Calculate your body fat percentage using Navy method or BMI method with step-by-step solutions
Male, Navy method
The Navy method uses body measurements to estimate body fat percentage. It's considered more accurate than BMI-based methods.
For Men: Requires weight, height, waist, and neck measurements
For Women: Requires weight, height, waist, neck, and hip measurements
Men: Essential (2-5%), Athletes (6-13%), Fitness (14-17%), Average (18-24%), Obese (25%+)
Women: Essential (10-13%), Athletes (14-20%), Fitness (21-24%), Average (25-31%), Obese (32%+)
Most people use body fat percentage for one of three goals: improving metabolic health, optimizing sports performance, or planning a sustainable fat-loss phase while preserving lean mass. The Navy method estimates body density from circumferences, then converts that estimate to body fat percentage. The BMI-based shortcut is useful when circumference measurements are not available, but it is less precise for muscular individuals, older adults, and people with unusual fat distribution.
Example: a male at 180 lb with 34 in waist, 15 in neck, and 70 in height might land near the high-teens body fat range. If he reduces waist circumference by 2 inches while keeping weight stable through resistance training, estimated body fat usually drops meaningfully even if the scale barely changes. That is why body-composition metrics often track progress better than body weight alone.
Common mistakes: measuring at different times of day, pulling the tape too tight, and comparing results from different methods as if they were identical. Hydration, sodium intake, menstrual cycle phase, and post-workout inflammation can all shift circumference readings. For trend tracking, measure under similar conditions each week and use a rolling 4-week average.
In practice, body fat percentage works best alongside waist-to-height ratio, resting heart rate, sleep quality, and strength performance. If body fat drops but strength and energy collapse, your calorie deficit may be too aggressive. If body fat stays flat but strength rises and waist slowly decreases, you may be recomping effectively. Context matters more than chasing a single "perfect" percentage.
A useful planning formula is:
If you weigh 160 lb at 30% body fat, fat mass is 48 lb and lean mass is 112 lb. If you cut to 25% while preserving lean mass, projected body weight becomes 149 lb. This kind of estimate helps set realistic timeline targets for nutrition and training.
Medical context is important: extremely low body fat can impair hormones, immune function, and recovery, while very high body fat is associated with higher cardiometabolic risk. Use this calculator as a screening and coaching tool, not as a diagnosis. Pair your results with clinical measurements such as blood pressure, lipid panel, and glucose markers when making health decisions.
Calculate body fat to place your marker on the range scale.
Health disclaimer: this body fat calculator is for educational fitness planning and is not a substitute for medical advice, diagnosis, or treatment. If you have chronic conditions, eating disorder history, pregnancy considerations, or rapid weight changes, review results with a licensed healthcare professional.