What is body fat percentage?
Body fat percentage is the proportion of your total body weight that is fat mass. The rest — muscle, bone, water, organs — is lean mass. Unlike BMI, which can't distinguish between fat and muscle, body fat percentage gives you a direct picture of your body composition.
Essential fat is the minimum amount of fat required for basic physiological function — it's stored in organs, bone marrow, and the nervous system. Storage fat is the additional fat stored in adipose tissue, which serves as an energy reserve and provides thermal insulation.
Healthy ranges by sex and age
Body fat norms differ significantly between men and women. Women naturally carry more fat due to hormonal differences, reproductive function, and differences in fat distribution.
| Category | Women | Men |
|---|---|---|
| Essential fat | 10–13% | 2–5% |
| Athletic | 14–20% | 6–13% |
| Fitness | 21–24% | 14–17% |
| Acceptable | 25–31% | 18–24% |
| Obese | 32%+ | 25%+ |
📌 Note on age
Healthy body fat ranges shift upward with age. A 55-year-old woman at 28% body fat is in a different situation than a 25-year-old at the same percentage. Age-adjusted charts provide more context.
How to measure body fat percentage
DEXA scan
The gold standard. A DEXA scan uses low-dose X-ray to measure bone density, lean mass, and fat mass with high accuracy (±1–2%). It also shows regional fat distribution — including visceral fat around organs, which is the metabolically dangerous type. Cost is typically $50–150.
Hydrostatic weighing
Highly accurate (±2–3%) and involves being submerged in water. Less commonly available than DEXA but used in research and sports science facilities.
Skinfold calipers
A trained practitioner measures skinfold thickness at multiple body sites. Accuracy depends heavily on skill — results can vary by ±3–4% between testers. Inexpensive and widely available.
Bioelectrical impedance (BIA)
Used in most consumer body composition scales and handheld devices. A low-level electrical current passes through the body; fat and lean tissue conduct it differently. Accuracy is moderate (±3–5%) and highly affected by hydration status. Take readings under consistent conditions — same time of day, same hydration level.
Navy method (circumference)
Uses measurements of neck, waist, and hips to estimate body fat. Accuracy is reasonable (±3–4%) and requires no equipment beyond a measuring tape. This is the method used in our Body Fat % Estimator.
Why visceral fat matters most
Not all fat is equal. Subcutaneous fat sits just below the skin and is relatively benign. Visceral fat wraps around the internal organs in the abdominal cavity and is strongly associated with insulin resistance, type 2 diabetes, cardiovascular disease, and inflammation.
People with the "apple" body shape — fat concentrated around the abdomen — tend to carry more visceral fat and face higher metabolic risk than people with the "pear" shape, even at the same total body fat percentage. Waist circumference is a simple proxy: over 88cm (35in) for women or 102cm (40in) for men suggests elevated risk.
Estimate your body fat percentage using the US Navy method — no equipment needed.
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