A BMR (Basal Metabolic Rate) Calculator helps you estimate the number of calories your body burns at rest to maintain vital functions such as breathing, circulation, and cell repair. Knowing your BMR is the first step in understanding how many calories you need daily to maintain, lose, or gain weight. By combining your BMR with your activity level, you can calculate your TDEE (Total Daily Energy Expenditure), which gives a clearer picture of your actual calorie requirements.