This calculator uses the US Navy circumference method to estimate body fat percentage from body measurements. It requires only a tape measure and is reasonably accurate for most people. The method uses waist, neck and (for females) hip circumferences along with height to estimate the ratio of fat to total body mass.

1. Select your sex.
2. Enter your weight and height.
3. Measure your waist at the narrowest point (or at the navel for males).
4. Measure your neck just below the larynx.
5. For females, measure hips at the widest point.
6. Click Calculate.

Male, 80 kg, 178 cm, waist 85 cm, neck 38 cm.
Estimated body fat ≈ 16.4% | Fat mass ≈ 13.1 kg | Lean mass ≈ 66.9 kg

Body fat percentage is a more informative health metric than BMI because it distinguishes fat from muscle. The categories (athletic, fitness, average) are general guidelines. Accurate body fat measurement requires DEXA scanning or hydrostatic weighing — circumference methods are estimates with ±3–5% error.

• Measuring waist at the wrong point — for males, measure at the navel; for females, at the narrowest point.
• Measuring neck too high — measure just below the larynx (Adam's apple).
• Expecting high precision — circumference methods have inherent variability.

How accurate is the US Navy method?

The US Navy method typically has an error of ±3–5% compared to DEXA scanning. It is a reasonable estimate for most people but less accurate for very muscular or very obese individuals.

What is a healthy body fat percentage?

General guidelines: Males — athletic 6–13%, fitness 14–17%, average 18–24%, obese 25%+. Females — athletic 14–20%, fitness 21–24%, average 25–31%, obese 32%+. These are approximate ranges.

Why does this method need hip measurements for females?

Fat distribution differs between sexes. Females typically carry more fat around the hips and thighs, so the hip measurement improves accuracy of the estimate.