worldofcalcsBody Fat Percentage Calculator
Body Fat Percentage Calculator
17.8%
What is body fat percentage?
Body fat percentage is the share of your weight that is fat. It says more about health and fitness than weight or BMI alone, because it separates fat from muscle, bone and water. Two people with the same BMI can have very different body fat, and fat stored around the waist carries the most health risk.
US Navy method
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 are in centimetres. Measure the waist at the navel (men) or the narrowest point (women), the neck just below the voice box, and the hips at the widest point. The method is usually within 3–4 percentage points of a lab scan.
Measuring and reading it
- Measure in the morning, before eating, with a flexible tape held snug but not tight; take each measurement twice.
- Women naturally carry more essential fat than men, so their healthy ranges are about 8 points higher.
- Track the trend rather than one reading: a falling number with stable weight means you are losing fat and gaining muscle.
- Bathroom scales that measure body fat (bioimpedance) vary a lot with hydration; tape methods are often as reliable.
- These are estimates for healthy adults. Speak to a doctor or dietitian if you are pregnant, have a medical condition or plan a big change in diet.
Worked example
- A man 170 cm tall with a 38 cm neck and an 85 cm waist
- Body fat = 495 ÷ (1.0324 − 0.19077 × log₁₀(47) + 0.15456 × log₁₀(170)) − 450 = 17.8%
- That is in the 'average' range for men (18–24% is average; 14–17% is fit)
- The same man with a 95 cm waist measures 25.0%, in the obese range
- A woman 160 cm tall with a 33 cm neck, 75 cm waist and 95 cm hips measures 28.3%
Body fat ranges
Categories commonly used by the American Council on Exercise.
| Category | Men | Women |
|---|---|---|
| Essential fat | 2–5% | 10–13% |
| Athletes | 6–13% | 14–20% |
| Fit | 14–17% | 21–24% |
| Average | 18–24% | 25–31% |
| Obese | 25% and above | 32% and above |
Healthy ranges rise a little with age.