The Body Fat Calculator estimates the share of your body weight that is fat. It offers three methods, so you can use whichever measurements you have to hand.

The three methods

Tape (U.S. Navy): uses a tape measure around your neck and waist (and hips for women) plus your height. It needs no special equipment and is the most practical way to track body fat at home. Keep the tape level and snug but not tight — neck just below the larynx, waist at the navel for men and the narrowest point for women, hips at the widest part.

Skinfold (Jackson–Pollock 3-site): uses calipers to pinch the skinfold at three sites — chest, abdomen and thigh for men; triceps, suprailiac and thigh for women — plus your age. With careful technique it is one of the more accurate at-home methods.

BMI method (Deurenberg): estimates body fat from your Body Mass Index, age and gender. It needs only height and weight, but is the least precise because it cannot tell muscle from fat.

What the categories mean

Results follow the American Council on Exercise (ACE) ranges, which differ for men and women: Essential fat (the minimum needed for health), Athletes, Fitness, Average (acceptable), and Obese. Women naturally carry more essential fat than men, so their healthy ranges are higher.

Fat mass and lean mass

If you enter your weight, the calculator also splits it into fat mass (weight × body fat %) and lean body mass (everything else — muscle, bone, organs and water). Watching lean mass is useful when dieting, to make sure you lose fat rather than muscle.

How accurate is it?

All three are estimates, not precise measurements like a DEXA scan or hydrostatic weighing. Accurate, consistent technique matters most — measure the same way each time and watch the trend rather than a single number. For anything important, consult a doctor. Nothing you enter is uploaded — the calculation runs entirely in your browser.