Estimate your body fat percentage using the U.S. Navy circumference method — one of the most practical and reasonably accurate at-home methods.
Measure neck just below the larynx, waist at the navel (men) or narrowest point (women), and hips at the widest point. Use a flexible tape and keep it level. Results are estimates — DEXA or professional calipers are more precise.
The U.S. Navy method only requires a measuring tape and height. It is widely used because it is practical, inexpensive and correlates reasonably well with more advanced methods for most people.
It estimates body fat from circumference measurements (neck, waist, and hips for women) plus height. It is a practical field method, not as precise as DEXA, but useful for tracking trends.
Rough guides: many men do well around 10–20% and many women around 18–28%, depending on age and goals. Athletes often sit lower; health risk rises at higher levels.
BMI only uses height and weight. Body fat percentage separates fat mass from lean mass, which matters for fitness, appearance and some health risks.
Every 2–4 weeks is enough for most people. Measure under similar conditions (time of day, hydration) so changes are easier to interpret.