Calorie Deficit Calculator

A calorie deficit is the foundation of sustainable weight loss. This calculator estimates your Basal Metabolic Rate (BMR) using the Mifflin-St Jeor equation, then multiplies by your activity factor to get Total Daily Energy Expenditure (TDEE). By subtracting a safe deficit based on your chosen weekly goal, you get a personalised daily calorie target.

Why is this important? A deficit of 500–1000 calories per day typically leads to 0.5–1 kg of fat loss per week, which is recommended by health professionals. Crash diets with extreme deficits often backfire – they slow metabolism and reduce muscle mass. Our tool ensures you stay within healthy boundaries: we never recommend fewer than 1200 kcal/day for women or 1500 kcal/day for men without professional supervision.

To get the most accurate numbers, use your current weight and be honest about your activity level. Remember that these are estimates; individual metabolism can vary. Always combine your calorie goals with nutritious food and regular exercise. The numbers shown (BMR, TDEE, and deficit range) help you make informed decisions. If you’re pregnant, breastfeeding, or have metabolic conditions, consult a doctor before starting any diet.

We update our formulas regularly to reflect the latest research. The tool also adapts if you’re sedentary or highly active. Use it as a daily starting point, and adjust based on your hunger, energy, and progress. Weight loss is not linear – celebrate every step!