What is body fat percentage?
Body fat percentage is the share of your weight that is fat. It says more about health than weight or BMI alone, because two people with the same weight can have very different amounts of muscle and fat.
This calculator uses the US Navy tape method, which needs only a tape measure, and compares it with a BMI-based estimate.
How it is calculated
Men: 495 ÷ (1.0324 − 0.19077 × log₁₀(waist − neck) + 0.15456 × log₁₀(height)) − 450
Women: 495 ÷ (1.29579 − 0.35004 × log₁₀(waist + hip − neck) + 0.221 × log₁₀(height)) − 450
All measurements are in centimetres. The BMI method uses 1.20 × BMI + 0.23 × age − 10.8 × (1 for men, 0 for women) − 5.4.
Worked example
Man, 178 cm, neck 38 cm, waist 85 cm
- Navy method
- 16.4%
- Category
- Fitness
- BMI method (30 yrs, BMI 24.2)
- 19.8%
Body fat categories
Measure neck below the larynx, waist at the navel and hips at the widest point, relaxed, in the morning.
| 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%+ |
Tape methods are usually within 3–4 percentage points of a DEXA scan. Take the average of two or three measurements for a steadier result.