How the Navy method works
This is the Navy circumference method (a tape estimate). It is not an official Navy or DoD pass/fail. Men: height, neck, and waist. Women: height, neck, waist, and hips. Measure on skin, tape snug, not crushing.
Women: 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387
Need BMI instead? Use the free BMI calculator. Different tool, different number.
ACE categories
We label the estimate with common ACE adult ranges (essential, athletes, fitness, average, obese). Categories are screening language, not a diagnosis. Fat mass vs lean mass is just weight × that percent.
Why tape differs from DEXA/scales
DEXA, BodPod, and smart scales use different assumptions. Tape misses where fat sits and how much is muscle. If waist ≤ neck the formula breaks — remeasure. Treat this as a trend helper, not a lab result.
Not medical advice
This tool is for education and planning. It does not diagnose, treat, or replace care from a qualified professional.
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