Total Metabolic Rate for Adults
The formula for basal metabolic rate uses variables such as your gender, height, weight and age to predict the speed at which you burn calories when at rest. It does not take into account your body fat composition. In reality a person of heavy muscular build would have a higher BMR than a person of the same weight who was just carrying more fat. The body requires an additional 16 calories daily for each pound of lean muscle, or 35 calories per kilogram. The difference in the formulae for men and women is mainly due to the different amounts of fat tissue in the male and female anatomy.
To compute your daily energy needs you also need to take into account your activity level using the Harris-Benedict formula. This multiplies the BMR by a factor to take into account activity, for example 1.2 for a sedentary person, up to a factor of two or more for an athlete. As lifestyles have changed, a slightly more accurate formula proposed by Mifflin has replaced the Harris-Benedict formula for BMR.
These figures are approximate and are dependent on other factors. They are only intended as a guide to your daily energy needs.