Body Fat Calculator
Enter your measurements in centimetres to estimate body fat.
The US Navy method estimates body fat from a few circumference measurements and height. It is practical for home use and does not require special equipment beyond a tape measure. Provide measurements in centimetres. The tool applies the published formulas with base 10 logarithms and returns both the percentage and a descriptive fitness band. All processing is local.
How to use
- Select male or female (women require the hip measurement).
- Enter height, neck circumference, and waist circumference in centimetres.
- For women also enter hip circumference at the widest point.
- Read the estimated body fat percent and the category band.
Examples
- Male, 178 cm height, 38 cm neck, 85 cm waist yields about 16 percent, in the fitness range.
- Female, 165 cm, neck 32, waist 78, hip 98 produces about 30 percent, in the average band.
FAQs
- What formula does this use?
- It implements the US Navy (Hodgdon) equations. Men: 495 divided by (1.0324 minus 0.19077 times log10 of (waist minus neck) plus 0.15456 times log10 of height) minus 450. Women use a similar expression with waist plus hip minus neck and slightly different coefficients.
- Why must waist minus neck (or waist plus hip minus neck) be positive?
- The logarithm argument must be positive. A negative or zero value would mean the waist measurement is smaller than the neck (or neck plus hips for women), which is not physically plausible for the formula and produces an invalid result.
- How do the category bands work?
- The bands follow commonly referenced American Council on Exercise ranges and differ by sex. Essential fat is the lowest healthy band, followed by athletes, fitness, average, and above average.
- Is this as accurate as a DEXA or Bod Pod scan?
- No. Circumference methods are convenient estimates with typical errors of a few percentage points. They are useful for tracking trends over time but are not medical grade.
- Are the numbers I enter sent anywhere?
- No. The estimation is performed entirely in your browser. Your measurements are never transmitted.
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