Body Fat Calculator
Estimate body fat percentage with a tape measure using the U.S. Navy method, plus fat mass, lean mass and waist-to-height ratio.
What is the Body Fat Calculator?
Body fat percentage describes body composition better than weight or BMI alone.
How does it work?
The Navy method uses logarithms of neck, waist (and hip for women) circumferences and height, calibrated against underwater weighing.
Formula
Men: 495 ÷ (1.0324 − 0.19077 log(waist − neck) + 0.15456 log(height)) − 450
Example
A man 178 cm tall with a 38 cm neck and 86 cm waist has about 16–17% body fat — the “fitness” range.
Frequently asked questions
How accurate is it?
Typically within 3–4 percentage points of lab methods when measured carefully. Measure in the morning, relaxed, with the tape snug but not tight.
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