Body Fat & Lean Mass Estimator
Scale weight cannot tell fat from muscle. This estimator uses the US Navy tape method to gauge your body-fat percentage, fat mass, and lean mass from a few measurements.
Measured just below the larynx.
At the navel.
Estimated composition
Body fat
17.4%
US Navy tape estimate. Less precise than DEXA.
Lean mass
148.6lb
Everything that is not fat: muscle, bone, water.
How this works
The US Navy method estimates body-fat percentage from tape measurements and height using a logarithmic formula (measurements in centimetres):
men: BF% = 495 / (1.0324 - 0.19077 x log10(waist - neck) + 0.15456 x log10(height)) - 450
women: BF% = 495 / (1.29579 - 0.35004 x log10(waist + hip - neck) + 0.22100 x log10(height)) - 450
From there, fat mass is your weight times body-fat percentage, and lean mass is what remains:
fat mass = weight x BF% / 100
lean mass = weight - fat mass
The imperial toggle converts inches to centimetres and pounds to kilograms before the formula runs. This is a tape-based estimate and is less accurate than a DEXA scan, so measure the same way each time and watch the trend. To go deeper, read body composition tracking on a GLP-1 and how to read a DEXA scan.
Frequently asked questions
How does the US Navy body fat method work?
It estimates body-fat percentage from a few tape measurements (neck, waist, and hip for women) plus height, using a logarithmic formula validated against more precise methods. It is convenient but it is still an estimate.
How accurate is a tape-based estimate?
Tape methods are repeatable and free, but less accurate than a DEXA scan. Use the same technique each time and watch the trend rather than fixating on a single number.
What is lean mass?
Lean mass is your weight minus fat mass: muscle, bone, organs, and water. On a GLP-1, holding lean mass while fat mass falls is the goal, which is exactly what Myo helps you track over time.
Related tools
Related reading
Track it, do not just calculate it
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