Estimate your body fat percentage using the U.S. Navy circumference method, with lean mass and category breakdown.
| Category | Men | Women |
|---|---|---|
| Essential Fat | 2–5% | 10–13% |
| Athletic | 6–13% | 14–20% |
| Fitness | 14–17% | 21–24% |
| Average | 18–24% | 25–31% |
| Obese | 25%+ | 32%+ |
Select your unit system and sex, then enter your height, weight, age, and circumference measurements (neck and waist for men; neck, waist, and hip for women). The calculator uses the U.S. Navy method to estimate your body fat percentage, along with your fat mass, lean mass, and category classification.
Measure your neck just below the larynx (Adam's apple), keeping the tape slightly downward-sloping. Measure your waist at the navel for the most consistent results, and for women, measure your hips at the widest point. Use a flexible tape measure and keep it snug but not compressing the skin, ideally measuring first thing in the morning before eating.
The U.S. Navy circumference method was developed and validated by the U.S. military as a practical field alternative to skinfold calipers and DEXA scans. While not as precise as lab-grade methods like hydrostatic weighing or DEXA, it correlates reasonably well with more expensive techniques and only requires a tape measure, making it one of the most accessible reliable estimation methods available.
The Navy method typically estimates body fat within 3–4% of more precise methods like DEXA scans for most people, which is comparable to skinfold calipers used correctly. It tends to be less accurate for very lean athletes or people with atypical body fat distribution, but it remains one of the most accessible and reasonably reliable home methods available.
The Navy method formula was derived separately for men and women based on where each sex typically stores fat. Men's formula uses neck and waist only, since male fat storage correlates more strongly with abdominal circumference. Women's formula adds hip measurement since female fat storage and distribution is better predicted by including hip circumference.
For men, 14–17% is generally considered "fitness" level and 18–24% is "average" and still healthy. For women, 21–24% is "fitness" level and 25–31% is "average" and healthy. Athletes often sit lower, but going too far below the essential fat range (2–5% men, 10–13% women) can be harmful to hormonal and organ function.