Body Fat Calculator
Estimate your body fat percentage using the US Navy circumference method. Enter your height, weight, and body measurements to find your fat mass, lean body mass, and fitness category.
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Understanding Body Fat Percentage
How the Navy Method Works
The US Navy circumference method estimates body fat using height and body circumference measurements rather than scale weight alone. For men, it uses neck and waist; for women, it adds hip circumference. The formula applies a logarithmic model developed from large military populations, making it practical and reasonably accurate without expensive equipment.
Healthy Body Fat Ranges
Body fat guidelines vary by sex due to hormonal and reproductive differences. Women naturally carry more essential fat. For men, the fitness range is 14–17%; for women, 21–24%. Athletic individuals often fall in the 6–13% (men) or 14–20% (women) range. Extremely low body fat below the essential threshold is dangerous and associated with hormonal disruption and organ damage.
Body Recomposition
Body recomposition — simultaneously reducing fat and building muscle — is achievable especially for beginners and those returning from a break. It requires eating near maintenance calories with high protein intake (0.7–1 g per lb of bodyweight), combined with progressive resistance training. Progress is measured in body fat percentage and lean mass changes rather than scale weight alone.
Body Fat % vs BMI
BMI (Body Mass Index) uses only height and weight and cannot distinguish muscle from fat. A muscular athlete can have an "overweight" BMI despite low body fat. Body fat percentage is a more direct and health-relevant metric. The Navy method provides a practical middle ground — more informative than BMI, more accessible than lab-based methods like DEXA scanning or hydrostatic weighing.
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Open calculator →FAQ
What is a healthy body fat percentage?
Healthy body fat ranges differ by sex. For men, 6–17% is generally considered athletic to fitness level, and 18–24% is average. For women, 14–24% is athletic to fitness level, and 25–31% is average. Essential fat — the minimum needed for basic physiological function — is around 2–5% for men and 10–13% for women. Above 25% (men) or 32% (women) is classified as obese by most guidelines.
How accurate is the US Navy body fat method?
The US Navy circumference method has a margin of error of roughly 3–4 percentage points compared to DEXA scanning — the gold standard. It is more accurate than BMI-based estimates because it accounts for body shape and circumference distribution. For best results, measure in the morning before eating, keep the tape parallel to the floor, and take each measurement twice to confirm consistency.
How can I reduce my body fat percentage?
Reducing body fat requires a sustained calorie deficit combined with adequate protein intake (0.7–1 g per lb of bodyweight) to preserve muscle mass. Resistance training helps maintain or build lean mass during a cut, improving body composition even when scale weight changes slowly. Aim for a moderate deficit of 300–500 calories per day rather than drastic restriction, which risks muscle loss and metabolic adaptation.
What does essential body fat mean?
Essential fat is the minimum amount of fat required for normal physiological function, including hormone regulation, nerve insulation, organ protection, and vitamin absorption. For men this is approximately 2–5% and for women 10–13%. Falling below essential fat levels is dangerous and associated with hormonal dysfunction, bone density loss, and organ damage. Athletes should not pursue body fat levels below the essential range.
What is the difference between body fat percentage and BMI?
BMI uses only height and weight, making no distinction between muscle and fat. A muscular athlete may have a high BMI but low body fat. Body fat percentage directly measures the proportion of fat tissue in your body, making it a more meaningful health indicator. The Navy method estimates body fat using body circumferences, which better reflects fat distribution than weight alone, though it is still an estimate compared to DEXA or hydrostatic weighing.