Body Fat Calculator
Estimate your body fat percentage from a few tape measurements using the US Navy method, and see your fat and lean mass. It is a trend tracker, not a body scan.
The US Navy tape method estimates body fat from measurements, not a body scan. It is a useful trend tracker, give or take a few points.
How the tape method works
Measure with a snug, level tape. Neck below the larynx, waist at the navel, hips at the widest point. The US Navy formula uses the log of those circumferences with your height:
Men: 495 / (1.0324 - 0.19077 x log(waist - neck) + 0.15456 x log(height)) - 450
Women add the hip: log(waist + hip - neck)
Body fat bands (ACE): for men, athlete 6 to 13%, fitness 14 to 17%, average 18 to 24%. For women each band sits about 8 points higher.
Source: Hodgdon and Beckett, US Navy (1984); American Council on Exercise body-fat norms.
Frequently asked questions
How accurate is the tape method?
For most people it lands within a few percentage points of a DEXA or hydrostatic scan, which is enough to track a trend. What matters is measuring the same way each time, so the direction is honest even if the absolute number is a little off.
Where exactly do I measure?
Use a snug, level tape. Measure your neck just below the larynx, your waist at the navel, and for women the hips at the widest point. Do not pull the tape tight enough to compress the skin, and measure at the same time of day.
Body fat percentage vs BMI, what is the difference?
BMI only uses height and weight, so a muscular person can read as overweight. Body fat percentage estimates how much of your weight is actually fat, which is why a lean athlete and an inactive person at the same BMI can be very different.
What is a healthy body fat percentage?
By the ACE ranges, the fitness band is roughly 14 to 17% for men and 21 to 24% for women, with athletes lower and essential fat as the floor. There is no single ideal number, and very low body fat carries its own risks.
Does this save my measurements?
No. The calculator runs entirely in your browser and nothing you type is stored or sent anywhere. Refreshing the page clears it.
Medical disclaimer: This calculator is for general information and education only. It is an estimate, not medical advice, diagnosis or treatment. Always talk to your doctor or midwife about your health and any decisions.