Body Fat Calculator
Calculate your body fat percentage using the US Navy method. Supports metric and imperial units.
Frequently Asked Questions
What is a healthy body fat percentage?
For men: 6–13% is athlete range, 14–17% is fitness, 18–24% is acceptable. For women: 14–20% is athlete range, 21–24% is fitness, 25–31% is acceptable. Essential fat needed for life functions is 3–5% for men and 10–13% for women. The American Council on Exercise defines 25%+ for men and 32%+ for women as obese.
How accurate is the Navy body fat method?
The US Navy formula estimates body fat within 3–4% of DEXA scan results for most people. It's less accurate for very muscular individuals (overestimates fat) and those with unusual fat distribution. DEXA (dual-energy X-ray) is the gold standard. Calipers are also reasonably accurate when used consistently by the same person.
Can you lose body fat without losing weight?
Yes — body recomposition replaces fat with muscle. If you gain 2 kg of muscle and lose 2 kg of fat, scale weight stays the same but body fat% drops significantly. This is most common in people new to resistance training or returning after a break. It's slower than a focused cut or bulk, but achievable.
What is lean mass?
Lean mass is everything in your body except fat: muscles, bones, organs, water, and connective tissue. A 80 kg person at 20% body fat has 16 kg of fat and 64 kg of lean mass. Preserving or increasing lean mass while reducing fat is the goal of most physique transformations.
How do I measure waist and neck for this calculator?
For waist: measure at the level of your navel (belly button), relaxed and not sucked in. For neck: measure just below the larynx (Adam's apple) at the narrowest point. For hips (women only): measure at the widest point around the buttocks. Use a soft measuring tape and take 2–3 measurements for accuracy.