You can determine your body fat percentage using methods that range from a tape measure and a simple formula to clinical scans that cost a few hundred dollars. The right choice depends on whether you need a precise number or just want to track changes over time. Each method has trade-offs between accuracy, cost, and convenience.
What Counts as a Healthy Body Fat Percentage
There is no universally agreed-upon normal range for body fat, but a large 2025 study using U.S. national survey data offers useful benchmarks. It defined “overweight” as body fat of at least 25% for men and 36% for women. “Obesity” started at 30% for men and 42% for women. These thresholds reflect metabolic risk rather than appearance, and they shift with age. Older adults naturally carry more fat, so a 55-year-old at 28% body fat isn’t in the same risk category as a 25-year-old at the same number.
Keep in mind that total body fat is only part of the picture. Fat stored deep around your organs, called visceral fat, is far more dangerous than the fat just under your skin. Visceral fat actively releases inflammatory compounds that drive insulin resistance, high blood pressure, and cardiovascular disease. About 20% of men and 10% of women with a normal waist circumference still have elevated visceral fat, which means you can look lean and still carry metabolic risk. Only certain measurement methods can distinguish between these two types of fat.
The Tape Measure Method
The simplest way to estimate body fat at home is the U.S. Navy circumference method. You need a flexible tape measure and your height. For men, measure your waist at the navel and your neck just below the larynx. For women, an additional hip measurement is taken at the widest point. These numbers go into a logarithmic formula that estimates body fat percentage based on the relationship between your frame size and where you carry weight.
You don’t need to do the math yourself. Dozens of free online calculators accept these three or four measurements and return an estimate in seconds. The method won’t rival a clinical scan for precision, but it’s repeatable and costs nothing. If you measure the same way each time (same posture, same tension on the tape, same time of day), it becomes a reliable tool for tracking whether your body fat is going up or down over weeks and months.
Bioelectrical Impedance Scales
Smart scales and handheld devices that estimate body fat use bioelectrical impedance analysis, or BIA. They send a weak electrical current through your body and measure how quickly it passes through. Fat slows the signal down because it contains less water than muscle, so the device estimates your fat percentage based on resistance.
BIA is convenient but highly sensitive to your hydration level. Drinking a large amount of water, exercising intensely, or taking a hot shower right before stepping on the scale can all shift your reading significantly. For the most consistent results, measure first thing in the morning before eating or drinking anything. Even with perfect consistency, BIA readings can vary by 5% to 10% from your true body fat percentage. That means if a DEXA scan puts you at 22%, your bathroom scale might read anywhere from 12% to 32% on a bad day, though the error is typically smaller than that extreme range.
The real value of a BIA scale is trend tracking. If you weigh yourself under the same conditions every morning, the absolute number matters less than whether it’s moving in the right direction over time.
Skinfold Calipers
Skinfold testing uses a spring-loaded caliper to pinch and measure the thickness of fat beneath the skin at specific body sites. A common protocol for men measures the chest, abdomen, and thigh. For women, the standard three sites are the triceps (back of the upper arm, halfway between the shoulder and elbow), the area just above the hip bone, and the thigh. A more thorough seven-site test adds the chest, midaxillary (side of the torso), subscapular (below the shoulder blade), and additional locations.
When performed by an experienced tester, skinfold measurements are reasonably accurate and very affordable. A quality set of calipers costs $10 to $30. The catch is technique: you need to pinch the exact right spot, pull the fold away from the muscle, and read the caliper correctly. Self-testing is possible at some sites (like the abdomen) but awkward at others (like the subscapular). If you’re doing this at a gym, consistency matters more than the tester’s credentials. Having the same person measure you each time eliminates the biggest source of error.
DEXA Scanning
Dual-energy X-ray absorptiometry is the clinical gold standard for body composition. You lie on a padded table for about 10 minutes while a low-dose X-ray arm passes over your body. The scan distinguishes bone, lean tissue, and fat with a precision of roughly 1%, far tighter than any home method.
What makes DEXA particularly useful is regional data. You don’t just get a single body fat number. You see how fat and muscle distribute across your arms, legs, trunk, and visceral region. This means DEXA can flag dangerous visceral fat that a tape measure or scale would miss entirely. Ultrasound can also assess visceral fat and is noninvasive and relatively inexpensive, but it’s less commonly available for general body composition testing.
A body composition DEXA scan typically costs $40 to $200 at wellness centers and mobile scan providers, or $150 to $400 at hospital-based facilities. Insurance rarely covers scans done purely for body composition (as opposed to bone density screening). Mobile scan providers that bring equipment to gyms and health events often charge $65 to $150 per scan and are worth looking into if cost is a concern.
How to Prepare for Accurate Results
Regardless of which method you choose, preparation affects your results. Clinical guidelines for DEXA scans call for fasting 8 to 12 hours beforehand, avoiding exercise for 24 hours, skipping caffeine for 24 hours, and getting a full night of sleep. On the morning of the scan, stay fasted and drink only a small amount of water to maintain hydration. Anything with calories can skew the reading.
These same principles apply to BIA scales and skinfold testing, even if the stakes are lower. Exercise redistributes fluid and increases blood flow to the skin, both of which distort readings. Eating a large meal adds weight that isn’t fat. Dehydration makes BIA scales overestimate your body fat because less water in your tissues mimics the electrical resistance of fat. The simplest rule: test first thing in the morning, fasted, before your workout, and wear minimal clothing.
Choosing the Right Method for Your Goals
If you want a single accurate snapshot of your body composition, including where your fat sits and whether your visceral fat is elevated, a DEXA scan is worth the investment once or twice a year. If you want to track daily or weekly trends at home, a BIA scale used under consistent conditions gives you useful directional data even though the absolute number may be off. The Navy tape measure method is the best free option and surprisingly informative when done consistently.
For most people, combining two methods works well. Use a home method weekly to watch the trend, and get a DEXA scan every six to twelve months to calibrate your understanding of what those home numbers actually mean. No single method is perfect, but consistency with any method tells you whether what you’re doing is working.