Simple Resting Metabolism (Weight Formula) Calculator View Calculator Your resting metabolism (RMR) (also known as basal metabolism or BRM) is the minimum calories you burn each day for your body to keep everything functioning. The simplest RMR formula, used by this calculator, requires just gender and weight. This formula was developed by Dr. Fred Hatfield of the International Sports Sciences Association and is fairly accurate if your body fat is in the normal range (14-19% for men, 20-25% for women). If your body fat is substantially higher than normal, this formula will overestimate your RMR. Learn more about putting this calculator or other calculators on your website.