Body Fat Calculator
The Body Fat Calculator uses the U.S. Navy circumference method to estimate your body fat percentage from simple tape-measure measurements, no special equipment required. The tool also classifies your result into a category — essential fat, athletic, fit, average, or above average — using different thresholds for men and women to reflect typical differences in fat distribution. Because the formula is sensitive to technique, measuring at the same time of day with the tape snug but not compressing the skin makes repeat measurements more comparable over time.
Switch between U.S. Customary and Metric units.
How This Tool Works
Enter your sex, height, neck, waist, and (for women) hip measurements to calculate your estimated body fat percentage using the U.S. Navy method.
Formula & Method
Men: 495 ÷ (1.0324 − 0.19077×log10(waist−neck) + 0.15456×log10(height)) − 450. Women: 495 ÷ (1.29579 − 0.35004×log10(waist+hip−neck) + 0.22100×log10(height)) − 450 (all measurements in cm).
Example Calculation
A man 70 inches (178 cm) tall with a 15 in (38 cm) neck and 34 in (86 cm) waist has an estimated body fat of about 17.4% — in the "fit" category. For a woman 5'4" tall with a 12 in neck, 28 in waist, and 38 in hip, the estimate comes out to about 27.7%, in the "average" category — the women's formula factors in hip circumference since fat tends to distribute more around the hips and thighs.
Frequently Asked Questions
How accurate is the Navy method?+
It's typically accurate within about 3–4% of more precise methods like DEXA scanning, making it a solid at-home estimate.
Where do I measure my waist?+
Measure around your waist at the level of your navel, keeping the tape snug but not compressing the skin.
Why do women need a hip measurement but men don't?+
The Navy method formula for women includes hip circumference because body fat distribution patterns differ by sex, improving the estimate's accuracy.
Why does my waist need to be larger than my neck measurement?+
The formula subtracts your neck circumference from your waist (plus hip, for women) inside a logarithm, so if waist isn't larger than neck the calculation becomes mathematically invalid. The calculator will show an error asking you to double-check your measurements.
What happens if my measurements produce an unrealistic result?+
The calculator rejects any result below about 2% or above about 75% body fat as physiologically implausible and will prompt you to re-check your inputs — this almost always means a measurement was taken incorrectly rather than a true reading.
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<a href="https://everyfix.net/tools/body-fat-calculator/">Body Fat Calculator</a> by <a href="https://everyfix.net">EveryFix</a>Related Tools
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