How to Calculate Lean Body Mass

Waist measurement

Lean body mass is the mass of the body minus the fat. This is good information to know if you are concerned with your overall health, how you look and how you feel. The percentage of fat on your body can have direct implications on some health risks, such as Type 2 diabetes, heart disease, high blood pressure, stroke, sleep apnea, osteoarthritis and cancer. The information below explains how to calculate your lean body mass and your percentage of body fat without investing in specialized equipment.

Difficulty:

Moderately Easy

Instructions

Things You'll Need

• Fabric measuring tape Scale

1. Weigh yourself and record your weight in pounds.

2. Measure your waist at the navel and record it below your weight in pounds.

3. Plug the measurements into the formula below:

   For Women:
   [(4.15 x waist measurement) -- (0.082 x weight) -- 76.76] / weight

   For Men:
   [(4.15 x waist measurement) -- (0.082 x weight) -- 98.42] / weight

   The result is your percentage of body fat.

4. Take the result from above and multiply it by your weight. This will yield your body fat in pounds.

5. Subtract your body fat in pounds from your total weight to get your lean body mass.

   Here is an example. A woman weighs 130 pounds and has a 27 inch waist.

   [(4.15 x 27) -- (0.082 x 130) -- 76.76] / 130

   [112.05 -- 10.66 -- 76.76] / 130

   24.63 / 130 = .1895 (body fat percentage)

   Multiply this by total weight (0.1895 x 130) = 24.63 pounds of fat

   To get lean body mass subtract 24.63 from 130 = 105.37

Tips & Warnings

• This method is usually accurate within 1 to 3 percentage points.

Resources

• American Medical Association