Calculator Weight Loss

Weight Loss Goal Calculator

Use this calculator to estimate your Basal Metabolic Rate (BMR), Total Daily Energy Expenditure (TDEE), and the time it might take to reach your target weight based on your desired weekly weight loss.

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)
(Recommended: 0.5 – 2 lbs per week for sustainable loss)

Understanding Your Weight Loss Journey

Achieving a healthy weight involves understanding your body's energy needs and creating a sustainable calorie deficit. This calculator helps you estimate key metrics for your weight loss journey.

Basal Metabolic Rate (BMR)

Your Basal Metabolic Rate (BMR) is the number of calories your body needs to perform basic, life-sustaining functions while at rest. This includes breathing, circulation, cell production, nutrient processing, and organ function. It's the minimum amount of energy required to keep you alive.

The calculator uses the Mifflin-St Jeor equation, which is widely considered one of the most accurate BMR formulas:

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

Total Daily Energy Expenditure (TDEE)

Your Total Daily Energy Expenditure (TDEE) is the total number of calories your body burns in a 24-hour period, including your BMR and the calories burned during physical activity. It's a more accurate representation of your daily calorie needs.

TDEE is calculated by multiplying your BMR by an activity factor:

  • Sedentary: BMR × 1.2 (little or no exercise)
  • Lightly Active: BMR × 1.375 (light exercise/sports 1-3 days/week)
  • Moderately Active: BMR × 1.55 (moderate exercise/sports 3-5 days/week)
  • Very Active: BMR × 1.725 (hard exercise/sports 6-7 days a week)
  • Extra Active: BMR × 1.9 (very hard exercise/physical job)

Calorie Deficit for Weight Loss

To lose weight, you need to consume fewer calories than your body burns. This is known as creating a calorie deficit. Approximately 3,500 calories equals one pound of body fat. Therefore, to lose one pound per week, you generally need a daily calorie deficit of 500 calories (3500 calories / 7 days).

This calculator helps you determine the daily calorie intake needed to achieve your desired weekly weight loss.

Sustainable Weight Loss

While it might be tempting to aim for rapid weight loss, a healthy and sustainable rate is typically 0.5 to 2 pounds per week. Losing weight too quickly can lead to muscle loss, nutritional deficiencies, and may be harder to maintain long-term. Always consult with a healthcare professional or a registered dietitian before making significant changes to your diet or exercise routine.

Example Calculation:

Let's consider a 30-year-old moderately active male, 5'10" (177.8 cm) and 180 lbs (81.65 kg), aiming to lose 1.5 lbs per week.

  • BMR: (10 * 81.65) + (6.25 * 177.8) – (5 * 30) + 5 = 816.5 + 1111.25 – 150 + 5 = 1782.75 calories
  • TDEE: 1782.75 * 1.55 (Moderately Active) = 2763.26 calories
  • Desired Weekly Loss: 1.5 lbs
  • Daily Calorie Deficit: (1.5 lbs * 3500 calories/lb) / 7 days = 525 calories
  • Target Daily Calorie Intake: 2763.26 – 525 = 2238.26 calories
  • Weight to Lose: If target is 150 lbs, then 180 – 150 = 30 lbs
  • Total Calories to Deficit: 30 lbs * 3500 calories/lb = 105,000 calories
  • Estimated Days to Target: 105,000 / 525 = 200 days
  • Estimated Weeks to Target: 200 days / 7 days/week = 28 weeks and 4 days

This example demonstrates how the calculator provides a personalized estimate to guide your weight loss efforts.

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Daily calorie deficit is zero or negative. Please ensure desired weekly loss is positive.'; return; } var estimatedWeeks = Math.floor(estimatedDaysToTarget / 7); var remainingDays = Math.round(estimatedDaysToTarget % 7); resultDiv.innerHTML = 'Your estimated Basal Metabolic Rate (BMR): ' + bmr.toFixed(0) + ' calories/day' + 'Your estimated Total Daily Energy Expenditure (TDEE): ' + tdee.toFixed(0) + ' calories/day' + 'To achieve a ' + desiredWeeklyLossLbs.toFixed(1) + ' lb weekly loss, you need a daily calorie deficit of approximately ' + dailyCalorieDeficit.toFixed(0) + ' calories.' + 'Your target daily calorie intake for weight loss: ' + targetDailyCalorieIntake.toFixed(0) + ' calories/day' + 'Estimated time to reach your target weight of ' + targetWeightLbs.toFixed(1) + ' lbs: ' + estimatedWeeks + ' weeks and ' + remainingDays + ' days'; if (targetDailyCalorieIntake < 1200 && gender === 'female') { resultDiv.innerHTML += 'Warning: A daily calorie intake below 1200 calories for women is generally not recommended without medical supervision.'; } else if (targetDailyCalorieIntake < 1500 && gender === 'male') { resultDiv.innerHTML += 'Warning: A daily calorie intake below 1500 calories for men is generally not recommended without medical supervision.'; } }

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