BMR stands for Basal Metabolic Rate. It is the amount of energy expended while at rest in a neutral environment. In other words, it is the amount of energy your body needs to function while you are not doing anything. This includes breathing, blood circulation, cell production, nutrient processing, and more. It is the minimum amount of energy your body needs to function. To get a more accurate estimate of your daily caloric needs, you can use the TDEE calculator.