The BSA (Body Surface Area) calculator is a tool used to estimate the total surface area of your body. It calculates this area based on the your height and weight. BIt's useful for calculating drug or supplement dosages, assessing burns, and for predicting metabolic rates.
These are only estimates and should not be taken as the end-all, be-all. Talk with your provider about steps you can take to get back on track if you aren't already.