Body Composition
US Navy formula for women
The female equation adds the hip to the circumference term and uses a higher base, because the reference population stores fat differently.
The Formula
BF% = 495 / (1.29579 - 0.35004 x log(waist + hip - neck) + 0.22100 x log(height)) - 450
The female equation adds the hip to the circumference term and uses a higher base, because the reference population stores fat differently.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| waist + hip - neck | Combined hip and abdominal girth net of neck size | centimetres | For a 90 cm waist, 95 cm hip and 38 cm neck this is 147, whose base-10 logarithm is 2.167317334748176. |
| height | Standing height | centimetres | For 180 cm the base-10 logarithm is 2.255272505103306, the same as in the male form. |
| BF% | Estimated body fat percentage | percent | For the worked case this is 28.003411029161384%. |
What Each Symbol Means
waist + hip - neckcentimetres
Combined hip and abdominal girth net of neck size
For a 90 cm waist, 95 cm hip and 38 cm neck this is 147, whose base-10 logarithm is 2.167317334748176.
heightcentimetres
Standing height
For 180 cm the base-10 logarithm is 2.255272505103306, the same as in the male form.
BF%percent
Estimated body fat percentage
For the worked case this is 28.003411029161384%.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate body fat percentage page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Calculate Body Fat Percentage, filed under Health. Every number the guide produces comes from substituting into this one line.