Body Fat Calculator (US Navy)
Tape-test estimates from neck, waist, and (for women) hip circumferences plus height. Measure consistently — same tape tension, parallel to the floor, at the specified landmarks.
Inputs
Results
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Enter measurements
Measuring like the US Navy method
Neck: just below the larynx, tape horizontal. Waist: at the narrowest point, usually near the navel level for the formula. Hip (women): at the widest part of the buttocks.
The estimate uses logarithmic circumference ratios relative to height — practical for field screening but not equivalent to DEXA or hydrostatic weighing. Very lean or very muscular people can sit outside typical ranges.
Frequently asked questions
How accurate is the US Navy tape method?
It correlates reasonably with densitometry for many service-age adults but can misclassify very muscular people, those with unusual fat distribution, or sloppy measurements.
Why might my result look unrealistic?
Wrong units, loose tape, measuring over clothing, or confusing minimum vs maximum tension on the tape can skew circumferences by centimetres—double-check inch versus cm toggles.
Is this calculator for teenagers?
The Navy regression targets adult populations; teens should use growth-chart guidance from clinicians.
Why do women enter hip circumference?
The published female equation includes hip to better capture gluteal fat patterning relative to waist and neck.
Should I dehydrate before measuring?
No. Skewing hydration to game the tape is unhealthy and defeats the purpose of tracking trends.
Are measurements uploaded?
No. Calculations stay on your device.