This BMR calculator provides an estimate of your Basal Metabolic Rate (BMR). Your BMR is the the amount of calories that you burn while you are at complete rest and not digesting any food. In other words, BMR represents the amount of calories your body must burn to simply keep itself alive without accomplishing anything else. BMR calories are burned to sustain the function of vital organs like your heart, brain, nervous system, lungs, kidneys, liver, muscles, and skin, but BMR does not include calories burned to support physical activity or digestion of food.
This calculator is based on the widely used and accepted Harris-Benedict equations for BMR. They are shown below:
- Male (metric): BMR = (13.75 x WKG) + (5 x HC) - (6.76 x age) + 66
- Male (imperial): BMR = (6.25 x WP) + (12.7 x HI) - (6.76 x age) + 66
- Female (metric): BMR = (9.56 x WKG) + (1.85 x HC) - 4.68 x age) + 655
- Female (imperial): BMR = (4.35 x WP) + (4.7 x HI) - 4.68 x age) + 655
HC = Height in Centimetres
HI = Height in Inches
WKG = Weight in Kilograms
WP = Weight in Pounds
The equations above are exactly the same as those used for our Daily Caloric Expenditure Calculator, except that the "Activity Level Factor" that is used for the Daily Caloric Expenditure Calculator has been removed here. In the Daily Caloric Expenditure Calculator, BMR was multiplied by the "Activity Level Factor" to account for daily physical activity levels and the thermic effect of food (thereby providing an estimate of the total amount of calories you burn in a day), but these factors are not a consideration when determining BMR. The difference between the equations shown above and those on the Daily Caloric Expenditure Calculator is illustrative of the actual meaning of BMR.
Harris JA and Benedict FG. A Biometric Study of Human Basal Metabolism. Proc Natl Acad Sci U S A. 1918 December; 4(12): 370–373.