Body Fat Calculator
Estimate your body fat percentage with just a tape measure — no equipment needed.
Measurements guide: Waist — measure at the narrowest point (or navel). Neck — measure below the larynx. Hip (women only) — measure at the widest point.
How this calculator works
This tool uses the US Navy circumference method, which estimates body fat from neck, waist, and (for women) hip measurements alongside height. The formula uses logarithmic relationships between these measurements to predict the proportion of fat mass relative to total body weight.
What the result means
The result splits your weight into fat mass and lean mass. Lean mass includes muscle, bone, organs, and water — not just muscle alone. Tracking body fat percentage over time is more informative than tracking weight alone, since it reflects actual body composition changes rather than fluctuations in water or glycogen.
Frequently Asked Questions
- What is the US Navy body fat method?
- The US Navy method estimates body fat percentage using circumference measurements (neck, waist, and hip for women) and height. It was developed for military fitness assessments and correlates well with DEXA scan results for most body types.
- How accurate is this method?
- Studies show accuracy within ±3–4% for most individuals compared to DEXA scans. It is less accurate for very lean (sub-10% for men) or very high body fat individuals. DEXA remains the gold standard.
- Where exactly do I measure my waist?
- For men, measure at the navel. For women, measure at the narrowest point of the torso (usually just above the navel). Measure after a normal exhale — do not suck in.
- What is a healthy body fat percentage?
- For men: 10–20% is considered fit to acceptable. For women: 20–30%. Athletes typically sit at 6–13% (men) or 14–20% (women). Essential fat is approximately 3–5% for men and 10–13% for women.