Free Calorie Deficit Calculator App

Calorie Deficit Calculator

Use this calculator to estimate your Basal Metabolic Rate (BMR), Total Daily Energy Expenditure (TDEE), and the daily calorie intake needed to achieve your weight loss goals through a calorie deficit.

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)
0.5 kg (approx. 1.1 lbs) per week 1 kg (approx. 2.2 lbs) per week 1 lb (approx. 0.45 kg) per week 2 lbs (approx. 0.9 kg) per week

Understanding Calorie Deficit for Weight Loss

A calorie deficit is the cornerstone of weight loss. It occurs when you consistently consume fewer calories than your body burns. When your body doesn't get enough energy from food, it starts to use stored fat for fuel, leading to a reduction in body weight.

How Your Body Burns Calories

Your body burns calories in three main ways:

  1. Basal Metabolic Rate (BMR): This is the number of calories your body needs to perform basic, life-sustaining functions like breathing, circulation, cell production, and nutrient processing while at rest. It accounts for the largest portion of your daily calorie expenditure.
  2. Thermic Effect of Food (TEF): This is the energy your body uses to digest, absorb, and metabolize the food you eat. It typically accounts for about 10% of your total calorie intake.
  3. Activity Energy Expenditure (AEE): This includes all calories burned during physical activity, from structured exercise to non-exercise activity thermogenesis (NEAT) like walking, fidgeting, and standing.

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, combining your BMR, TEF, and AEE. Our calculator uses the Mifflin-St Jeor equation to estimate your BMR, which is then multiplied by an activity factor to determine your TDEE. This provides a more accurate estimate than simply using BMR alone.

Creating a Calorie Deficit

To lose weight, you need to create a consistent calorie deficit. A common guideline is that a deficit of 3,500 calories is roughly equivalent to losing one pound of body fat. Therefore, to lose 1 pound per week, you would aim for a daily deficit of 500 calories (3500 calories / 7 days).

  • Moderate Deficit (500-750 calories/day): This typically leads to a healthy and sustainable weight loss of 1-1.5 pounds (0.5-0.7 kg) per week.
  • Larger Deficit (750-1000+ calories/day): Can lead to faster weight loss (1.5-2+ pounds or 0.7-1+ kg per week), but may be harder to sustain and could risk muscle loss if not managed properly with adequate protein intake and strength training.

How to Use This Calculator

Simply input your age, gender, current weight, height, and select your typical activity level. Then, choose your desired weekly weight loss target. The calculator will provide you with:

  • Your estimated Basal Metabolic Rate (BMR).
  • Your estimated Total Daily Energy Expenditure (TDEE).
  • The daily calorie deficit required to meet your goal.
  • Your target daily calorie intake for weight loss.

Important Considerations

While this calculator provides a useful estimate, individual results can vary. Factors like genetics, body composition, hormonal balance, and metabolic adaptations can influence your actual calorie needs. Always prioritize a balanced diet rich in whole foods, adequate protein, and regular physical activity. For personalized advice, especially if you have underlying health conditions or significant weight loss goals, consult with a healthcare professional or a registered dietitian.

