Body mass index and daily calorie needs.
Body mass index and daily calorie needs.
BMI (Body Mass Index) is calculated as weight (kg) รท height (m)ยฒ. It classifies weight status as Underweight (<18.5), Normal weight (18.5โ24.9), Overweight (25โ29.9), or Obese (30+). BMI is a screening tool โ it doesn't account for muscle mass, bone density, or body fat distribution.
TDEE (Total Daily Energy Expenditure) estimates how many calories you need per day to maintain your current weight. This calculator uses the Mifflin-St Jeor BMR formula with a moderate activity multiplier (1.55ร). Adjust your actual calorie target based on your activity level.
The WHO defines 18.5โ24.9 as the normal weight range for adults. BMI of 25โ29.9 is overweight, and 30+ is obese. However, athletes often have a BMI in the overweight range due to high muscle mass, and BMI thresholds may differ for certain ethnic groups (e.g., lower thresholds apply in some Asian populations).
TDEE is your total daily calorie burn. To lose weight, eat below your TDEE (typically a 500 kcal/day deficit = ~1 lb/week loss). To gain muscle, eat slightly above TDEE (200โ300 kcal surplus). To maintain weight, match your calorie intake to TDEE. The figure here assumes moderate activity โ adjust up or down based on your actual exercise level.
BMR (Basal Metabolic Rate) is the calories your body needs at complete rest โ just to breathe and keep organs functioning. TDEE factors in your activity level by multiplying BMR by an activity factor. This calculator applies a moderate activity factor (1.55ร, roughly 3โ5 exercise sessions per week).