How to measure
- Use a flexible tape measure on bare skin, standing relaxed. Do not pull in your stomach.
- Neck: just below the larynx (Adam's apple), with the tape sloping slightly down at the front.
- Waist: men at the level of the navel; women at the narrowest point of the waist.
- Hips (women): around the widest part of the buttocks.
- Measure each twice and use the average. Measure at the same time of day each time you track progress.
The US Navy formula
Men: %BF = 86.010 × log₁₀(waist − neck) − 70.041 × log₁₀(height) + 36.76
Women: %BF = 163.205 × log₁₀(waist + hip − neck) − 97.684 × log₁₀(height) − 78.387
All measurements are in inches. The calculator converts centimetres for you.
Worked example: a man 70 in (178 cm) tall with a 34 in waist and 15 in neck: 86.010 × log₁₀(19) − 70.041 × log₁₀(70) + 36.76 = 17.5%, in the "fitness" range.
Body fat ranges
| Category | Men | Women |
|---|---|---|
| Essential fat | 2–5% | 10–13% |
| Athletes | 6–13% | 14–20% |
| Fitness | 14–17% | 21–24% |
| Average | 18–24% | 25–31% |
| Above average | 25% and over | 32% and over |
Ranges from the American Council on Exercise. Women naturally carry more essential fat than men.
Accuracy: tape-measure methods are usually within about 3–4 percentage points of laboratory methods such as DEXA, and are most useful for tracking change over time with the same tape and technique.
Sources
- Hodgdon JA, Beckett MB. Prediction of percent body fat for US Navy men and women from body circumferences and height. Naval Health Research Center, 1984
- US Department of Defense Instruction 1308.03, body composition programme
- American Council on Exercise, body fat percentage norms
Frequently asked questions
How accurate is the US Navy body fat method?
For most people it is within about 3–4 percentage points of laboratory methods. Careful, consistent measuring matters more than anything else.
What is a healthy body fat percentage?
Roughly 14–24% for men and 21–31% for women covers the fitness and average ranges used by the American Council on Exercise.
Why do women need hip measurements?
Women store more fat around the hips, so the women's formula uses waist plus hips minus neck to estimate body fat more accurately.
Is body fat percentage better than BMI?
It tells you more about body composition, because it separates fat from lean mass. BMI is quicker but cannot tell muscle from fat.