Body Fat Calculator
Estimate your body fat percentage with the U.S. Navy tape method — just a few measurements give your body fat, category and lean body mass. Everything is worked out on your device; nothing is uploaded.
How the U.S. Navy body fat method works
The U.S. Navy method estimates body fat from body circumference measurements rather than skinfold calipers or a scan, which makes it easy to do at home with just a tape measure. For men it uses height, neck and waist; for women it also uses the hip measurement, because fat distribution differs. Those circumferences are combined in a logarithmic formula that correlates closely with body density, and the density is converted to a fat percentage.
For example, a man 178 cm tall with a 38 cm neck and an 85 cm waist comes out at about 16% body fat — in the fitness range. Because the method reacts to your waist and neck, it does a good job of tracking real changes as you lose fat or build muscle.
Healthy body fat ranges
Body fat needs differ by sex because women carry more essential fat. These are widely used categories from the American Council on Exercise:
| Category | Men | Women |
|---|---|---|
| Essential fat | 2–5% | 10–13% |
| Athletes | 6–13% | 14–20% |
| Fitness | 14–17% | 21–24% |
| Average | 18–24% | 25–31% |
| Above average | 25%+ | 32%+ |
Body fat vs BMI — why it matters
BMI uses only your height and weight, so a lean, muscular person can be labelled "overweight" even though they carry little fat. Body fat percentage estimates how much of your weight is actually fat, so it gives a clearer read on body composition. The two work well together: BMI as a quick screen, body fat for a truer picture.
How to measure accurately
Use a flexible tape and keep it level and snug without squeezing the skin. Measure the neck just below the voice box, sloping slightly down at the front; the waist at the navel for men and at the narrowest point for women; and the hips at the widest point. Measure on bare skin, breathe normally, and take each reading two or three times and average them. Measuring at the same time of day gives the most consistent tracking.
Limitations to keep in mind
Every field method is an estimate. The Navy formula is usually within about three to four percentage points of a DEXA scan for most people, but it can be less accurate for very muscular or very lean individuals, and it assumes a typical fat distribution. Treat the number as a useful benchmark to track over time, not an exact clinical measurement — the trend matters more than any single reading.
Frequently asked questions
How does the U.S. Navy body fat method work?
It estimates body fat from circumferences. Men use height, neck and waist; women add the hip. The measurements go into a logarithmic formula that correlates with body density.
How accurate is a tape-measure body fat calculator?
Usually within about 3–4 percentage points of a DEXA scan — good for a free at-home estimate. Accuracy depends on measuring in the right places with a snug, level tape.
Where do I measure my waist, neck and hips?
Neck just below the larynx, waist at the navel (men) or narrowest point (women), and hips at the widest point. Keep the tape level and snug on bare skin.
What is a healthy body fat percentage?
For men, about 14–24% is fitness-to-average and 6–13% athletic. For women, about 21–31% is fitness-to-average and 14–20% athletic.
What is the difference between body fat and BMI?
BMI uses only height and weight, so muscle can read as "overweight". Body fat percentage estimates how much of your weight is actually fat.
How can I lower my body fat percentage?
A modest calorie deficit, enough protein, strength training and daily activity lower fat while keeping muscle. Aim for gradual change, not crash dieting.