Body Fat Calculator

How to measure body fat with a tape

The U.S. Navy method estimates body fat from a few girth measurements and your height, using a formula developed by the Navy (Hodgdon & Beckett) as a field-friendly alternative to skinfold calipers or a DEXA scan. Stand relaxed and use a flexible tape, snug against the skin but not compressing it. Measure your neck just below the larynx (Adam's apple), sloping slightly downward at the front. Measure your waist at the navel for men, or at the narrowest point of the torso for women. Women also measure hips at the widest point around the buttocks — the men's formula does not use hips, which is why that field hides when Sex is set to Male. Enter your height, and the calculator applies the Navy formula automatically as you type.

The U.S. Army method

The U.S. Army tab uses the same neck, waist and height measurements but a different equation — the circumference formula from Army Regulation 600-9, which the Army uses for its own body-composition standard. It takes the same girths and returns a slightly different percentage, usually within a point or two of the Navy figure, so switching between the two tabs is a quick way to see the spread. Neither is a lab measurement; both are field estimates meant to track change over time rather than give a single exact number. If you are checking yourself against the Army standard, remember the service also applies age-based maximum limits that this calculator does not enforce.

Body fat vs BMI

BMI compares your weight to the square of your height and doesn't distinguish muscle from fat, so a muscular person and a person carrying extra fat can land on the same BMI. Body-fat percentage instead estimates what fraction of your weight is actually fat versus lean tissue (muscle, bone, organs and water), which is why it's a better read on body composition. If you want your BMI value itself — the figure this calculator's BMI method is built on — use the BMI Calculator. For just how far the two can drift apart, see why one BMI hides a 22-point body-fat gap.

Healthy body fat ranges

Using the American Council on Exercise categories that this calculator's results are tinted by: for men, essential fat is roughly 2 to 5%, athletes 6 to 13%, fitness 14 to 17%, average (acceptable) 18 to 24%, and 25% or higher is classed obese. For women, essential fat is roughly 10 to 13%, athletes 14 to 20%, fitness 21 to 24%, average (acceptable) 25 to 31%, and 32% or higher is classed obese. Women carry more essential fat than men by design, which is why the ranges differ by sex rather than sharing one scale.