Use this free body fat calculator to estimate your body fat percentage using the US Navy method. Enter your measurements to get an instant body fat estimate and see which fitness category you fall into for your age and sex.
Body Fat Calculator (Navy Method)
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Body composition estimate
Total weight
Fat mass
Lean mass
How to use this Body Fat calculator
1. Select your sex using the Male or Female tab — the US Navy formula uses different measurements for each.
2. Measure your height in inches while standing straight without shoes.
3. Measure your neck circumference just below the larynx (Adam's apple), sloping slightly downward at the front. Keep the tape snug but not compressing the skin.
4. Measure your waist circumference at the navel for men, or at the narrowest point for women.
5. Women only: measure your hip circumference at the widest point of the hips and buttocks.
6. Enter your weight and click Calculate Body Fat to see your estimated body fat percentage, fitness category, fat mass, and lean mass.
Frequently asked questions
Q: What is a healthy body fat percentage?
A: Healthy body fat ranges differ by sex. For men, 6% to 17% is considered athletic to fit, with 18% to 24% being average. For women, 14% to 24% is athletic to fit, with 25% to 31% being average. Body fat above 25% for men and 32% for women is generally classified as obese. Essential fat — the minimum needed for basic physiological function — is around 3% to 5% for men and 10% to 13% for women.
Q: How accurate is the Navy body fat method?
A: The US Navy circumference method has a margin of error of approximately 3% to 4% compared to more precise methods like DEXA scanning or hydrostatic weighing. It is accurate enough for tracking progress over time and for general fitness assessment, but should not be used for medical diagnosis. Consistency in measurement technique is more important than absolute accuracy when tracking changes.
Q: Where exactly do I measure my waist?
A: For men, measure the waist at the level of the navel (belly button). For women, measure at the narrowest point of the torso, which is typically just above the navel. Take the measurement after exhaling normally — do not suck in your stomach or hold your breath. Measure at the same time of day each time you track progress.
Q: Why is the female formula different from the male formula?
A: Women naturally carry more essential body fat than men due to hormonal and reproductive physiology. The US Navy formula accounts for this by using a different set of measurements and coefficients for each sex. Women require the hip measurement because fat distribution patterns differ — women tend to carry more fat in the hip and thigh region, which the formula factors in.
Q: How often should I measure my body fat?
A: Body fat changes slowly, so measuring more than once every two to four weeks is unlikely to show meaningful changes and can be discouraging. Consistency in measurement conditions matters more than frequency — measure at the same time of day, with the same tools, under the same conditions each time for the most reliable tracking.