Body Fat Calculator
Estimate body fat percentage, fat mass, and lean mass with the U.S. Navy circumference method.
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Estimate body fat percentage from circumference measurements
Body Fat Calculator uses height, weight, neck, waist, and hip measurements to estimate body fat percentage, fat mass, and lean mass with the U.S. Navy method. It helps track body composition trends beyond scale weight alone.
Useful For
- Estimate body fat from waist and neck measurements
- Check fat mass and lean mass references
- Track body composition changes during training
Good To Know
Circumference formulas are estimates and can vary with measurement position and posture. For medical decisions or athletic assessment, use professional tools and guidance.
Result Check
Try an example first to understand the input flow. Before submitting, sharing, or copying important output, compare the result with the original source once more.
How It Works
Inputs are calculated or converted in the browser whenever possible. Compare important results with the original source before using them. Reviewed on Jul 1, 2026.
Body fat estimate checks
Measure
- Measure neck, waist, and hip at a consistent time
- Keep the tape level and neither too tight nor too loose
Formula
- The U.S. Navy method is a circumference-based estimate
- It can differ from BIA, DEXA, or professional measurement
Use
- Track trends using the same method rather than over-focusing on one value
- Use medical or fitness professionals and real tests for health decisions
The estimate uses values such as sex, height, weight, neck, waist, and hip measurements.
Yes. Circumference-based formulas and body-composition devices use different methods and can produce different results.
No. It is a health reference tool. Medical conditions, athletic training, and weight management plans should be discussed with a professional.