Body Fat Calculator (US Navy Method)
Estimates body fat from a few tape measurements.
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The formula
men: 495 ÷ (1.0324 − 0.19077 log(waist − neck) + 0.15456 log(height)) − 450 women: 495 ÷ (1.29579 − 0.35004 log(waist + hip − neck) + 0.22100 log(height)) − 450
Measurements are in centimetres and the logs are base 10.
What to watch out for
The equations come from Hodgdon and Beckett’s 1984 work for the US Navy. Measure against the skin without pulling the tape tight, and take each one two or three times.
Categories are from the American Council on Exercise. Men: essential 2–5%, athletes 6–13%, fitness 14–17%, average 18–24%, obese 25% or more. Women: essential 10–13%, athletes 14–20%, fitness 21–24%, average 25–31%, obese 32% or more.
Frequently Asked Questions
What would a 178 cm man with a 38 cm neck and 90 cm waist read?
About 20.1%.
How accurate is the Navy method?
It is a tape-based estimate, usually within a few percentage points of laboratory methods for most adults. Changes in the same person over time can be more useful than one reading.
What is a healthy body fat percentage?
There is no single agreed figure. The ACE average range is 18–24% for men and 25–31% for women, and it does not allow for age.