About the Body Fat Percent Calculator
The body fat percentage is a measure of fitness level, since it is a body measurement which directly calculates a person's relative body composition without regard to height or weight.
The body fat percentage has different interpretations according to gender, because the female body composition has naturally a higher fat content.
The American Council on Exercise suggests these ranges for classifying individuals based on the body fat percentage:
| Classification | Female | Male |
| Essential fat (underweight) | 10-13% | 3-5% |
| Athletic | 14-20% | 6-13% |
| Fit | 21-24% | 14-17% |
| Overweight | 25-31% | 18-24% |
| Obese | >31% | >24% |
Calculation
Body fat percentage is very difficult to measure directly but there are some good estimation methods based on:
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Underwater weighing
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Whole-body air displacement
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Near-infrared interactance
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Dual energy X-ray absorptiometry
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Body average density measurement
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Bioelectrical impedance analysis
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Anthropometric methods
This calculator uses an Anthropometric method developed by the US Department of Defense in 1984 that has proven to be a reasonably accurate way to estimate body fat based on some body proportions.
The formula for BF estimation in our calculator is:
BF% = 163.205 x log10(waist + hips – neck) – 97.684 x log10(height) – 78.387 (women)
BF% = 86.010 x log10(waist – neck) – 70.041 x log10(height) + 36.76 (men)
All units in these formulas should be in inches. You can use our calculator in metric units that the conversion to imperial units is taken into account.
Waist The total perimeter of the waist. For women it should be measured at the smallest portion of the waist, for men it should be measured slightly above the belly button.
Neck The total perimeter of the neck at it smallest point.
Hips This value is not relevant for man body fat estimation. For women it should be measured at the largest part of the buttocks.
For more info on body fat percentage: https://en.wikipedia.org/wiki/Body_fat_percentage