A weekly weight loss goal of more than 2 lbs is often considered aggressive and may not be sustainable or healthy for everyone. Consult a healthcare professional.'; } } .weight-loss-calculator { font-family: Arial, sans-serif; max-width: 600px; margin: 20px auto; padding: 20px; border: 1px solid #ddd; border-radius: 8px; background-color: #f9f9f9; } .calculator-input-group { margin-bottom: 15px; } .calculator-input-group label { display: block; margin-bottom: 5px; font-weight: bold; } .calculator-input-group input[type="number"], .calculator-input-group select { width: calc(100% – 22px); /* Adjust for padding and border */ padding: 10px; border: 1px solid #ccc; border-radius: 4px; box-sizing: border-box; } button { background-color: #007bff; color: white; padding: 12px 20px; border: none; border-radius: 4px; cursor: pointer; font-size: 16px; width: 100%; box-sizing: border-box; } button:hover { background-color: #0056b3; } #resultContainer { background-color: #e9f7ef; border: 1px solid #d4edda; border-radius: 5px; padding: 15px; margin-top: 20px; } #resultContainer h3 { color: #28a745; margin-top: 0; } #resultContainer p { margin-bottom: 8px; line-height: 1.5; } #warningMessage { margin-top: 10px; font-weight: bold; }

Understanding Your Weight Loss Journey

Embarking on a weight loss journey can be a rewarding experience, but it often comes with questions about how much to eat, how much to exercise, and how long it will take to see results. Our Weight Loss Goal Calculator is designed to provide you with a personalized estimate, helping you set realistic expectations and understand the caloric requirements for achieving your target weight.

How the Calculator Works

This calculator uses established scientific formulas to estimate your body's energy needs and the calorie deficit required for weight loss. Here's a breakdown of the key metrics:

1. Basal Metabolic Rate (BMR)

Your Basal Metabolic Rate (BMR) is the number of calories your body burns at rest to maintain basic life-sustaining functions, such as breathing, circulation, and cell production. It's the minimum amount of energy your body needs to simply exist. The calculator uses the Mifflin-St Jeor Equation, which is widely considered one of the most accurate BMR formulas, taking into account your current weight, height, age, and gender.

  • 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

2. Total Daily Energy Expenditure (TDEE)

While BMR accounts for calories burned at rest, your Total Daily Energy Expenditure (TDEE) includes the calories you burn through all activities throughout the day, including exercise, work, and even digestion. The calculator multiplies your BMR by an activity factor based on your reported activity level:

  • Sedentary: Little or no exercise (BMR x 1.2)
  • Lightly Active: Light exercise/sports 1-3 days/week (BMR x 1.375)
  • Moderately Active: Moderate exercise/sports 3-5 days/week (BMR x 1.55)
  • Very Active: Hard exercise/sports 6-7 days a week (BMR x 1.725)
  • Extra Active: Very hard exercise, physical job, or training twice a day (BMR x 1.9)

Your TDEE is the approximate number of calories you need to consume daily to maintain your current weight.

3. Calorie Deficit for Weight Loss

To lose weight, you need to consume fewer calories than your body burns. This creates a "calorie deficit." It's generally accepted that a deficit of 3,500 calories is needed to lose one pound of body fat. The calculator determines the daily calorie deficit required to achieve your desired weekly weight loss goal.

4. Target Daily Calorie Intake

This is the estimated number of calories you should aim to consume daily to reach your weight loss goal. It's calculated by subtracting your required daily calorie deficit from your TDEE.

5. Estimated Time to Goal

Based on your total weight loss target and your desired weekly weight loss, the calculator provides an estimate of how many weeks or months it might take to reach your goal. This helps you visualize the timeline for your journey.

Realistic Weight Loss Expectations

While the calculator provides a useful estimate, it's crucial to approach weight loss with realistic expectations and a focus on sustainable habits. A healthy and sustainable rate of weight loss is typically considered to be 1-2 pounds per week. Losing weight too quickly can lead to muscle loss, nutritional deficiencies, and may be harder to maintain long-term.

Factors Affecting Weight Loss

Beyond calories in vs. calories out, many factors can influence your weight loss journey:

  • Diet Quality: Focusing on whole, unprocessed foods, lean proteins, healthy fats, and plenty of fruits and vegetables can improve satiety and nutrient intake.
  • Exercise: A combination of cardiovascular exercise and strength training is ideal for burning calories, building muscle (which boosts metabolism), and improving overall health.
  • Sleep: Lack of sleep can disrupt hormones that regulate appetite and metabolism, making weight loss more challenging.
  • Stress: Chronic stress can lead to increased cortisol levels, which may promote fat storage, especially around the abdomen.
  • Hydration: Drinking enough water can help with satiety and overall bodily functions.
  • Individual Metabolism: Everyone's metabolism is unique and can be influenced by genetics, hormones, and medical conditions.

Important Disclaimer

This calculator provides an estimate based on general formulas and should not be considered medical advice. Individual results may vary. Before making significant changes to your diet or exercise routine, especially if you have underlying health conditions, it is highly recommended to consult with a healthcare professional, registered dietitian, or certified personal trainer. They can provide personalized guidance tailored to your specific health needs and goals.

Example Scenario:

Let's say a 30-year-old male, 68 inches tall and weighing 180 lbs, wants to reach a target weight of 150 lbs. He considers himself moderately active and aims to lose 1 lb per week.

  • Current Weight: 180 lbs
  • Target Weight: 150 lbs
  • Height: 68 inches
  • Age: 30 years
  • Gender: Male
  • Activity Level: Moderately Active
  • Desired Weekly Weight Loss: 1 lb

Based on these inputs, the calculator would estimate:

  • BMR: Approximately 1751 calories/day
  • TDEE: Approximately 2714 calories/day
  • Required Daily Calorie Deficit: 500 calories/day (3500 calories/week for 1 lb loss / 7 days)
  • Target Daily Calorie Intake: Approximately 2214 calories/day (2714 – 500)
  • Estimated Time to Goal: 30 weeks or about 6.9 months.

This example demonstrates how the calculator provides actionable insights into the caloric adjustments needed and the potential timeline for achieving a weight loss goal.

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