Tthe percentage of body fat using the U.S. Navy Circumference Method.

Measurements should be done so that the tape measure fits snugly but does not compress the skin.

   
How to Measure

Height - measured without shoes
Weight - taken in the morning without clothes after going to the bathroom and before eating or drinking anything
Waist (Men) - measure horizontally, at the level of the navel
(Women) - measure horizontally, at the level of minimal abdominal width
Neck - measure below the larynx with the tape sloping slightly downward to the front.
Hips (Women only) - Largest horizontal circumference around the hips


Enter your height, weight, and other information, then click the "Calculate" button.
  English Units Metric Units
Height   feet      inches     centimeters  
Weight  pounds    kilograms    
Waist  inches    centimeters  
Neck  inches    centimeters  
 Hips (Female)   inches    centimeters  
Sex Male       Female
Level
of
Activity
sedentary   Passive activities:
Watching TV, working on the computer, reading, driving a car 
moderate  Lively activities:
One hour per day walking, swimming, jogging, tennis 
active Vigorous activities:
Two hours or more per day moving furniture or playing sports 
Body Mass Index:    
Waist-to-Height ratio:    
Percent Body Fat:    
Lean Body Mass:    

 
 

 

What do the numbers mean?

Body Mass Index (BMI) - The BMI is the ratio of your weight to the square of your height. People with a BMI 25 or greater are considered overweight, unless they have a very muscular body. If your BMI is 25 or greater, and your Waist-to-Height ratio is less than 0.5 and your Percent Body Fat is in the "athlete" or "fitness" category, you are probably muscular and not fat.

Underweight BMI less than 18.5
Normal weight BMI 18.5 to 24.9
Overweight BMI 25 to 29.9
Obese BMI 30 or greater



Waist-to-Height Ratio - The Waist-to-Height ratio is determined by dividing the waist circumference by the height. Waist-to-Height ratios of 0.5 or greater are indicative of intra-abdominal fat for both men and women and are associated with a greater risk of cardiovascular disease. A study found that persons with a normal BMI but a large waist circumference, corresponding approximately to a Waist-to-Height ratio of 0.55, had a 20% higher mortality risk than persons with a normal waist size.

Percent Body Fat - The percent body fat is calculated using the formulas developed by Hodgdon and Beckett at the Naval Health Research Center in 1984. The formulas require the measurements to be in centimeters with an accuracy of 0.5 cm. However, the form above has been adjusted to accept measurements in inches. Men and women require different methods for measuring because men accumulate fat mostly in the abdomen (the "apple" body shape or "beer belly"), while women accumulate fat in their abdomen and hips (the "pear" body shape). The equations take this into consideration. The American Council on Exercise uses the following categories based on percentage of body fat:

  Women Men
Essential fat    10-12% 2-4%
Athletes 14-20% 6-13%
Fitness 21-24% 14-17%
Acceptable 25-31% 18-25%
Obese 32% or more 26% or more

Lean Body Mass or Fat-Free Mass - This is derived by subtracting the calculated value of body fat from the total weight. Lean Body Mass = Weight × (100 - %BodyFat)

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