No. DEXA and clinical methods assess composition more directly; tape is an estimate.
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Estimate body fat percentage from circumferences with explicit limitations.
This calculator estimates body fat percentage from tape-measure circumferences using the U.S. Navy (Hodgdon-Beckett) equations. Men enter height, neck and waist; women add the hip, because the female equation combines waist + hip − neck. The formulas work on logarithms of the differences between those measurements and height, so the tool converts centimetres to inches internally. If you enter your weight, it also splits the result into fat mass (weight × percentage) and lean mass (weight − fat mass). Before calculating, it checks that the measurements are plausible and requires, in the male formula, that the waist be larger than the neck, and in the female formula, that waist plus hip exceed the neck. It is a field method: cheap and accessible, but with meaningful error that depends on tape technique and anatomical landmarks, quite different from DEXA or hydrostatic weighing. It works best for tracking trends with consistent technique, never as a diagnosis; consult a professional.
The U.S. Navy method estimates body density from logarithmic relationships between height and circumferences. For men it uses the difference between waist and neck; for women, the sum of waist and hip minus the neck. The larger that difference is relative to height, the higher the estimated fat.
The original equations were calibrated in inches, so the tool converts your centimetre measurements automatically. When you add weight, the result is also split into fat mass and lean mass, remembering that lean mass includes water, bone, organs and muscle, not only muscle.
Example 1, a man of 1.80 m with a 38 cm neck and 90 cm waist: the estimate lands around 20% fat. At 80 kg of body weight, that is about 16 kg of fat mass and 64 kg of lean mass.
Example 2, a woman of 1.65 m with a 32 cm neck, 74 cm waist and 96 cm hip: the estimate is around 28%. At 65 kg, that is roughly 18 kg of fat mass and 47 kg of lean mass. Small tape variations, one or two centimetres at the waist, already shift these percentages.
NCBI describes anthropometric measurements as noninvasive but subject to instrument, landmark and training error. Waist and hip have more variability than weight and height, so repeating the measurement the same way is what makes the trend reliable.
The estimate does not equal DEXA, hydrostatic weighing or bioimpedance, and it should not guide diagnosis, eating-disorder dieting or a decision about an elite athlete without a professional. Read the trend over time, not a single number.
Paste the code into your HTML and the tool shows up on your page, without J-Kit's navigation and ads. It still runs in the browser of whoever visits your site.
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src="https://jkit.tools/embed/en-US/body-fat-calculator"
width="100%"
height="600"
style="border:0"
loading="lazy"
title="Body Fat Calculator"
></iframe>These references help contextualize formulas, standards, APIs and limitations used on this page. They do not replace professional validation when a result has legal, financial, medical or operational impact.
No. DEXA and clinical methods assess composition more directly; tape is an estimate.
Medical disclaimer: tape-measure estimates can have meaningful error. Do not use for diagnosis, eating disorders, elite athletes or clinical decisions without a professional.
The method uses logarithmic relationships between height, neck, waist and hip. Tape placement errors can noticeably change the result.
Navy-style circumference equations in inches; real body composition requires validated methods and context.
Body measurements stay in your browser and are not sent to analytics.