Health & Body Composition
Body Fat Calculator
Estimate your body fat percentage with the U.S. Navy circumference method, only a tape measure needed. See your fat mass, lean mass and category instantly.
Body fat percentage is the share of total body weight made up of fat mass. For adult men, 10–20% is generally considered healthy; for women, 18–28% is typical. It's a more direct measure of body composition than BMI.
Healthy: men 10–20%, women 18–28%.
Method: U.S. Navy circumference formula.
More direct than BMI, tells fat from muscle.
Calculate Your Body Fat
Your Body Fat
What Is Body Fat?
Body fat percentage is the proportion of your total body weight made up of fat mass. The rest, muscle, bone, organs, and water, is lean body mass.
This calculator applies the U.S. Navy circumference method, which estimates body fat from tape measurements and height. It's the same approach used by military body-composition programs, requires no equipment, and is more informative than BMI for muscular builds.
How It Is Calculated
Men: BF% = 495 ÷ (1.0324 − 0.19077·log10(waist − neck) + 0.15456·log10(height)) − 450
Women: BF% = 495 ÷ (1.29579 − 0.35004·log10(waist + hip − neck) + 0.22100·log10(height)) − 450
Example: Example (man): waist 82 cm, neck 38 cm, height 175 cm → about 15.6% body fat
Body fat categories (ACE, by sex)
| 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%+ |
Limitations
- Tape accuracy depends on measuring technique, waist at the navel, neck below the larynx.
- Hydration and time of day affect results; measure under consistent conditions.
- DEXA or hydrostatic weighing are more accurate but need equipment.
- Body fat standards differ by age, so treat category bands as general guidance.
Sources & Review
References used for this calculator’s formulas and thresholds:
Body Fat FAQ
What body fat percentage is healthy?
For men, 10–20% is generally healthy; for women, 18–28%. Athletes sit lower, and healthy ranges rise slightly with age.
How accurate is the Navy body fat method?
The Navy circumference method is accurate to within roughly 3–4 percentage points for most people when measurements are taken carefully, making it a practical home estimate.
How do I measure my waist correctly?
Wrap the tape horizontally around your abdomen at the level of the navel, relaxed, not pulling the tape tight, at the end of a normal exhale.
Why is my BMI high but body fat low?
BMI can't distinguish muscle from fat. Muscular people often have a high BMI but a low body fat percentage, body composition is the better measure for them.
A note before you begin: this tool offers educational estimates only. It cannot replace advice from your doctor or another qualified professional.