Body Fat Calculator
Estimate your body fat percentage with the US Navy tape method or the BMI-based formula. See your fitness category, fat mass vs lean mass split, and how you compare on the ACE body-fat scale for men and women.
Body fat
17.2 %
Fat mass
13.4 kg
Lean mass
64.6 kg
Where you fall (male)
Body composition
How the US Navy method works
The US Navy circumference method estimates body fat from a few tape measurements instead of calipers or lab equipment. It works because fat distributes predictably around the neck, waist, and hips relative to height.
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
Measure in a relaxed state: neck below the larynx, waist at the navel for men and the narrowest point for women, hips at the widest point. The BMI method (Deurenberg equation) needs no tape — it derives fat from BMI, age, and sex, but is less accurate for muscular or older bodies.
Body-fat categories (ACE)
| 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%+ |
Women carry more essential fat than men for hormonal and reproductive function, which is why every band sits higher.
How accurate is each method?
Bars show typical agreement with a DEXA reference. Field methods are best used to track change over time, not as an exact single number.
Essential vs storage fat
Essential fat lines organs, nerves, and bone marrow — drop below it and health fails. Everything above is storage fat, the energy reserve you can change through diet and training.
Lean body mass is everything that is not fat: muscle, bone, water, organs. Tracking lean mass alongside body fat tells you whether weight loss is coming from fat (good) or muscle (avoid).
This tool provides estimates for general fitness tracking and is not medical advice. Consult a professional for clinical assessment.