Find your Total Daily Energy Expenditure and exact calorie targets for weight loss, maintenance, and muscle gain — using the clinically validated Mifflin-St Jeor equation.
Your daily calorie need is your TDEE — Total Daily Energy Expenditure. It's calculated by multiplying your BMR (Basal Metabolic Rate, the calories your body burns at rest) by an activity multiplier based on how much you exercise.
This calculator uses the Mifflin-St Jeor equation, validated as the most accurate for most people by the American Dietetic Association:
A deficit of 500 calories/day produces approximately 0.5 kg (1 lb) of fat loss per week — a safe, sustainable rate. Deficits above 1,000 calories/day risk muscle loss, nutrient deficiency, and metabolic adaptation. Never go below 1,200 kcal/day (women) or 1,500 kcal/day (men) without medical supervision.
Protein (4 kcal/gram) is the most satiating macronutrient and is essential for preserving muscle during a calorie deficit. Research consistently supports 1.6–2.2 g per kg of bodyweight for active individuals. Higher intakes (up to 3 g/kg) are safe and can aid fat loss by increasing satiety.
BMR is the minimum calories your body needs to survive — breathing, circulation, cell repair. You burn those calories even lying completely still. TDEE adds the calories burned through movement, digestion (the thermic effect of food, ~10% of TDEE), and daily activity. TDEE is what you actually need to eat to maintain your weight.
The Mifflin-St Jeor equation is accurate within ~10% for most people. Activity multipliers introduce additional uncertainty — people often overestimate their activity level. If your weight isn't changing after 2–3 weeks at a calculated calorie target, adjust by ±100–200 calories and reassess. The calculator gives a strong starting point; real-world tracking refines it.
At a 500 calorie/day deficit: ~0.5 kg (1 lb) per week. At a 250 calorie/day deficit: ~0.25 kg (0.5 lb) per week. Weight loss is rarely perfectly linear — water retention, hormonal changes, and glycogen stores cause week-to-week variation. Focus on the 4-week trend, not daily weigh-ins.