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 below the larynx, waist at the navel, hips at the widest point. The method is an estimate, measure carefully and the same way each time so changes you track are real.
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
Measured carefully, the method usually lands within a few percent of costlier scans like DEXA. It is an estimate, not a clinical reading, so measure at the right spots with the tape snug but not compressing.
Example
A man at 180 cm with a 38 cm neck and 85 cm waist estimates around 15% body fat.
Sources & methodology
- NIH, Assessing Your Weight and Health Risk, Body composition and health risk
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?
For most people it lands within a few percent of more expensive methods like DEXA, as long as you measure carefully at the right spots. It is an estimate, not a clinical reading.
Where do I measure?
Neck just below the larynx, waist at the navel, and hips at the widest point, all 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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