Body Fat Calculator
Estimate body fat percentage using the U.S. Navy method.
Inputs
Allowed range: 50 to 272
Allowed range: 10 to 100
Allowed range: 10 to 300
Allowed range: 10 to 300
Results
How it works
Uses circumference measurements. For men: 86.010·log10(waist−neck) − 70.041·log10(height) + 36.76. For women add hip and use a different formula.
Complete guide
Body fat percentage tells you how much of your body weight is fat versus lean tissue (muscle, bone, organs, water). It's a far better measure of health and fitness than BMI, which can't tell muscle from fat.
The U.S. Navy method uses simple tape-measure circumferences and is accurate to within ~3% for most people — far cheaper than DEXA scans or hydrostatic weighing. Measure neck just below the larynx, waist at the navel, and (for women) hip at the widest point. Stand relaxed, exhale normally, don't pull the tape tight.
General reference ranges for adults — men: 6–13% athletes, 14–17% fit, 18–24% average, 25%+ high. Women: 14–20% athletes, 21–24% fit, 25–31% average, 32%+ high. Women naturally carry more essential body fat than men.
Frequently asked questions
- How accurate is the Navy method?
- Within about 3% of clinical methods like DEXA when measurements are taken correctly. It's the best free at-home estimate available.
- How often should I measure?
- Every 2–4 weeks. Daily fluctuations are mostly water, not fat. Measure at the same time of day under similar conditions.
- Why do I need different formulas for men and women?
- Body fat distribution differs significantly by sex. Women's formula adds hip circumference because more fat is stored in the hip and thigh region.
- What's a healthy minimum body fat?
- Around 3–5% for men and 10–13% for women is considered essential — going below that risks hormonal and immune problems.