Calorie Deficit Calculator

How to use

1. Enter your current weight and desired goal weight in kg.
2. Input your Total Daily Energy Expenditure (TDEE).
3. Select your preferred deficit pace: mild (-300 kcal), optimal (-500 kcal), or aggressive (-750 kcal).
4. Review your daily calorie target.
5. View the projected completion date and estimated weekly fat loss rate.

What is a calorie deficit and how fat loss works

A calorie deficit occurs when your total energy expenditure exceeds dietary energy intake. In response, adipose cells release stored triglycerides to fuel baseline cellular operations and physical motion.

One kilogram of human body fat stores roughly 7,700 kcal of metabolized energy. Burning 1 kg of adipose mass requires generating a 7,700 kcal cumulative energy deficit.

Selecting an optimal caloric reduction rate

• Mild (-300 kcal/day): ~0.27 kg/week loss. Maximum satiety, optimal for body recomposition and preserving strength.
• Optimal (-500 kcal/day): ~0.45–0.5 kg/week loss. The clinical gold standard for sustainable, hunger-free fat loss.
• Aggressive (-750 kcal/day): ~0.7 kg/week loss. Best suited for individuals with higher initial BMI under supervision.

The physiological hazards of severe caloric restriction (>1000 kcal)

• Adaptive thermogenesis: downregulation of thyroid conversion blunts non-exercise movement and baseline BMR.
• Lean mass catabolism: severe deficits compel the body to strip muscle tissue via gluconeogenesis.
• Elevated cortisol: drives stubborn water retention and uncontrollable binge-eating impulses.

Macronutrient targets during caloric restriction

• Protein: 1.6 to 2.2 g per kg of body mass to maximize muscle retention and satiety signaling.
• Dietary Fats: minimum 0.8 g per kg to ensure hormonal equilibrium and fat-soluble vitamin absorption.
• Carbohydrates: complex starches, legumes, and high-fiber veggies to maintain athletic performance.