The following formula is used by the army to calculate approximate body fat percentages:
\[ \%BF = (86.010 \times \log_{10}(waist - neck)) - (70.041 \times \log_{10}(height)) + 36.76 \]
Where:
An army body fat is a specific calculation for estimating body fat that is used in determining the suitability of a person for acceptance into the army.
Age 17 to 20: 20% for males, 30% for females
Age 21 to 27: 22% for males, 32% for females
Age 28 to 39: 24% for males, 34% for females
Age over 40: 26% for males, 36% for females
