Body Fat Calculator
Estimate your body fat percentage using the U.S. Navy method from body measurements, instantly in your browser.
How to use the Body Fat Calculator
- Select your gender.
- Enter your height in centimeters.
- Measure and enter your neck circumference just below the larynx.
- Measure and enter your waist circumference: at the navel for men, at the narrowest point for women.
- Women: also enter hip circumference at the widest point. Then click Run to see your estimated body fat percentage.
How the Body Fat Calculator works
The U.S. Navy method estimates body fat from circumference measurements, because fat tends to accumulate around the waist (and hips in women) while the neck stays relatively lean. The formulas use base-10 logarithms of the measurements in centimeters:
Men: 495 ÷ (1.0324 − 0.19077 × log(waist − neck) + 0.15456 × log(height)) − 450Women: 495 ÷ (1.29579 − 0.35004 × log(waist + hip − neck) + 0.22100 × log(height)) − 450
It is typically accurate to within a few percentage points for most people, which makes it useful for tracking changes over time. For a precise measurement, clinical methods such as DEXA scans are more reliable.
Frequently asked questions
- Is this body fat calculator free?
- Yes. Estimate body fat percentage at no cost, with no account required.
- What method is used?
- The U.S. Navy circumference method, which estimates body fat from neck, waist, and (for females) hip measurements relative to height.
- How accurate is this estimate?
- The U.S. Navy method is a reasonably accurate estimate for most people but is not as precise as clinical methods like DEXA scans.