Calorie Calculator

Calculate exactly how many calories you need per day to lose weight, maintain, or gain muscle. Based on the Mifflin-St Jeor equation.

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How Many Calories Do You Need Per Day?

Daily calorie needs vary widely based on age, sex, body size, activity level, and goal. The average adult needs roughly 1,800–2,500 calories per day to maintain weight, but this range masks enormous individual variation. Using a personalised calculation based on your specific measurements is far more accurate than using population averages.

Calories for Weight Loss

A deficit of 500 calories per day below your maintenance level produces a theoretical loss of roughly 0.5 kg per week. In practice, the body adapts over time, so progress may slow after 4–6 weeks. Cycling your intake, taking diet breaks, and gradually increasing activity helps overcome plateaus.

Calories for Muscle Gain

A modest surplus of 200–300 calories above maintenance provides the energy needed for muscle repair and growth while minimising excess fat gain. Larger surpluses (500+ calories) result in faster weight gain but a higher proportion as fat for most people.

Frequently Asked Questions

Should I eat fewer than 1,200 calories to lose weight faster?
Very low calorie diets (<1,200 kcal for women, <1,500 for men) are not recommended without medical supervision. They accelerate muscle loss, slow metabolism, and are difficult to sustain.
Do I need to count calories to lose weight?
Not strictly. Focusing on food quality, protein intake, and eating patterns can achieve a natural calorie reduction. However, tracking calories even temporarily can dramatically improve awareness of intake.
Why am I not losing weight at my calculated deficit?
Common reasons include underestimating food intake, overestimating activity, water retention, or metabolic adaptation. Consider re-measuring your activity level or speaking with a dietitian.
Medical Disclaimer: This calculator is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional for health decisions.