Body Fat Calculator – Navy Method

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Use this calculator to figure out your body fat percentage. Body fat percentage is simply the percentage of fat that your body contains. For your body to function properly it is essential that your body contains a certain amount of fat. The percentage of essential body fat for women is greater than that for men, due to the demands of childbearing and other hormonal functions. The percentage of essential fat is 3–5% in men, and 10-16% in women.

The amount of body fat that you do or do not have can be potentially dangerous to your health. Carrying too much body fat can increase your risk of developing serious health problems such as high blood pressure, high cholesterol, heart disease, diabetes, and cancer. Too little body fat deprives your body of stored energy.

Your body fat percentage is calculated by taking your height and weight, gender, waist, wrist and forearm measurements into account, as well as hip measurements for women.

Use body fat calculator below to determine your body fat percentage easily. Your results will help you determine a healthy and realistic weight loss goal based on the information you provide.

How to measure neck, waist and hip circumference
Our body fat calculator needs four of your measurements: height, neck, waist, and hips, to determine the percentage and mass of body fat. Here is how to take the measurements, using a soft measurement tape:

Height: step on a flat surface that is perpendicular to a wall, column or a door frame. Look straight ahead. Get an assistant to place a ruler or another straight object on the top of your head so it is horizontal and mark the point at which it touches the wall, column, etc. Step out and measure the height from that point to the floor.
Neck: measure just inferior to the larynx with sloping slightly downward to the front (narrowest point).
Waist: measure at the widest point of the abdomen, at the level of your naval (umbilicus).
Hips: measure your hips at the widest point below your waist, while keeping your feet together for an accurate measurement.

You can use both centimeters and inches to record the measurement, since our body fat calculator supports both units. Accuracy to the nearest half inch or within 1 cm should be sufficient.

It is recommended that you wear minimal clothing during the measurement. It is also recommended to have your measures taken by an assistant, since if you are taking them yourself you will not be fully relaxed and may be twisting your body and skewing the results.

How to calculate body fat using the U.S. Navy Method
In calculating body fat, we use the method developed for the United States Navy Force in the second half of the 20-th century. It is essentially a formula that can be used to calculate an estimate of your body fat based on simple body measurements. The standard error of the estimate is ~3.5 percent points in either direction [2], meaning that about 68% of estimated body fat percentages will fall within ±3.5 of the true BFP, while ~95% of estimated BFPs will fall within ±7 of it.

For men, SI metrics (centimeters), the formula is [3]:

100 x ((4.95 / (1.0324 – 0.19077 * log10(waist – neck) + 0.15456 * log10(height))) – 4.5)

For women, SI metrics (centimeters), the formula is [4]:

100 x ((4.95 / (1.29579 – 0.35004 * log10(waist + hip – neck) + 0.22100 * log10(height))) – 4.5)

For imperial metrics (inches) high-precision conversions are performed automatically by our body fat percentage calculator.

Is my body fat percentage normal?
The American Council on Exercise Body Fat Categorization is presented in the table below:

Body Fat Categorization
Category Women Men
Essential fat 10-13% 2-5%
Athletes 14-20% 6-13%
Fitness 21-24% 14-17%
Average 25-31% 18-25%
Obese 32%+ 25%+
The above are, of course, averages, so the normal body fat percentage may vary depending on your health condition, level and type of physical activity, and others.

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