How to use the Body Fat Calculator
- Measure your neck and waist (and hips if you're female) with a soft tape.
- Enter your height and measurements.
- Optionally enter your weight to see fat mass and lean mass.
What does this tool do?
The U.S. Navy method estimates body fat from circumference measurements and height. It was developed for military fitness screening and is reasonably accurate for most people, without special equipment.
For men it uses the neck and waist; for women it also uses the hips, because fat distribution differs between sexes.
Why use it?
- No calipers or scales needed.
- Tracks progress better than weight alone.
- Shows fat and lean mass.
Body fat categories (American Council on Exercise)
Typical ranges:
| Category | Women | Men |
|---|---|---|
| Essential fat | 10–13% | 2–5% |
| Athletes | 14–20% | 6–13% |
| Fitness | 21–24% | 14–17% |
| Average | 25–31% | 18–24% |
| Above average | 32%+ | 25%+ |
The formula
Men: 495 ÷ (1.0324 − 0.19077 × log₁₀(waist − neck) + 0.15456 × log₁₀(height)) − 450
Women: 495 ÷ (1.29579 − 0.35004 × log₁₀(waist + hip − neck) + 0.22100 × log₁₀(height)) − 450
All measurements in centimeters.
Accuracy and limits
- This is a general estimate for healthy adults, not medical advice. Talk to a doctor or registered dietitian about your own situation.
- Typically within 3–4 percentage points of laboratory methods (such as DEXA). Measure the same way each time to track changes reliably.
Privacy
The calculation happens instantly in your browser. The numbers you enter are not sent to our servers or saved. There's no account to create and nothing to install.
Last reviewed by the M2Toolkit team.