Body Fat Calculator
Estimate body fat percentage using the U.S. Navy method based on measurements.
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Quick Tip
Select your sex, since the formula differs.
About This Tool
Why use Body Fat Calculator?
This calculator estimates body fat percentage with the U.S. Navy method, which uses a tape measure rather than a scale. Men need height, neck and waist; women also need hip circumference, because fat distribution differs.
The method is accurate to roughly ±3% against more expensive techniques when the measurements are taken carefully, which makes it useful for tracking change over time. Measure at the same points each time: the neck just below the larynx, the waist at the navel, and the hips at their widest. Keep the tape level and snug without compressing the skin.
Key Benefits
Only a tape measure needed
No calipers, scales or gym equipment: circumferences are enough for the Navy formula.
Better than BMI for composition
Because it uses waist and neck rather than weight alone, it separates build from body fat far better than BMI does.
Category shown with the number
The percentage is placed into the usual essential, athletic, fitness, average and obese bands for your sex.
How to use Body Fat Calculator
- 1
Select your sex, since the formula differs.
- 2
Enter your height, then neck and waist circumference — and hips if you are female.
- 3
Read the estimated body fat percentage and its category.
- 4
Repeat under the same conditions (same time of day, same tape placement) when tracking progress.
Best use cases
Track fat loss during a training block when scale weight is flat.
Estimate body composition without a gym assessment.
Compare progress against the standard fitness categories.
Get a more meaningful figure than BMI if you lift weights regularly.
Body Fat Calculator FAQs
How accurate is the U.S. Navy body fat method?
Within roughly 3 percentage points of hydrostatic weighing for most people, provided measurements are taken consistently. It is less reliable at the extremes of body composition.
What is a healthy body fat percentage?
The American Council on Exercise lists 14–17% as fitness and 18–24% as average for men, and 21–24% fitness and 25–31% average for women. Essential fat is about 2–5% for men and 10–13% for women.
Where exactly should I measure?
Neck just below the larynx with the tape sloping slightly down at the front; waist at navel level for men and at the narrowest point for women; hips at the widest point. Stand relaxed and do not pull the tape tight.
Why do women need a hip measurement?
The Navy formula uses different equations by sex because fat is distributed differently. The women's version includes hip circumference to account for that.
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