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How to Calculate Body Fat Percentage

Do this every week and keep records, the best time to use this formula, is in the morning. Your body weight and waist measurements are the most accurate just after you wake up from 7-8 hours of sleep.  

  • After you awake, go the bathroom, if you have to, then use the formula below.

The formula below will give you a good estimate of your body fat percentage. This formula should also give you a consistent measurement you can use as a guideline so you can determine if you're losing body fat and or muscle. You can also use it for gaining weight, of course for weight gain, you want to be sure your gains are muscle and not fat.

Not good at math? use our automated Body Fat Analizer

Men

The Formula

An Example

   
Step One  
Your total body weight  200 total body weight
(times)  x 1.082  x  1.082
(plus)  + 94.420  =  216.4
(equals)  =  Factor 1  + 94.420
   = 310.82 (factor 1)
Step Two  
Your waist measurement (at naval)   36 inch waist measurement
(times)  x 4.150  x 4.150
(equals)  = Factor 2  = 149.40 (factor 2)
   
Step Three  
Factor 1   310.82
(minus)  - Factor 2  - 149.40
(equals)  = Lean Body Weight  = 161.42 (lean body weight)
   
Step Four  
Your total body weight   200  total body weight
(minus)  - Lean Body Weight  - 161.42  lean body weight
(equals)  = Body Fat Weight = 38.58 lbs. body fat weight
   
Step Five  
Body Fat lbs.   38.58 lbs. body fat
(times)  x 100  x 100
(divide)  ÷ Your total body weight  = 3858
(equals)  = Body Fat Percentage  ÷ 200 total body weight
  = 19.29 % body fat percent level

 

Women

The Formula

An Example

   
Step One  
Your total body weight  140 total body weight
(times) x .732  x .732
(plus) + 8.987  = 102.48
(equals) =  Factor 1  + 8.987
   = 111.467 (factor 1)
Step Two   
Your wrist measurement (fullest point) Not your forearm  6.30 inch wrist measurement
(divide) ÷ 3.140  ÷ 3.140
(equals) = Factor 2  = 2.006 (factor 2)
   
Step Three  
Abdominal Measurement (at naval)  28 inch abdominal measurement
(times)  x 0.157  x 0.157
(equals) = Factor 3  = 4.396 (factor 3)
   
Step Four  
Hip measurement (at fullest point)  39 inch hip measurement
(times) x 0.249  x 0.249
(equals) = Factor 4  9.711 (factor 4)
   
Step Five  
Forearm measurement (fullest point)  11 inch forearm measurement
(times) x 0.434  x 0.434
(equals) = factor 5  = 4.774 (factor 5)
   
Step Six  
Factor 1  111.467 (factor 1)
(plus) factor 2  + 2.006 (factor 2)
(minus) factor 3  = 113.473
(minus) factor 4   - 4.396 (factor 3)
(plus) factor 5  = 109.077
(equals) Lean Body Mass  - 9.711 (factor 4)
   = 99.366
   + 4.774 (factor 5)
   = 104.14 Lean body weight
Step Seven   
Total bodyweight  140 lbs. total body weight
(minus) lean bodyweight  - 104.14 lean body weight
(equals) Body Fat weight  = 35.86 lbs. body fat weight
   
Step Eight  
body fat weight  35.86 lbs. body fat weight
(times) 100  x 100
(divide) ÷ total bodyweight  = 3586
(equals) body fat percentage  ÷ 140 lbs. total body weight
   = 25.614 % body fat 

Body fat targets:

  • Men
     
    Athletes:  - 6% to 14%.
      None Athletes: 10% to 22%
  • Women
      Athletes:- 12% to 28%
      None Athletes: 16% to 32%

NOTE: These recommendations may vary depending on your age, body type etc.