Body Fat Calculator
Estimate your body-fat percentage with the U.S. Navy circumference method, just a tape measure for neck, waist, and (for women) hips. Shows your fitness category. Calculates in your browser.
Body fat
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Show the math
The U.S. Navy method estimates body fat from tape measurements and height:
men use neck & waist
women add the hip measurement
Measure relaxed with the tape snug: neck just below the larynx; men's waist at the navel; women's waist at its narrowest, about midway between the bottom of the breastbone and the navel; hips at the widest point of the buttocks. The method is an estimate: studies against DEXA scans find average differences of a few percentage points and much bigger ones for some people, so measure the same way each time and watch the trend.
What this does
A body fat calculator estimates your body-fat percentage with the U.S. Navy circumference method (using a tape measure for your neck, waist and, for women, hips) and shows your fitness category.
How to use it
- Enter your height and sex.
- Measure and enter your neck and waist (plus hips for women).
- Read your estimated body-fat percentage.
- See the fitness category it falls in.
How it works
The Navy regression equations relate the circumferences of your neck and waist (plus hips for women) to your height to estimate body fat. It needs only a tape measure and no special equipment.
Understanding your result
It is an estimate, not a clinical reading. Studies comparing it with DEXA scans find average differences of a few percentage points, and much larger ones for some people (it tends to read lean people high and higher body fat low), so measure at the right spots, the same way each time, and watch the trend.
Example
A man at 180 cm with a 38 cm neck and 85 cm waist estimates about 16% body fat.
Sources & methodology
- NIH, Assessing Your Weight and Health Risk, Body composition and health risk
- American Council on Exercise, Percent Body Fat Norms for Men and Women, Category bands: essential fat, athletes, fitness, acceptable, obesity
Last updated .
Frequently asked questions
How does the Navy method work?
It estimates body fat from the circumferences of your neck and waist (plus hips for women) relative to your height, using the Navy regression equations. It needs only a tape measure.
How accurate is it?
On average it lands a few percentage points from a DEXA scan, but for some people the gap is much bigger. It is an estimate, not a clinical reading, so use it to track change over time.
Where do I measure?
Neck just below the larynx. Men: waist at the navel. Women: waist at its narrowest, about midway between the bottom of the breastbone and the navel, and hips at the widest point of the buttocks. Stand relaxed, with the tape snug but not compressing the skin.
Are my measurements stored?
No. Everything is computed locally in your browser.
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