How it’s worked out
The US Navy method was developed by Hodgdon and Beckett at the Naval Health Research Center in 1984 and is still used by the US armed forces. It estimates body fat from circumferences, all in inches:
Men: 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76 Women: 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387
Measurements typed in centimetres are converted to inches first, so both units give the same answer.
Worked examples
A man 70 in (178 cm) tall with a 15 in neck and 34 in waist: 17.5%. An inch more on the waist gives 19.4%. A woman 65 in tall with a 13 in neck, 30 in waist and 38 in hips: 28.6%.
How to read the result
- It is an estimate: against lab scans the tape method is usually within about 3–4 percentage points, so the page shows a likely range.
- Watch the trend: measured the same way, a change over months tells you more than one reading.
- With your weight it splits into fat mass and lean mass (everything else).
Common mistakes
- Measuring in the wrong place: men’s waist at the navel, women’s at the narrowest point, the neck just below the Adam’s apple.
- Pulling the tape tight or holding your breath in: keep it snug but flat, and breathe out normally.
- Measuring once: take each three times and type the average.
How to use it
- Choose the formula for men or women and type your height.
- Measure your neck and waist (and hips for women) and type them.
- Add your weight to see fat and lean mass.
Questions
How accurate is the US Navy body fat method?
For most adults it is within about 3–4 percentage points of a lab measurement. It is less reliable for very muscular people, children, older people and in pregnancy.
Where do I measure my waist?
For the men’s formula, level with the navel; for the women’s, at the narrowest point, usually just above the navel. Breathe out normally and keep the tape level.
Does this tell me what my body fat should be?
No. It gives an estimate only and no medical advice; talk to your doctor about what your figure means for you.
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Elsewhere on Yuzool
- BMI calculator in Figure
- Calorie calculator in Figure
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