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padding: 12px 15px; } } function updateUnitLabels() { var unitsMetric = document.getElementById('unitsMetric').checked; if (unitsMetric) { document.getElementById('weightUnit').innerText = 'kg'; document.getElementById('heightUnit').innerText = 'cm'; document.getElementById('weight').value = '70'; // Default metric weight document.getElementById('height').value = '175'; // Default metric height // Update target loss options to show kg first document.getElementById('targetLoss').innerHTML = ` 0.5 kg (approx. 1.1 lbs) per week 1 kg (approx. 2.2 lbs) per week 1 lb (approx. 0.45 kg) per week 2 lbs (approx. 0.9 kg) per week `; } else { document.getElementById('weightUnit').innerText = 'lbs'; document.getElementById('heightUnit').innerText = 'inches'; document.getElementById('weight').value = '154'; // Default imperial weight (70kg) document.getElementById('height').value = '69'; // Default imperial height (175cm) // Update target loss options to show lbs first document.getElementById('targetLoss').innerHTML = ` 1 lb (approx. 0.45 kg) per week 2 lbs (approx. 0.9 kg) per week 0.5 kg (approx. 1.1 lbs) per week 1 kg (approx. 2.2 lbs) per week `; } } function calculateCalorieDeficit() { var age = parseFloat(document.getElementById('age').value); var gender = document.getElementById('gender').value; var weight = parseFloat(document.getElementById('weight').value); var height = parseFloat(document.getElementById('height').value); var activityLevel = document.getElementById('activityLevel').value; var targetLoss = document.getElementById('targetLoss').value; var unitsMetric = document.getElementById('unitsMetric').checked; var resultDiv = document.getElementById('result'); resultDiv.innerHTML = "; // Clear previous results // Input validation if (isNaN(age) || age <= 0 || isNaN(weight) || weight <= 0 || isNaN(height) || height <= 0) { resultDiv.innerHTML = 'Please enter valid positive numbers for age, weight, and height.'; return; } var weightKg = weight; var heightCm = height; // Convert to metric if imperial units are selected if (!unitsMetric) { weightKg = weight * 0.453592; // lbs to kg heightCm = height * 2.54; // inches to cm } // Mifflin-St Jeor Equation for BMR var bmr; if (gender === 'male') { bmr = (10 * weightKg) + (6.25 * heightCm) – (5 * age) + 5; } else { // female bmr = (10 * weightKg) + (6.25 * heightCm) – (5 * age) – 161; } // Activity Factors var activityFactor; switch (activityLevel) { case 'sedentary': activityFactor = 1.2; break; case 'lightlyActive': activityFactor = 1.375; break; case 'moderatelyActive': activityFactor = 1.55; break; case 'veryActive': activityFactor = 1.725; break; case 'extraActive': activityFactor = 1.9; break; default: activityFactor = 1.2; // Default to sedentary } var tdee = bmr * activityFactor; // Daily calorie deficit for target weight loss var dailyDeficitNeeded; var targetLossText = ''; switch (targetLoss) { case '0.5kg': dailyDeficitNeeded = 550; // Approx. for 0.5 kg/week (7700 kcal/kg / 14 days) targetLossText = '0.5 kg (approx. 1.1 lbs) per week'; break; case '1kg': dailyDeficitNeeded = 1100; // Approx. for 1 kg/week (7700 kcal/kg / 7 days) targetLossText = '1 kg (approx. 2.2 lbs) per week'; break; case '0.5lb': dailyDeficitNeeded = 500; // Approx. for 1 lb/week (3500 kcal/lb / 7 days) targetLossText = '1 lb (approx. 0.45 kg) per week'; break; case '1lb': dailyDeficitNeeded = 1000; // Approx. for 2 lbs/week (3500 kcal/lb * 2 / 7 days) targetLossText = '2 lbs (approx. 0.9 kg) per week'; break; default: dailyDeficitNeeded = 500; // Default to 1 lb/week targetLossText = '1 lb (approx. 0.45 kg) per week'; } var targetDailyCalories = tdee – dailyDeficitNeeded; // Display results resultDiv.innerHTML = ` Your estimated Basal Metabolic Rate (BMR): ${Math.round(bmr)} calories/day Your estimated Total Daily Energy Expenditure (TDEE): ${Math.round(tdee)} calories/day To achieve a weight loss of ${targetLossText}, you need a daily calorie deficit of approximately ${Math.round(dailyDeficitNeeded)} calories. Your target daily calorie intake for weight loss: ${Math.round(targetDailyCalories)} calories/day Note: These are estimates. Individual needs may vary. Consult a healthcare professional for personalized advice. `; } // Initialize unit labels on page load document.addEventListener('DOMContentLoaded', function() { updateUnitLabels(); });

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