Body Fat Percentage Calculator

Body fat percentage at a glance#

Body fat percentage is the share of your total body weight that is fat, as opposed to muscle, bone, organs and water. The calculator above estimates it two ways: the US Navy circumference method, which uses your tape measurements, and a BMI-based method, which uses height, weight, age and gender. Both give a ballpark figure, usually within about 3.5 to 5 percent of a clinical measurement.

How to calculate body fat#

The US Navy method needs your height, neck and waist measurements, and women also measure the hips. It compares the waist (and hips) against the neck and height: a larger waist relative to neck and height returns a higher body fat estimate. The BMI-based method instead derives the estimate from your height, weight, age and gender. For either one, measure first thing in the morning, before eating, and keep the tape level and snug but not tight, since clothing, hydration and meal timing all shift the reading.

Body fat categories#

Once you have a number, these American Council on Exercise ranges show where it sits. Women carry more essential fat than men for hormonal and reproductive reasons, so every band is higher for women.

Enter your measurements in the calculator above for your estimated body fat percentage, lean body mass and fat mass. These are estimates, not lab results, so treat the category as a guide and track the trend over time rather than a single reading.

Why body fat percentage beats weight alone#

Body fat percentage tells you how much of your weight is fat versus muscle, bone and water, which your scale weight and BMI cannot. Two people at the same weight can have very different bodies: one lean and muscular, one carrying more fat. Tracking the percentage shows if you are losing fat or losing muscle when you diet, so it is a better progress metric than weight on its own.

Essential and storage fat#

Some body fat is necessary. Essential fat supports hormones, cell membranes and organ protection, and women need more of it than men for reproductive function, which is why the healthy ranges are higher for women. Storage fat is the energy reserve under the skin and around the organs. Too little fat disrupts hormones and immunity; too much, especially around the abdomen, raises the risk of heart disease, type 2 diabetes and high blood pressure. The category table in the answer block above shows the healthy bands.

Ways to measure body fat#

Methods trade accuracy for cost and convenience:

• Tape (circumference) method: free and at home; the US Navy version used by the calculator above is usually accurate to within about 3.5 percent.
• Skinfold calipers: cheap but depend on the tester's skill; take three readings per site and average them.
• Bioelectrical impedance (BIA) scales: quick, but readings shift with hydration and often underestimate fat.
• DEXA scan and hydrostatic weighing: the most accurate, with error rates around 2 to 5 percent, but they cost more and need a clinic.

For tracking at home, pick one method and use it the same way each time. The trend over weeks matters more than any single number.

Measuring for an accurate estimate#

If you use the tape method, measure in the morning before eating or drinking, with the tape level and snug but not compressing the skin. Men measure neck and waist; women add the hips. Stand straight for the height measurement, heels and shoulders against a wall, looking ahead. Hydration, recent meals and clothing all move the result, so keep the conditions consistent between checks.

An estimate, not a lab result#

A calculator gives a ballpark, usually within about 5 percent of a clinical measurement for most people, and it is least reliable at the extremes of very low fat with high muscle or very high fat. Use it to watch your own trend and to set realistic goals, not as a precise medical figure. For a clinical reading, a DEXA scan is the more accurate option.

Frequently asked questions#

What is a good body fat percentage?#

It depends on age and sex. As a rough guide, fitness-level men sit around 14 to 17 percent and women around 21 to 24 percent. The full essential, athlete, fitness, average and obese bands are in the category table above.

How do I measure my body fat percentage?#

Options include the tape (circumference) method, skinfold calipers, bioimpedance scales, DEXA scans and hydrostatic weighing. The calculator above uses the tape method, which you can do at home with a measuring tape.

Which method is most accurate?#

Hydrostatic (underwater) weighing and DEXA scans are the most accurate, with error rates around 2 to 5 percent. They are also the most expensive and least accessible, so most people use a tape or skinfold estimate to track change.

How is this different from BMI?#

BMI uses only weight and height and cannot separate fat from muscle. Body fat percentage estimates the fat portion of your weight directly, so it gives a clearer picture for athletic or muscular people.

Why does body fat percentage matter?#

It distinguishes fat from muscle, so it is a more specific health signal than weight or BMI. Levels that are too high or too low both carry health risks, which is why the healthy range sits between the extremes.