Your Basal Metabolic Rate (BMR) is the number of calories you burn as your body performs basic (basal) life-sustaining function.The average BMR for women is around 1400 kcal and about 1700 kcal for men, she says. Even if you and your workout buddy are the same age, sex, height, weight, and body composition, you still can have different BMRs. Things totally out of your control, like genetics and even organ size, impact BMR.