Body fat percentage tells you what your weight is actually made of. Enter four tape measurements and this calculator estimates your body fat, your lean mass, and where you sit against published ranges.
Estimate from the U.S. Navy circumference method, accurate to roughly plus or minus 3 to 4 percent against hydrostatic weighing. It is a screening estimate, not a diagnosis.
The estimate is only as good as the tape work. Use a flexible cloth tape, keep it level and snug without compressing the skin, and take each measurement twice. If the two readings disagree, measure a third time and use the middle value.
Measure just below the larynx, with the tape sloping slightly downward at the front. Keep your shoulders down and do not flex. Round down to the nearest half unit.
Men measure at the navel. Women measure at the narrowest point of the torso. Take the reading at the end of a normal breath out, without pulling the tape tight.
Women only. Measure the widest point of the hips and buttocks, with the tape level all the way round and your feet together.
Stand against a wall without shoes, heels together, looking straight ahead. Measure to the highest point of the head.
The minimum needed for hormone production, temperature regulation and organ protection. Below this range is not a goal, it is a medical risk.
Typical of people training seriously most days of the week, usually with a diet built around that training.
A lean, sustainable range for most people who exercise regularly. This is a realistic target rather than a competitive one.
The usual range for healthy non-athletes. Plenty of people are in good metabolic health here.
Associated with higher risk of type 2 diabetes, cardiovascular disease and metabolic syndrome. Worth a conversation with a provider.
Source: American Council on Exercise general body-fat percentage categories. Ranges are most often quoted for adults aged 20 to 39 and are not diagnostic on their own.
BMI is weight divided by height squared. It knows nothing about what the weight is made of, so a muscular person can register as overweight while someone at a normal BMI carries enough visceral fat to be at real metabolic risk. It is useful for population statistics and a blunt instrument for individuals.
Body fat percentage separates fat mass from lean mass, which is the distinction that actually matters for metabolic health, hormone function and how you should train and eat. It also tracks progress far better. During a weight loss program the scale can stall for weeks while body composition keeps improving.
Body composition is one input. A consultation covers your labs, your hormone panel and your history, and turns an estimate into a plan you can actually follow.
