Calorie Deficit Calculator

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Gender

Age

Height (cm)

Current Weight (kg)

Goal Weight (kg)

Activity Level

Weight Loss Rate

How Calorie Deficit Works

Weight loss fundamentally comes down to energy balance. When you consistently consume fewer calories than your body burns, it must draw on stored energy — primarily body fat — to make up the difference. One kilogram of body fat contains approximately 7,700 calories, so a daily deficit of 550 calories leads to roughly 0.5 kg of fat loss per week.

Setting the Right Deficit

🐢 Slow (250 cal/day)

Best for those close to goal weight. Minimal muscle loss, easy to maintain.

⚖️ Moderate (500 cal/day)

Gold standard for most people. 0.5 kg/week loss with good adherence.

🚀 Fast (750 cal/day)

For those with significant weight to lose. Requires careful macro tracking.

⚠️ Aggressive (1000+ cal/day)

Only under medical supervision. High risk of muscle loss and metabolic adaptation.

Frequently Asked Questions

A calorie deficit occurs when you consume fewer calories than your body burns. This forces your body to use stored energy (fat) for fuel, resulting in weight loss.

A deficit of 500 calories/day (leading to ~0.5 kg/week loss) is generally recommended for sustainable weight loss. Larger deficits can lead to muscle loss, metabolic slowdown, and nutrient deficiencies.

Eating below your BMR can trigger metabolic adaptation, where your body slows its metabolism to conserve energy. This makes future weight loss harder and can cause hormonal disruptions, muscle loss, and fatigue.

Healthy weight loss is 0.5-1 kg per week. To lose 10 kg, expect 10-20 weeks. Faster rates are possible but increase the risk of muscle loss and metabolic slowdown.

Partially. If your TDEE already accounts for exercise via activity level, you don't need to eat back exercise calories. If you do additional unplanned exercise, eating back 50-75% of those calories helps prevent excessive deficit.

Disclaimer: This calculator is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult with a qualified healthcare provider before making health decisions.