What is the Body Fat Percentage Calculator?

The body fat percentage calculator calculates a rough estimate of your future body fat percentage after a determined number of weeks on a diet. 

How does the Body Fat Percentage Calculator work?

Here are the 5 easy steps the calculator uses to determine your future body fat percentage.

Keep in mind, body fat is different from body weight. Body fat measures only the amount of fats in pounds excluding water, muscles, and others. All of which determined the body weight.

1- Body fat before diet (in pounds) = current weight X body fat percentage.

2- Body fat lost after diet (in pounds) = body fat loss per week X Number of weeks.

3- Bodyweight after weeks of diet (in pounds) = body weight before diet – Body fat before the diet.

4- Current Body Fat (in pounds) = body fat before diet – body fat loss after the diet. 

5- Body Fat percentage after the diet (%) = Current Body Fat / Bodyweight after weeks of diet X 100.

Once you figure out your body fat percentage, determine which category you belong to from this table below.


Female body fat %

Male body fat %

Essential fat

10 - 13%

2 - 5%


14 - 20%

6 - 13%


21 - 24%

14 - 17%


25 - 31%

18 - 25%


> 31%

> 25%

Note that the essential fat category is not taken into consideration in the calculator.