Body Fat Calculator
Estimate your body fat percentage with the US Navy method.
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Your body-fat percentage is the share of your total weight that is fat rather than muscle, bone, organs and water. It tells you far more about your shape and health than the scale alone, because two people at the same weight can carry very different amounts of fat. This calculator estimates your body-fat percentage from a few tape measurements using the US Navy circumference method, then places you in a fitness category so you can see where you stand and track changes over time.
How the US Navy method works
The US Navy circumference method, developed by Hodgdon and Beckett at the Naval Health Research Center in 1984, estimates body fat from the girth of body parts where fat collects, scaled against your height. Men enter their neck, waist and height. Women add a hip measurement, because the female body stores more fat around the hips and a third site makes the estimate more accurate. The formula uses the base-10 logarithm of these circumferences, so the result responds to the difference between your waist and neck rather than raw size.
For a man who is 178 cm tall with a 39 cm neck and an 85 cm waist, the formula returns about 15.7% body fat, which sits in the fitness range. The big advantage over skinfold calipers or bioimpedance scales is that you need nothing but a flexible tape measure, and the readings are repeatable as long as you measure the same way each time.
How to measure accurately
Use a soft tape, keep it level with the floor, and pull it snug without compressing the skin. Measure the neck just below the larynx, sloping slightly down to the front. Men measure the waist horizontally at the navel; women measure at the narrowest point of the torso. For the hip measurement, women circle the widest part of the buttocks. Take each reading first thing in the morning before eating, and measure twice, averaging the two if they differ.
Small errors matter here. A single centimetre on the waist can shift the result by roughly a percentage point, so consistency between sessions is what makes the number useful for tracking.
What is a healthy body-fat percentage
Healthy, fit ranges sit around 10 to 20% for men and 18 to 28% for women. Below that lies the athlete and essential-fat range; above it the average and high-fat categories. Women naturally carry more essential fat than men for hormonal and reproductive function, which is why the categories differ by sex. Treat the figure as an estimate that is usually within about 3 to 4% of a DEXA scan. Its real value is in the trend: measure every few weeks under the same conditions and watch the direction, not a single reading.
How to use
- 01
Measure with a tape
Record your neck and waist (and hips for women) along with your height.
- 02
Enter the numbers
Type your measurements in metric or imperial.
- 03
Read your body fat
See your estimated body-fat percentage and category on the scale.
Frequently Asked Questions
The US Navy formula is within about 3–4% of a DEXA scan for most people — accurate enough to track progress over time.
Men measure at the navel; women at the narrowest point. Keep the tape level and do not pull it tight.
Roughly 10–20% for men and 18–28% for women is considered a healthy, fit range.
Women store more fat around the hips, so the female formula adds hip circumference for an accurate estimate.
Reference data
| Category | Men | Women |
|---|---|---|
| Essential Fat | 2–6% | 10–14% |
| Athlete | 6–14% | 14–21% |
| Fitness | 14–18% | 21–25% |
| Average | 18–25% | 25–32% |
| Obese | ≥ 25% | ≥ 32% |
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Last reviewed June 2026 · Methodology & sources