Estimate how many calories your body burns in a day so you can eat to match your goal. Enter your age, sex, height, weight and activity level, and the calculator first works out your basal metabolic rate using the well-regarded Mifflin-St Jeor equation, then multiplies it by an activity factor to give your total daily energy expenditure (TDEE). That TDEE is roughly the calories needed to maintain your current weight. It then shows suggested targets for a moderate cut, maintenance, and a lean bulk, based on a standard calorie offset. These are starting estimates, not medical advice, and real results depend on many factors. All numbers are computed locally in your browser and nothing is stored.