Body Fat Calculator
Calculate your body fat percentage using the U.S. Navy method
About Body Fat Calculation
This calculator uses the U.S. Navy Method to estimate body fat percentage based on circumference measurements. Developed by the U.S. Navy and widely adopted by the military, this method provides a reasonably accurate estimate without requiring specialized equipment.
How the U.S. Navy Method Works
The method uses mathematical formulas that correlate body circumference measurements with body density and then estimates body fat percentage. The formulas differ for men and women:
- For men: Uses neck and waist circumference along with height
- For women: Uses neck, waist, and hip circumference along with height
Accuracy and Limitations
The U.S. Navy Method has a standard error of 3-4% compared to more precise methods like DEXA scans. It tends to be more accurate for people with average body types and less accurate for:
- Athletes with significant muscle mass (may overestimate body fat)
- People with unusual fat distribution patterns
- Extremely lean individuals or those with obesity
Understanding Your Results
Body fat percentage categories for men:
- Essential Fat: 2-5% (minimum needed for basic physical functions)
- Athletic: 6-13% (typical for competitive athletes)
- Fitness: 14-17% (lean, defined musculature)
- Average: 18-24% (typical healthy range)
- Obese: 25%+ (increased health risk)
Body fat percentage categories for women:
- Essential Fat: 10-13% (minimum needed for basic physical functions)
- Athletic: 14-20% (typical for competitive athletes)
- Fitness: 21-24% (lean, defined musculature)
- Average: 25-31% (typical healthy range)
- Obese: 32%+ (increased health risk)
How to Measure Correctly
- Neck: Measure just below the larynx (Adam's apple) with the tape sloping slightly downward to the front. Keep the tape perpendicular to the long axis of the neck.
- Waist: Measure at the narrowest point, usually just above the belly button. If there is no obvious narrowest point, measure at the level of the belly button. Keep the tape horizontal.
- Hip: (Women only) Measure at the widest point around the buttocks with feet together. The tape should be horizontal around the body.
- Height: Measure without shoes, standing straight with back against a wall.
For the most accurate results, take each measurement 2-3 times and use the average. Measurements should be taken while standing with normal posture, at the end of a normal exhalation.
Other Body Fat Measurement Methods
While the Navy Method is convenient, other methods for measuring body fat include:
- DEXA Scan: Most accurate (±1-2% error), uses X-ray technology
- Hydrostatic Weighing: Very accurate (±1.5-2% error), requires specialized equipment
- Skinfold Calipers: Moderate accuracy (±3-5% error), requires proper technique
- Bioelectrical Impedance: Variable accuracy (±3-8% error), affected by hydration