Body Fat Calculator

Flexible tape, snug but not compressing skin. Waist: at the navel, relaxed — not sucked in, not pushed out. Neck: just below the larynx, tape sloping slightly down to the front. Hips (women): at the widest point. Same time of day each time, ideally morning; consistency matters more than perfection.

Studies put it within about 3–4% of DEXA for most people — genuinely respectable for a tape measure. It drifts most for very muscular builds (thick necks help the formula flatter you) and very lean ones. Consumer bioimpedance scales are often worse and swing several percent with hydration alone.

Healthy, sustainable ranges for most adults: roughly 10–20% for men and 18–28% for women, with athletes lower and 'essential' fat (~3% men, ~12% women) being a physiological floor, not a goal. Very low percentages carry hormonal and performance costs that photos don't show.

It answers a different question. BMI is weight-for-height and can't tell muscle from fat — a muscular lifter scores 'overweight'. Circumference-based body fat looks at where mass sits, which is more informative for individuals. Best practice is tracking the trend of either metric, not worshiping a single reading.