CalcKitHow to Use the Calorie Calculator
Your body burns calories all day — even while you sleep. A calorie calculator estimates how many calories you need each day using two well-known numbers: your BMR (Basal Metabolic Rate), the energy you burn at complete rest, and your TDEE (Total Daily Energy Expenditure), which adds your activity on top of BMR.
This calculator uses the Mifflin-St Jeor equation, the formula most dietitians consider the most accurate for the general population. Enter your age, gender, height, weight and activity level, choose your goal, and press Calculate Calories. You'll get your BMR, your maintenance calories, and your daily target for losing, maintaining or gaining weight.
The maths behind weight change is simple: a daily deficit of about 500 kcal typically leads to roughly 0.5 kg of fat loss per week, while a 500 kcal surplus leads to similar gain. That's why the "lose weight" goal subtracts 500 kcal from your maintenance number.
Treat the result as a starting point, not a prescription. Metabolism varies with muscle mass, hormones, medical conditions and even sleep. Track your weight for two to three weeks at the target intake and adjust up or down by 100–200 kcal if you're not moving toward your goal — and check your BMI alongside for the full picture.