Basal metabolic rate (BMR), and the closely related resting metabolic rate (RMR), is the amount of daily energy expended while at rest in a neutrally temperate environment, in the post-absorptive state (meaning that the digestive system is inactive, which requires about twelve hours of fasting in humans).
The release of energy in this state is sufficient only for the functioning of the vital organs, the heart, lungs, nervous system, kidneys, liver, intestine, sex organs, muscles, and skin. - www.wikipedia.com
Men: = 66 + ( 6.23 x weight in lbs ) + ( 12.7 x height in inches ) – ( 6.8 x age in years)
Women: = 655 + ( 4.35 x weight in lbs ) + ( 4.7 x height in inches ) – ( 4.7 x age in years)
The Harris Benedict Equation is a formula that uses your BMR and then applies an activity factor to determine your total daily energy expenditure (calories). The only factor omitted by the Harris Benedict Equation is lean body mass.
Remember, leaner bodies need more calories than less leaner ones. Therefore, this equation will be very accurate in all but the very muscular (will under-estimate calorie needs) and the very fat (will over-estimate calorie needs). - www.bmi-calculator.com
Sedentary (little or no exercise) : Calorie-Calculation = BMR x 1.2
Lightly active (light exercise/sports 1-3 days/week) : Calorie-Calculation = BMR x 1.375
Moderately active (moderate exercise/sports 3-5 days/week) : Calorie-Calculation = BMR x 1.55
Very active (hard exercise/sports 6-7 days a week) : Calorie-Calculation = BMR x 1.725
Extra active (very hard exercise/sports & physical job or 2x training) : Calorie-Calculation = BMR x 1.9