Calorie Deficit Calculator
Find out how many calories to eat per day to reach your goal weight safely and sustainably.
Frequently Asked Questions
What is a calorie deficit?
A calorie deficit means eating fewer calories than your body burns. When you consistently eat in a deficit, your body uses stored fat for energy, resulting in weight loss. A deficit of 500 calories per day typically produces about 0.5 kg (1 lb) of fat loss per week.
What's the minimum calories I should eat?
Most health professionals recommend not going below 1,200 calories/day for women or 1,500 for men without medical supervision. Very low calorie diets can cause muscle loss, nutrient deficiencies, and metabolic adaptation.
How fast can I safely lose weight?
A safe rate of weight loss is 0.5-1 kg (1-2 lbs) per week. Faster rates increase the risk of muscle loss, gallstones, and metabolic slowdown. Slower, consistent progress is more sustainable long-term.
Why is protein important during a deficit?
High protein intake (1.8-2.2g per kg body weight) during a calorie deficit helps preserve muscle mass, increases satiety, and has a higher thermic effect — your body burns more calories digesting protein than carbs or fat.
The science of calorie deficits
Weight loss comes down to energy balance: when you consume fewer calories than you burn, your body taps into stored energy (fat) to make up the difference. One kilogram of body fat contains approximately 7,700 calories, so a daily deficit of 500 calories produces roughly 0.5 kg of fat loss per week.
Why protein matters: During a calorie deficit, your body can break down muscle for energy alongside fat. Eating adequate protein (1.8-2.2g per kg body weight) and resistance training are the two most effective strategies to preserve muscle mass during weight loss.
Minimum calorie intake: This calculator enforces a floor of 1,200 calories per day. Going below this without medical supervision can lead to nutrient deficiencies, hormonal disruption, and metabolic adaptation that makes future weight loss harder.
This calculator provides estimates based on averages. Actual results vary based on metabolism, body composition, adherence, and other factors. Consult a healthcare provider before starting any weight loss program.