Basal Metabolic Rate or BMR refers to the amount of energy or calories needed for vital bodily functions over a 24 hours period in a state of rest. An indirect rough estimation of ones BMR is calculated using the Mifflin St Jeor Equation.
P – Total heat production.
m – Mass or weight in KG.
h – Height in CM.
s – Sex or gender: +5 for men and −161 for women.
BMR for men = 10 x weight (kg) + 6.25 x height (cm) – 5 x age (years) + 5
BMR for women = 10 x weight (kg) + 6.25 x height (cm) – 5 x age (years) – 161
Basal Metabolic Rate accounts for 70% of the TDEE – Total Daily Energy Expenditure. The remaining 30% expenditure comes from physical activity (roughly 20%) and thermogenesis or digestion of food (about 10%).