Estimate your body-fat percentage using the US Navy circumference method — just a tape measure and your height.
The US Navy method estimates body fat from the circumference of your neck and waist (plus hips for women) relative to your height. It's free, repeatable and surprisingly close to more expensive methods.
Use a soft tape, relaxed, against the skin. Neck below the larynx; waist at the navel for men; women also measure the widest point of the hips. Measure in the morning for consistency.
Lower isn't always better — there's essential fat your body needs. Athletic ranges are roughly 6–13% (men) and 14–20% (women).
It's typically within 3–4% of a DEXA scan for most people — excellent for a free tape-measure method, and great for tracking change over time.
Every 2–4 weeks, same conditions each time. Trends matter more than any single reading.
Women carry more fat around the hips, so including that circumference makes the estimate more accurate.