How to Measure Body Fat Percentage at Home
November 9, 2026
Body fat percentage is the share of your body weight that is fat. Unlike BMI, which only uses height and weight, it tries to separate fat from muscle, bone and water. No home method measures it directly, but a tape measure, used carefully and consistently, gives a useful estimate and a good way to track change.
This guide is general information, not medical advice. Body fat is one measure among many, and a clinician can put yours in context.
Ways to estimate body fat
- Tape measure (U.S. Navy method). Uses your height and a few circumferences. Cheap and repeatable, and the method this guide explains. Results depend on measuring the same way every time.
- Skinfold calipers. Pinch the skin at set points and plug the thicknesses into a formula. Accuracy depends heavily on the skill of the person measuring.
- Smart scales (bioelectrical impedance). Send a weak current through the body. Readings shift with hydration, so a scale can show a different number in the morning and evening of the same day.
- DXA scans. An X-ray method used in research and some clinics. It's one of the more accurate options, but it costs money and needs a clinic.
- BMI. Not a body fat measure. The CDC notes BMI doesn't distinguish fat from muscle or bone, so a muscular person can have a high BMI and low body fat.
The U.S. Navy tape method
The method was published by Hodgdon and Beckett for the U.S. Navy in 1984. It predicts body density from your height and circumferences, then turns density into a body fat percentage. You need a flexible tape measure and about five minutes.
Taking the measurements
- Height. Stand straight against a wall without shoes.
- Neck. Measure just below the larynx (Adam's apple), with the tape sloping slightly down toward the front.
- Waist. Men measure around the abdomen at the navel. Women measure at the narrowest point of the waist.
- Hips (women only). Measure around the widest part of the buttocks.
Keep the tape flat against the skin, snug but not compressing it. Measure at the end of a normal breath out, with your stomach relaxed rather than pulled in. Take each measurement three times and use the average.
The formulas
In centimeters, with log10 meaning the base-10 logarithm:
- Men: 495 / (1.0324 − 0.19077 × log10(waist − neck) + 0.15456 × log10(height)) − 450
- Women: 495 / (1.29579 − 0.35004 × log10(waist + hip − neck) + 0.22100 × log10(height)) − 450
Logarithms are tedious by hand, so the body fat calculator does the arithmetic.
Worked examples
A woman, measured in centimeters. She is 165 cm tall, with a 33 cm neck, a 74 cm waist and 98 cm hips. The formula gives 27.9% body fat, in the Average category. At 62 kg that's about 17.3 kg of fat.
A man, measured in inches. He is 5 ft 10 in tall, with a 15-inch neck and a 34-inch waist. In centimeters that's 177.80, 38.10 and 86.36. The formula gives 17.4% body fat, in the Fitness category. Use the inches to cm converter if your tape is in inches.
The second example shows why consistent measuring matters. If the same man's waist measures 33 inches instead of 34, the result drops to 15.5%. One inch of tape is about two points of body fat.
What the categories mean
The American Council on Exercise (ACE) groups body fat percentages like this. The categories describe fitness groups, not health diagnoses.
| Category | Men | Women |
|---|---|---|
| Essential fat | 2–5% | 10–13% |
| Athletes | 6–13% | 14–20% |
| Fitness | 14–17% | 21–24% |
| Average | 18–24% | 25–31% |
| Obese | 25% and up | 32% and up |
Women carry more essential fat than men, which is why every range is higher.
How accurate is the tape method?
It's an estimate. In a 2022 study of fit U.S. Marines compared with DXA scans, the Navy method read about 2.5 points low for men on average and 1 to 2 points high for women. It tended to overestimate body fat in lean people and underestimate it in people with more body fat. Errors for individuals can be larger, and Marines aren't typical of the general public.
It was developed with adult Navy personnel, so it isn't suited to children or to pregnancy.
Tips for tracking change
- Measure at the same time of day, ideally in the morning before eating.
- Use the same tape and, if someone helps you, the same person.
- Look at the trend, not a single reading. A change of a point or so can be measuring noise.
- Pair it with another measure. Waist size on its own, or the waist-to-hip ratio calculator, tells you about fat around the middle, which is the kind most linked to health risks.
Related tools
- BMI. The BMI calculator is a quick screening measure, with the limits above.
- Energy needs. See what BMR is and how to work it out.