Body fat calculator
Estimate your body fat percentage from simple tape measurements using the U.S. Navy method.
What is body fat percentage?
Body fat percentage is the share of your total body weight that's made up of fat, as opposed to muscle, bone, organs, and water. Unlike weight or BMI, it describes what your body is actually made of — which is why two people can weigh exactly the same, share the same BMI, and still look and perform very differently depending on their body fat percentage.
Why body fat % matters more than weight alone
The number on a scale can't distinguish between losing fat and losing muscle, and it can't tell you whether a "healthy" weight is hiding a high body fat percentage — a pattern sometimes called "skinny fat." Tracking body fat percentage over time gives you a much clearer signal of whether a training or nutrition plan is actually working, especially when body weight itself barely moves.
Essential fat vs. storage fat
Not all body fat is the same. Essential fat — the minimum shown in the "Essential fat" row below — cushions organs and supports hormone production; going below it isn't a fitness goal, it's a health risk. Everything above that baseline is storage fat, which is what training and nutrition changes actually move.
Body fat categories
| Category | Men | Women |
|---|---|---|
| Essential fat | 2–5% | 10–13% |
| Athletes | 6–13% | 14–20% |
| Fitness | 14–17% | 21–24% |
| Average | 18–24% | 25–31% |
| Obese | 25%+ | 32%+ |
Frequently asked questions
How does the U.S. Navy body fat method work?
It estimates body fat percentage from circumference measurements — neck, waist, and height for men, plus hip for women — using a formula developed by the U.S. Navy as a fast alternative to skinfold calipers or DEXA scans.
How accurate is this method?
It is typically accurate within about 3–4% body fat compared to hydrostatic weighing, which makes it far more practical than lab methods while still being reasonably reliable for tracking progress over time.
Where exactly should I measure?
Neck: just below the larynx. Waist: at the navel for men, at the narrowest point for women. Hip (women only): at the widest point. Height: without shoes. Use a flexible tape and keep it snug but not compressing the skin.
How is body fat % different from BMI?
BMI only looks at weight relative to height, so it can't tell fat from muscle. Body fat percentage measures body composition directly, which is why two people with the same BMI can have very different body fat percentages depending on how much muscle they carry.
What is a healthy body fat percentage for men vs. women?
Women naturally carry more essential fat than men — roughly 10–13% versus 2–5% — because of hormonal and reproductive function. That gap carries through every category: a body fat percentage that's "average" for a woman would be "athletic" for a man, so always compare against your own sex's ranges, not a single universal number.
How often should I re-measure my body fat?
Every 2–4 weeks is plenty. Body composition changes slowly, and measuring more often mostly captures water retention and measurement noise rather than real change. Keep the tape at the same spots and time of day for consistency.
Can I estimate body fat without a tape measure?
Not reliably with this method — the Navy formula is built entirely from circumference measurements, so it needs a flexible tape. Smart scales (bioelectrical impedance) are a tape-free alternative, though they tend to be less consistent day-to-day than tape measurements taken carefully.