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Estimate your body fat percentage using the U.S. Navy method, which relies on circumference measurements.
Enter your measurements according to the U.S. Navy guidelines.
17.5%
Average
Normal range - but room for improvement
Everything you need to know
Body fat percentage is the proportion of your total body weight that is made up of fat tissue. Unlike BMI, which only uses height and weight, body fat percentage provides a much more accurate picture of your body composition and fitness level. Two people can weigh the same and have the same BMI but look completely different depending on their muscle mass—and body fat percentage reveals that difference.
Understanding your body fat percentage is crucial because it tells you what portion of your weight is functional (muscle, bone, organs) versus stored fat. This is far more important than the number on the scale. The U.S. Navy developed a reliable method for estimating body fat using simple circumference measurements of your waist, neck, and hips (for women). This calculator uses that proven formula to give you an accurate assessment of your body composition and how it compares to healthy ranges for your age and gender.
Our body fat calculator uses the U.S. Navy measurement method:
Select Your Gender
Enter Your Measurements
Enter Your Weight (optional)
Review Your Results
The U.S. Navy developed this formula based on thousands of measurements and is highly accurate for the general population.
For Men:
Body Fat % = 495 / (1.0324 - 0.19077 × log10(waist - neck) + 0.15456 × log10(height)) - 450
For Women:
Body Fat % = 495 / (1.29579 - 0.35004 × log10(waist + hip - neck) + 0.22100 × log10(height)) - 450
Scenario: A 35-year-old male with the following measurements:
Calculation:
Interpretation: At 19.2%, this person is in the "Average" category but close to the "Fitness" range.
| Category | Men | Women | Meaning |
|---|---|---|---|
| Essential Fat | 2-5% | 10-13% | Minimum needed for survival and basic functions |
| Athletes | 6-13% | 14-20% | Very lean, optimized for performance |
| Fitness | 14-17% | 21-24% | Healthy and fit with visible muscle definition |
| Average | 18-24% | 25-31% | Normal for general population |
| Obese | 25%+ | 32%+ | Health risks increase significantly |
Key Insight: A person weighing 185 lbs with 19.2% body fat has approximately 36 lbs of fat mass and 149 lbs of lean body mass—very different from someone at the same weight with 30% body fat.
Body Fat (U.S. Navy Method) calculations support health and fitness goals in many ways:
Suppose you want to lose 20 pounds in a healthy, sustainable manner. By calculating your body fat (u.s. navy method), you can determine a safe daily calorie target, set appropriate exercise goals, and track whether your plan is working as expected.
Scenario: 30-year-old male, height 5'10" (178 cm), weight 190 lbs (86 kg), neck 16.5", waist 36"
U.S. Navy Formula for Men:
Calculation:
Result:
Interpretation: This person is in the "fit" category (10-20% body fat). With continued strength training and moderate calorie intake, they could reach 15% for a lean appearance.
Recalculate whenever your weight changes by more than 5-10 pounds, your activity level shifts significantly, or your goals change. For weight loss or muscle gain programs, monthly recalculation ensures your targets stay appropriate.
Different calculators may use different formulas or population datasets. The Mifflin-St Jeor equation, Harris-Benedict equation, and Katch-McArdle formula all produce slightly different BMR estimates. Consistency matters more than the specific formula used.
Calculators provide estimates based on population averages. Individual metabolism varies due to genetics, hormones, and body composition. Use calculator results as a starting point and adjust based on your body's actual response over 2-4 weeks.
Healthy ranges vary by age and gender: Men typically 10-20%, women 18-28%. Athletes may be 6-15% (men) or 14-20% (women). Very low body fat (<5% men, <12% women) can be unhealthy.
Monthly measurements are sufficient for most people. More frequent measurements add noise without meaningful data. Track trends over 3-4 months rather than week-to-week changes.
DEXA scans and underwater weighing are most accurate. Calipers are practical but require skilled technique. This calculator provides reasonable estimates for tracking progress.
BMI Calculator • TDEE Calculator • Calorie Calculator • Lean Body Mass Calculator
This calculator is provided for educational and informational purposes only. It is not medical, fitness, nutritional, or professional advice. Results are estimates based on the assumptions and inputs you provide.
Actual results may differ significantly due to:
Do not rely on this calculator for:
Before making any health or fitness decisions, consult with:
Past performance and estimates do not guarantee future results. Always verify important information independently and consult qualified professionals for your individual circumstances.