Body Fat Calculator (Tape Method)

The tape-measure method, often called the US Navy formula, estimates body fat from the circumference of a few sites rather than from a scale. The idea is that fat is stored around the trunk, waist and hips, so the ratio of those measurements to your height and neck predicts what share of your body is fat. It is nowhere near as accurate as a DEXA scan, but it costs nothing, needs only a soft tape, and is far more informative than body weight alone.

Measure with the tape snug but not compressing the skin, and keep it level all the way around. Men measure the neck just below the larynx and the waist at the navel. Women measure the neck the same way, the waist at the narrowest point, and the hips at the widest point around the buttocks. Take each measurement two or three times and use the average; a single slip of a centimetre can shift the result by a percentage point.

The formulas themselves are logarithmic, which means small waist changes matter more for people who already carry little fat, and less for those with more. For men the input is waist minus neck; for women it is waist plus hip minus neck. That is why a receding waistline moves the number so quickly for anyone who is leaning out: dropping two centimetres off the waist can trim roughly half a percentage point.

Interpret the result as a trend, not an absolute truth. Aim to measure in the same conditions — first thing in the morning, before eating, with the tape in the same spot — and watch the direction over weeks. Healthy ranges sit around 8–19% for men and 21–32% for women, with women naturally carrying more essential fat. If you are tracking fat loss, the fat-mass and lean-mass rows tell you whether the weight you are losing is coming from fat or from muscle.

This calculator returns estimates for general information only. It is not medical advice, diagnosis or treatment, and it cannot replace an assessment by a qualified health professional. Individual results vary, and figures such as calorie needs, body-fat percentage and heart-rate zones are approximations based on population averages rather than measurements of you.