0.25 kg (0.5 lbs)
0.5 kg (1 lb)
0.75 kg (1.5 lbs)
1 kg (2.2 lbs)
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 or training)
Understanding Your Daily Calorie Goal for Weight Loss
Losing weight sustainably involves creating a calorie deficit, meaning you consume fewer calories than your body burns. This calculator helps you estimate your daily calorie intake to achieve your desired weight loss rate. The core principle is that approximately 7,700 calories equal one kilogram of body fat.
How the Calculator Works:
This calculator uses a multi-step process to estimate your daily calorie target:
Basal Metabolic Rate (BMR): This is the number of calories your body burns at rest to maintain basic life functions (breathing, circulation, cell production). While this calculator doesn't directly ask for height and weight to calculate BMR using Harris-Benedict or Mifflin-St Jeor equations, it uses your Current Weight and Activity Level to estimate your Total Daily Energy Expenditure (TDEE), which is closely related to BMR.
Total Daily Energy Expenditure (TDEE): This is an estimation of the total number of calories you burn in a 24-hour period. It accounts for your BMR and your physical activity level. A higher activity level means a higher TDEE. The calculator uses your Activity Level multiplier to estimate this.
Calorie Deficit for Weight Loss: To lose weight, you need to consume fewer calories than your TDEE. The calculator determines the daily calorie deficit required to meet your Desired Weekly Weight Loss.
1 kg of fat is roughly equivalent to 7,700 calories.
Therefore, to lose 'X' kg per week, you need a weekly deficit of X * 7,700 calories.
The daily deficit is (X * 7,700) / 7 calories.
Daily Calorie Target: Your estimated daily calorie target is calculated by subtracting the required daily deficit from your estimated TDEE.
Daily Calorie Target = TDEE – Daily Deficit
Important Considerations:
Individual Variability: Calorie expenditure and metabolism vary greatly from person to person. This calculator provides an estimate, not an exact science. Factors like age, sex, muscle mass, and genetics play a significant role.
Safe Weight Loss: A sustainable and healthy rate of weight loss is typically 0.5 kg to 1 kg (1-2 lbs) per week. Rapid weight loss can be detrimental to health and is often unsustainable.
Nutrition Quality: Focus on nutrient-dense foods (lean proteins, vegetables, fruits, whole grains) to ensure you're getting essential vitamins and minerals even when reducing calories.
Consult a Professional: For personalized advice and a comprehensive weight management plan, it is always recommended to consult with a doctor, registered dietitian, or certified nutritionist.
function calculateCalories() {
var currentWeight = parseFloat(document.getElementById("currentWeight").value);
var goalWeight = parseFloat(document.getElementById("goalWeight").value);
var weightLossRate = parseFloat(document.getElementById("weightLossRate").value);
var activityLevel = parseFloat(document.getElementById("activityLevel").value);
var resultDiv = document.getElementById("result");
if (isNaN(currentWeight) || isNaN(goalWeight) || isNaN(weightLossRate) || isNaN(activityLevel)) {
resultDiv.innerHTML = "Please enter valid numbers for all fields.";
return;
}
if (currentWeight <= goalWeight) {
resultDiv.innerHTML = "Your goal weight should be less than your current weight to lose weight.";
return;
}
if (currentWeight <= 0 || goalWeight <= 0 || weightLossRate <= 0) {
resultDiv.innerHTML = "Weight values and loss rate must be positive.";
return;
}
// Estimate TDEE (Total Daily Energy Expenditure)
// This is a simplified approach. A more accurate TDEE would involve calculating BMR first (e.g., using Mifflin-St Jeor or Harris-Benedict equation which requires height, age, and gender).
// Here, we're directly scaling based on weight and activity level.
// A common multiplier for BMR is around 10-12 kcal/kg of body weight.
// TDEE = BMR * Activity Factor. We'll use a simplified TDEE estimation for demonstration.
var estimatedBmrPerKg = 22; // An average estimate in kcal/kg/day for adults
var estimatedBmr = currentWeight * estimatedBmrPerKg;
var tdee = estimatedBmr * activityLevel;
// Calculate required daily calorie deficit
var caloriesPerKgFat = 7700;
var weeklyDeficit = weightLossRate * caloriesPerKgFat;
var dailyDeficit = weeklyDeficit / 7;
// Calculate target daily calorie intake
var targetCalories = tdee – dailyDeficit;
// Display the result
resultDiv.innerHTML = "Estimated Daily Calorie Goal: " + Math.round(targetCalories) + " calories";
resultDiv.style.backgroundColor = "var(–success-green)";
}