Estimate your daily calorie needs to maintain, lose, or gain weight, based on your activity level.
This uses the Mifflin-St Jeor equation to estimate your basal metabolic rate (BMR) — the calories your body burns at rest — then multiplies it by an activity factor to estimate your total daily energy expenditure (TDEE). A pound of body weight is roughly 3,500 calories, so the loss/gain estimates adjust your maintenance number up or down accordingly.
This is a helpful starting estimate, not a medical calculation — actual needs vary by individual metabolism, body composition, and health conditions.