The Mifflin St. Jeor BMR formula uses the variables of height, weight, age and gender to calculate the Basal Metabolic Rate (BMR). The only factor it omits is lean body mass. Because leaner bodies need more calories than less lean ones, this equation will be less accurate for the very muscular (it will underestimate calorie needs) and the very fat (it will over-estimate calorie needs).
The Katch-McArdle BMR formula is based only on lean body mass. This formula is thought to be the most accurate for people who are not fat or obese.
These calculators are meant to provide information, but cannot provide more than a rough estimate of your lean body mass and daily calorie needs. alifeinharmony.me is not responsible for your use of this information. Use at your own risk. Your personal health care professionals are the best source of guidance for health and diet information specific to you.