Body Fat Calculator
Free online body fat calculator. No sign-up, no installation. Runs entirely in your browser.
Calculate Your Body Composition
What is Body Fat Percentage?
Body fat percentage is the proportion of your body weight that comes from fat tissue. Unlike BMI, which only considers height and weight, body fat percentage provides a more accurate picture of your body composition by distinguishing between fat mass and lean muscle mass. A healthy body fat percentage varies by age and gender, but generally ranges from 10-20% for men and 18-25% for women.
How to Use This Calculator
Select your preferred measurement method based on the data you have available. The Navy Method uses neck, waist, and height measurements (plus hip measurement for women), while the Jackson-Pollock method uses skinfold measurements from three body sites. Enter your personal information including age and gender, choose your preferred units, and the calculator will estimate your body fat percentage and body composition breakdown.
Measurement Methods Explained
Navy Method: Uses circumference measurements of your neck, waist, height, and hips (women only). It's considered one of the most accurate non-invasive methods. You only need a flexible measuring tape.
BMI-Based Estimate: Calculates body fat approximation from your height and weight, adjusted for age and gender. It's the least accurate method but requires minimal data.
Jackson-Pollock Method: Uses skinfold measurements from three specific body sites using calipers. When performed correctly, it provides reliable results comparable to more expensive testing methods.
Frequently Asked Questions
What's a healthy body fat percentage?
Healthy ranges vary by gender and age. For men: Essential (2-5%), Athlete (6-13%), Fitness (14-17%), Average (18-25%). For women: Essential (10-13%), Athlete (14-20%), Fitness (21-24%), Average (25-31%). Anything above 25% for men and 31% for women is considered elevated.
Which method is most accurate?
The Navy Method is generally most accurate for non-invasive measurements (±3-4% error margin). Jackson-Pollock is equally reliable when measurements are taken correctly. BMI-based estimates are less precise but still provide reasonable approximations. For clinical accuracy, hydrostatic weighing or DEXA scans are gold standards.
How do I measure my neck and waist correctly?
Neck: Measure at the narrowest point just below the larynx, keeping tape snug but not tight. Waist: Measure at the level of your navel while standing relaxed with abdomen natural (not sucked in). Use a flexible measuring tape held perpendicular to your body. Measure multiple times for consistency.
How often should I measure my body fat?
Measure monthly for tracking progress. More frequent measurements (weekly or bi-weekly) can be misleading due to natural body water fluctuations. Always measure at the same time of day, in the same conditions, and using the same method for accurate comparisons.
Can I build muscle and lose fat at the same time?
Yes, especially if you're new to exercise or returning after a break. A proper strength training program combined with adequate protein and a slight caloric deficit allows simultaneous fat loss and muscle gain—body recomposition. Track body fat percentage rather than scale weight for the best picture.
Why do my results vary between methods?
Different methods use different formulas and measurement points, so small variations are normal. Navy and Jackson-Pollock may differ by 2-3%. Inconsistent measurement technique also causes variation. Always use the same method and technique when tracking changes over time.