How to measure body fat with a tape measure
Use a flexible cloth or vinyl tape measure. Take each measurement more than once and average the readings. Keep the tape snug but not compressed, horizontal, and parallel to the floor.
Neck
Measure just below the larynx (Adam's apple), tape slightly tilted toward the shoulders. Do not flex the neck or tense muscles.
Waist, Men
Measure at the navel (belly button level). Stand naturally, don't suck in. Take at the end of a normal exhale.
Waist, Women
Measure at the smallest circumference of the natural waist, usually between the navel and the bottom of the rib cage.
Hip, Women
Measure at the widest point of the hips, around the buttocks. Keep feet together.
Height
Stand against a wall, barefoot, heels/back/head touching wall. Have someone mark the top of your head and measure from the floor.
Body fat categories
The bands below are the American Council on Exercise (ACE) chart, a fitness-industry convention. No U.S. health agency publishes body fat categories, so they are not an official or clinical standard:
| Category | Male | Female |
|---|---|---|
| Essential fat | 2–5% | 10–13% |
| Athletes | 6–13% | 14–20% |
| Fitness | 14–17% | 21–24% |
| Average | 18–24% | 25–31% |
| Obese | 25%+ | 32%+ |
Essential fat is the fat the body needs for normal function. The chart lists whole percentages, so the calculator places your estimate by its nearest whole percentage.
The Army tape test (ABCP)
The Army Body Composition Program (ABCP, Army Regulation 600-9) sets the Army's maximum body fat for each age group and sex. In June 2023 the Army moved to a one-site tape test and said that soldiers who fail the tape may request a supplemental body fat assessment when that testing is reasonably available (U.S. Army, 12 June 2023).
This calculator uses the older multi-site equations, so its figure can differ from the Army's and it does not give a pass or fail. For the current standards and procedure, rely on the Army's own ABCP guidance.
Body fat vs BMI
BMI does not distinguish between fat, muscle and bone (CDC). Someone 5 ft 10 in tall who weighs 220 lb has a BMI of 31.6, in CDC's class 1 obesity range, whether that weight is mostly muscle or mostly fat.
CDC describes BMI as a quick screening measure of weight relative to height. A body fat estimate adds information for people carrying a lot of muscle, but from a tape or a formula it is still an estimate.
How to reduce body fat
- Lose gradually. People who lose about 1 to 2 pounds a week are more likely to keep the weight off than people who lose it faster (CDC).
- A modest loss counts. CDC notes that a 5% loss, 10 lb for someone who weighs 200 lb, could lower the risk of some chronic diseases such as heart disease, prediabetes and type 2 diabetes.
- Stay active. Adults need 150 minutes a week of moderate-intensity activity, or 75 minutes of vigorous activity or an equivalent mix, plus muscle-strengthening activity on at least 2 days a week (CDC).
- Sleep. CDC advises 7 or more hours a night for adults aged 18 to 60 (CDC).
Frequently asked questions
How do I calculate my body fat percentage?
At home, a cloth tape and a published equation give a rough figure: this page offers the older U.S. Navy circumference equations and Deurenberg's BMI-based equation. Scans such as DEXA, underwater weighing and air-displacement (Bod Pod) measure body composition more directly; some clinics, gyms and university labs offer them.
What is a healthy body fat percentage?
There is no official answer: no U.S. health agency sets body fat cut-offs. The figures most calculators quote come from the American Council on Exercise, a fitness certification body. For men its chart reads essential fat 2–5%, athletes 6–13%, fitness 14–17%, average 18–24%, obese 25%+; for women, essential fat 10–13%, athletes 14–20%, fitness 21–24%, average 25–31%, obese 32%+. Women's bands start higher because women carry more essential fat. Ask a doctor what range makes sense for you.
What is the Army tape test?
It is the circumference check behind the Army Body Composition Program, used when a soldier is over the Army's weight-for-height screening table. The Army switched to a one-site version in 2023. Since the multi-site equations on this page are no longer what the Army applies, they can't say whether a soldier would pass; the Army's own ABCP guidance can.
Where do I measure my waist for body fat?
For the Navy equations, men wrap the tape around the abdomen level with the navel, and women around the narrowest part of the natural waist. Keep it level and snug without pressing into the skin, read it after breathing out normally, and repeat a few times, averaging the readings.
Is body fat percentage more accurate than BMI?
They answer different questions. BMI relates weight to height and cannot tell fat from muscle or bone, which CDC points out. A body fat estimate tries to split fat from everything else, so it says more for a heavily muscled person, but a tape or BMI-based figure is itself only an estimate and can be well off for an individual.
What is the Navy body fat formula?
Hodgdon and Beckett at the Naval Health Research Center published it in 1984, and the Defense Department later applied it across the services. Men: % fat = 86.010 × log10(abdomen − neck) − 70.041 × log10(height) + 36.76. Women: % fat = 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387. Every measurement is in inches. It was fitted to Navy personnel, so it is least reliable for people unlike them, such as the very lean or heavily muscled.
What body fat percentage can you see abs?
No official or reliable figure exists. Whether abdominal muscles show depends on how developed they are and where your body stores fat, not only on the total, so two people with the same estimate can look quite different. A tape estimate is also too rough to aim at a visual threshold.
How does age affect body fat standards?
No health agency sets age-based body fat standards for the public. Age does enter the BMI-based equation: at the same BMI, Deurenberg's formula adds 0.23 percentage points for each extra year, as body fat was higher in the older people it was fitted to. The Army sets its own maximums by age group, which this calculator does not check.
Can you fail the Army body fat test?
Yes. A soldier over the Army's limit is flagged. Under the guidance issued in June 2023, one who fails the tape may ask for a supplemental body fat assessment where such testing is reasonably available. The consequences and timelines are set out in Army regulation AR 600-9 and later directives, not on this page.
How often should I measure body fat?
No official schedule exists. Tape readings shift with hydration, meals and small changes in where the tape sits, so a change from one day to the next means little. Measure under the same conditions each time, at the same time of day and the same tape positions, and watch the trend over weeks.