Estimate your body fat percentage using circumference measurements. Visualize body composition, BMI, and personalized health rating based on gender and age. Ideal for fitness tracking, weight management, and health awareness.
Body fat percentage is a key indicator of health beyond BMI. The US Navy / Hodgdon-Beckett method estimates body density using circumference measurements—neck, waist, and hips (for women)—with height. This method is validated against hydrostatic weighing and is widely used by fitness professionals, military, and researchers. Unlike simple BMI, it accounts for fat distribution, offering a more accurate view of body composition.
? US Navy Method Formula (in inches):
For Men: %Fat = 86.010 × log₁₀(Waist − Neck) − 70.041 × log₁₀(Height) + 36.76
For Women: %Fat = 163.205 × log₁₀(Waist + Hip − Neck) − 97.684 × log₁₀(Height) − 78.387
*All measurements converted from cm to inches. Results are age-independent for the core formula; rating uses gender & age guidelines from ACSM/ACE.
Excess body fat, especially visceral fat, increases risk for cardiovascular disease, type 2 diabetes, and metabolic syndrome. Conversely, very low body fat (below essential levels) can disrupt hormonal function. Maintaining a healthy body fat percentage supports energy levels, immunity, and longevity. Our calculator integrates the latest American Council on Exercise (ACE) and NIH classification tables adjusted for age and gender to give you personalized feedback.
| Category | Men (% Fat) | Women (% Fat) | Health Implication |
|---|---|---|---|
| Essential Fat | 2–5% | 10–13% | Minimum for physiological function |
| Athletes | 6–13% | 14–20% | High performance, defined musculature |
| Fitness / Good | 14–17% | 21–24% | Healthy, active lifestyle |
| Acceptable / Average | 18–24% | 25–31% | Standard range for general population |
| Overweight / Obese | >25% | >32% | Increased health risk, consider lifestyle changes |
Note: For older adults (60+), a slightly higher percentage may be acceptable due to natural changes; our age-aware rating adjusts the thresholds to give balanced advice.
Sarah, 38, used the US Navy method monthly while training for a marathon. Over 4 months, her body fat dropped from 28% to 23%, while weight remained stable—demonstrating muscle gain and fat loss. Her BMI stayed “overweight” (26.1), but body fat moved into the fitness category, highlighting the importance of body composition tracking over BMI alone. Our calculator helps you capture such nuanced progress.
The US Navy method correlates highly with DEXA scans (r ≈ 0.85–0.90) in validation studies. However, it may overestimate or underestimate body fat for extreme body types (very muscular individuals or elderly with sarcopenia). It is intended as a reliable, affordable alternative to laboratory methods. For clinical decisions, consult a healthcare provider. This tool follows the original 1984 Hodgdon-Beckett equations, with inch/cm conversions standardized by the National Institute of Health.