BMR is the amount of energy your body burns at rest. Body fatness is calculated from your body fatness.
Try using one of the many website that have a BMR calculator. Calculating your BMR uses your body size and age, and tells your how many calories your body needs to function each day. Also, see the related external link further down this page.
the important of calculating your bmr is to see the body fat
fat mass
I'm assuming you mean Basal Metabolic Rate (BMR). Most conventional formulas to estimate BMR use your current weight, height, and age. With that, current weight and height increase your BMR while age decreases it. Other factors include lean body mass (increase) and gender (males typically have a higher BMR).
Metabolism is worked out using BMR. BMR stands for your basal metabolic rate. This is the amount of cals you burn doing nothing, just allowing your body to run. The larger you are (weight or height) the higher your BMR will be. The older you are the lower your BMR will be due to muscle loss year on year. If you have a lot of muscle compared to fat your BMR will be higher.
Metabolism. Basic Metabolic Rate (BMR)
You need your age, height and weight to calculate it. I linked an article in the "Related Links" section that explains what BMR is and how it effects your weight. It also, of course, explains how to calculate it.
It is healthy because it reduces the fatness and upgrades you body
Body weight, height, and age
By definition, measuring BMR requires the body to be in an established and maintained state of rest. The conditions set for its measurement ensure this state.
BMR is dictated by the set point. For example, if you were to go on a very low calorie diet, your body would lower its metabolic set point. Therefore, the BMR would be focused on conserving energy and storing those calories.
body size, temperature, sex, level of endocrine gland activity