Body Fat Calculator: Find Your Body Fat Percentage
Estimate your body fat percentage with a simple tape measure using the US Navy method, and see your fat mass, lean mass and where you stand.
How the US Navy body fat formula works
The US Navy developed this method to estimate body fat quickly without special equipment. It uses the fact that fat collects around the waist (and hips in women), while the neck stays relatively lean. Comparing those measurements with your height gives a surprisingly good estimate.
It is far more useful than BMI for active people, because it looks at where your weight is, not just how much you weigh.
The formulas (cm)
How to measure for an accurate result
Measure just below the larynx (Adam’s apple), with the tape sloping slightly down to the front. Don’t flare your neck.
Men: at the belly button. Women: at the narrowest point, usually just above the belly button. Relax and breathe out normally.
Around the widest part of the buttocks, with feet together and the tape level all the way round.
- Measure first thing in the morning, before eating or training.
- Keep the tape snug against bare skin but not pressing in.
- Take each measurement two or three times and use the average.
- Re-measure every 2 to 4 weeks under the same conditions to track change.
Body fat percentage chart
These categories from the American Council on Exercise are the most widely used. Women naturally carry more essential fat than men.
| Category | Women | Men |
|---|---|---|
| Essential fat | 10–13% | 2–5% |
| Athletes | 14–20% | 6–13% |
| Fitness | 21–24% | 14–17% |
| Average | 25–31% | 18–24% |
| Obese | 32% and above | 25% and above |
Body fat measurement methods compared
| Method | Typical accuracy | Cost and access |
|---|---|---|
| DEXA scan | Very good (±1–2%) | Clinic, paid |
| Hydrostatic weighing | Very good | Lab, hard to find |
| US Navy tape method | Good (±3–4%) | Free, at home |
| Skinfold calipers | Good with a skilled tester | Cheap, needs practice |
| Smart scales (BIA) | Variable, affected by hydration | Cheap, at home |
| BMI-based formulas | Rough | Free |
The most useful thing is not the exact number but the trend. Use the same method under the same conditions each time.
What to do with your body fat percentage
Enter your body fat % in our BMR calculator to unlock the Katch-McArdle formula.
Your lean mass helps set protein targets. See our lean body mass calculator.
If you want to lean out, set a safe target with our calorie deficit calculator.
Body fat calculator FAQs
How accurate is the Navy body fat calculator?
For most people it is within about 3 to 4 percentage points of a DEXA scan. It is less accurate for very lean, very muscular or very heavy people, but it is reliable for tracking changes over time.
What is a healthy body fat percentage?
Roughly 14–24% for men and 21–31% for women covers the fitness and average ranges. Very low levels are not healthier and can cause problems.
Is body fat percentage better than BMI?
Yes, for most purposes. BMI only compares weight with height, so muscular people can be labelled overweight. Body fat percentage shows how much of your weight is actually fat.
How fast can I lower my body fat?
Losing about 0.5–1% of body weight per week usually lowers body fat by around 1 percentage point per month, depending on your starting point and how much muscle you keep.
Why do women have higher body fat than men?
Women need more essential fat for hormones and reproduction, so healthy ranges are around 8 to 10 points higher than for men.