Body Fat Calculator
Estimate your body fat percentage from a few tape measurements using the US Navy circumference method.
The US Navy method
The US Navy developed this method to estimate body fat without special equipment. It uses height and neck, waist and (for women) hip measurements. Studies comparing it with lab methods such as DEXA scans typically find it within about 3–4 percentage points for most people.
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
All measurements are in centimeters; the calculator converts inches automatically.
How to measure
- Use a flexible tape, snug but not compressing the skin, and measure on bare skin.
- Neck: just below the Adam's apple, with the tape sloping slightly down at the front.
- Waist: men at the navel, women at the narrowest point; breathe out normally first.
- Hips (women): around the widest part of the buttocks.
- Take each measurement twice and use the average. Measure at the same time of day to track changes.
Body fat categories
| 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%+ | 25%+ |
Source: American Council on Exercise. Healthy ranges rise slightly with age.
Frequently asked questions
How accurate is the Navy body fat method?
For most people it is within about 3–4 percentage points of laboratory methods. It is less accurate for very lean or very muscular people and for those with unusual fat distribution.
What is a healthy body fat percentage?
For adults, roughly 21–31% for women and 14–24% for men is considered healthy, with athletes typically lower.
How can I measure body fat more accurately?
DEXA scans, hydrostatic weighing and air displacement (Bod Pod) are the most accurate options. Smart scales are convenient but can vary with hydration.
Last reviewed Oct 20, 2026. Results are estimates; check important decisions with a qualified professional.