Body Fat Calculator
Estimate your body fat percentage using the U.S. Navy method with neck, waist, and hip measurements.
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How This Calculator Works
Uses the U.S. Navy circumference method developed by Hodgdon and Beckett. Validated against DEXA scans with accuracy of ±3-4%.
Body Fat Categories
Essential: Men 2-5%, Women 10-13%. Athletes: Men 6-13%, Women 14-20%. Fitness: Men 14-17%, Women 21-24%. Average: Men 18-24%, Women 25-31%.
Body Fat Percentage Ranges
| 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%+ |
Methods of Measuring Body Fat
The Navy circumference method used here is one of several approaches to estimating body fat. Each has trade-offs between accuracy, cost, and accessibility.
DEXA Scan (Dual-Energy X-ray Absorptiometry): Considered the gold standard. Accuracy: ±1-2%. Cost: $75-150 per scan. Available at medical facilities and some gyms. Provides detailed body composition including bone density and regional fat distribution.
Hydrostatic Weighing: Underwater weighing. Accuracy: ±1.5-2%. Cost: $40-75. Less widely available. Based on the principle that lean tissue is denser than fat tissue.
Bioelectrical Impedance (BIA): Used in body composition scales. Accuracy: ±3-5%. Cost: $30-200 for home devices. Highly variable based on hydration, food intake, and time of day. Best used for tracking trends rather than absolute values.
Navy Circumference Method: Used by this calculator. Accuracy: ±3-4%. Cost: free (just a tape measure). Validated against hydrostatic weighing in the original 1984 study by Hodgdon and Beckett. Best for repeated self-measurement tracking.
Skinfold Calipers: Accuracy: ±3-4% when performed by trained technician. Cost: $10-30 for calipers. Measures subcutaneous fat at specific body sites. Accuracy depends heavily on the skill of the person taking measurements.
Body Fat and Health Outcomes
Research published in the American Journal of Clinical Nutrition found that body fat percentage is a better predictor of cardiometabolic risk than BMI alone. Adults with normal BMI but high body fat ("metabolically obese normal weight") had a 2-3x higher risk of metabolic syndrome compared to those with normal BMI and normal body fat.
For optimal body composition, combine fat percentage tracking with BMI, waist-to-hip ratio (for fat distribution), and lean body mass. Use the Calorie Calculator and Macro Calculator to set nutrition targets that support your body composition goals.
Measurement Methods Compared
DEXA Scan: Gold standard, ±1–2% accuracy, $75–150 per scan. Hydrostatic Weighing: ±1.5–2%, $40–75. BIA Scales: ±3–5%, $30–200 for home devices — variable with hydration. Navy Method (this calculator): ±3–4%, free with tape measure. Skinfold Calipers: ±3–4%, depends on technician skill.
Body Fat and Cardiometabolic Risk
Research in the American Journal of Clinical Nutrition found body fat percentage predicts cardiometabolic risk better than BMI alone. Adults with normal BMI but high body fat — "metabolically obese normal weight" — had 2–3x higher risk of metabolic syndrome. Track progress with lean body mass, waist-to-hip ratio, and body type analysis. Manage composition through your TDEE and macro targets.
Frequently Asked Questions
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