I tried out your calculator two different ways knowing my body fat composition (I was measured on a body fat scale at my gym). On the first trial I entered data using my body fat percentage, which had been measured to be 6%. I weigh 87 pounds and the calculator told me this weight was within healthy range for me. Considering the fact that I am 5 feet 3 inches tall, I know many doctors and nurses who have very recently told me I need to gain weight. (By the way, I am a recovered anorexic and I think your calculator could give people like myself the wrong idea!!!) I entered the data on a second trial without entering my body fat percentage and it said I am underweight. Well, which is it? You tell me!

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    You are correct and this bug had been fixed.

    Glad you are hearing your doctors and nurses. You are underweight. Your healthy body weight, irrelative of body fat, is 103 – 127. Bare minimum, you should weigh 103 pounds.

    With regards to a body fat scale reading, depending on your hydration and whether or not you are menstruating, 6% may or may not be accurate. Please read info in sports nutrition topic regarding measuring body fat and inherent errors of various testing methods.