Body Fat Calculator

Each method in this calculator offers a different trade-off between accessibility and accuracy. The US Navy circumference method requires only a measuring tape and delivers results within 3 to 4 percent of DEXA scans for most non-extreme body types — a level of accuracy that is clinically useful for tracking changes over time, even if the absolute number is off by a few points. The Jackson-Pollock three-site and seven-site skinfold methods offer somewhat higher precision for trained testers, but require calipers and careful, repeatable technique; measurement error at a single skinfold site can shift results by 2 to 3 percent.

The BMI-based estimate is the least accurate because it makes no distinction between muscle and fat, but it requires no equipment whatsoever. It is useful as a rough screening tool for untrained populations or to generate a plausible initial estimate before investing in more careful measurement. Regardless of which method you use, the most valuable practice is consistency: measure using the same method, the same time of day, and the same hydration state each time, and track the trend rather than treating any single reading as a definitive answer.

Where you carry fat matters clinically as much as the total percentage. Visceral fat — the fat stored around and within the abdominal organs — is metabolically active in harmful ways. It secretes pro-inflammatory adipokines, contributes to insulin resistance, and is independently associated with elevated cardiovascular disease risk, type 2 diabetes, and non-alcoholic fatty liver disease. Two people with identical total body fat percentages can have dramatically different health risk profiles if one carries most fat viscerally and the other subcutaneously.

Subcutaneous fat stored in the hips, thighs, and buttocks carries far lower metabolic risk and in some studies is associated with protective effects on insulin sensitivity. The waist circumference and waist-to-hip ratio capture visceral fat burden in ways that total body fat percentage cannot. A waist circumference above 40 inches (102 cm) in men and above 35 inches (88 cm) in women is considered a high-risk threshold by most clinical guidelines, independent of BMI or total body fat. Tracking waist circumference alongside your body fat percentage gives a more complete picture of metabolic health than either number alone.

Sustainable fat loss occurs at a rate of roughly 0.5 to 1 percent of total body weight per week — faster than this and you begin losing significant lean mass alongside fat. In terms of body fat percentage, most people can realistically expect to drop 0.5 to 1 percentage point per month under a well-designed diet and training program. This means moving from 28 percent to the fitness range of 20 to 24 percent takes roughly four to eight months of consistent effort — not four to eight weeks.

For most people, aiming for the fitness range rather than the athletic range is both more achievable and more sustainable. Maintaining very low body fat (under 10 percent for men and under 18 percent for women) requires strict dietary adherence and can impair hormonal function, immune response, bone density, and athletic recovery. Take measurements monthly rather than weekly to avoid being misled by normal day-to-day fluctuations in hydration, glycogen storage, and measurement technique — which can shift apparent body fat by 2 to 3 percentage points over a single week without any real change in fat tissue.