You can get your body fat percentage measured through several methods, ranging from a free tape-measure calculation at home to a clinical scan costing $40 or more. The right choice depends on how precise you need the number to be and whether you’re tracking changes over time or just want a baseline. Here’s how each method works, what it costs, and how accurate it really is.
Smart Scales and Bioelectrical Impedance
The most accessible option is a smart scale that uses bioelectrical impedance analysis, or BIA. These scales send a small, harmless electrical current through your body and measure the resistance. Because muscle and fat conduct electricity differently, the scale estimates how much of your weight comes from fat.
The convenience is hard to beat: step on, wait a few seconds, and get a reading. But BIA is the least precise method on this list. Your hydration level, how recently you ate, the temperature of the room, and even how you place your feet on the scale can all shift the number. If you’re dehydrated, the scale may overestimate your body fat. If you just drank a large amount of water, it may underestimate it. A quality BIA scale costs $25 to $100, and while the absolute number it gives you may be off, it can still be useful for tracking trends if you weigh yourself at the same time of day under the same conditions.
The US Navy Formula
If you want a no-cost estimate right now, the US Navy body fat formula uses a tape measure and some basic math. Men need three measurements: neck circumference, waist circumference, and height. Women need four: neck, waist, hip, and height.
For the neck, measure at the base, just below the Adam’s apple. For the waist, measure at the narrowest point above your hip bones (for most men, this is at the navel). Women also measure the hips at the widest point of the glutes, standing with feet together. Plug those numbers into one of the many free online Navy body fat calculators. The formulas use logarithmic equations, so doing them by hand isn’t practical, but any calculator handles it instantly.
This method is a rough estimate. It doesn’t account for muscle mass very well, so a muscular person with a thick waist will get an inflated reading. But it’s free, repeatable, and good enough for a ballpark figure.
Skinfold Calipers
Skinfold testing involves pinching folds of skin and fat at specific body sites and measuring their thickness with calipers. The most thorough version, the Jackson-Pollock 7-site protocol, takes measurements at the chest, abdomen, thigh, tricep, subscapular (below the shoulder blade), suprailiac (above the hip bone), and midaxillary (side of the torso). A simpler 3-site version uses a subset of those locations.
A basic personal caliper costs $10 to $20. Professional-grade models like the Harpenden caliper run $300 or more, but that’s really a tool for trainers and clinics. The catch is technique: accuracy depends heavily on the person doing the pinching. If you test yourself, your readings will be less consistent than if a trained professional does it. That said, once you learn the sites and practice, calipers are a solid, affordable way to track changes in subcutaneous fat (the fat just under your skin) over weeks and months.
Bod Pod (Air Displacement)
A Bod Pod is an egg-shaped chamber that measures your body volume using air displacement. You sit inside for two to three 50-second periods while the machine calculates the volume of air your body displaces. Combined with your weight from a precise electronic scale, the system calculates your body density and converts it to a fat percentage. The whole process takes about 10 minutes.
The Bod Pod is considered as accurate as underwater (hydrostatic) weighing, which was long the gold standard. Its margin of error is plus or minus 1 to 2.7 percentage points. A single session typically costs $45 to $75. You’ll find Bod Pods at university exercise science labs, sports performance centers, and some health clinics. It’s a strong middle-ground option: more accurate than a scale or calipers, less expensive than repeated imaging scans.
DEXA Scan
A DEXA scan (dual-energy X-ray absorptiometry) is the most detailed option widely available to consumers. You lie on a table while a low-dose X-ray arm passes over your body, distinguishing fat tissue, lean mass, and bone. The scan takes about 10 to 15 minutes and produces a regional breakdown, so you can see exactly how fat is distributed across your arms, legs, and trunk.
Beyond total body fat percentage, a DEXA report includes visceral fat (the deeper fat packed around your organs), skeletal muscle mass, bone density, resting metabolic rate, and ratios that compare your upper-body and lower-body fat distribution. That level of detail is why DEXA is popular with athletes and anyone serious about body composition. A scan typically starts around $40, though prices vary by location. You can find DEXA at radiology clinics, sports medicine facilities, and mobile scanning services.
One important limitation: despite its precision, DEXA cannot distinguish between visceral fat and subcutaneous fat in the same region. It estimates visceral fat in the abdominal area, but if you need a truly detailed map of fat compartments, CT or MRI scans are the only methods that can separate those layers. Those imaging methods are expensive and rarely used for routine body composition testing.
What the Numbers Mean
Once you have a body fat reading, you need context. The American Council on Exercise classifies body fat into broad categories. For women, 25% to 31% is typical for an average non-athlete, while 21% to 24% falls in the fitness range. Female athletes generally carry 14% to 20%. Below 14% in women is considered dangerously low and carries health risks including hormonal disruption and bone loss.
For men, 18% to 24% is average, 14% to 17% falls in the fitness category, and athletes typically range from 6% to 13%. Below 6% in men is similarly risky. Essential fat, the minimum your body needs to function, accounts for about 10% to 13% in women and 2% to 5% in men. These ranges exist because women carry more essential fat for reproductive and hormonal functions.
Picking the Right Method for Your Goals
If you just want a general idea of where you stand, the Navy formula or a BIA smart scale will get you in the right neighborhood for free or close to it. If you’re starting a structured training or nutrition program and want to track real changes, calipers or a Bod Pod give you more reliable data to compare over time. If you want a comprehensive snapshot of your body composition, including regional fat distribution and muscle mass, a DEXA scan is the best widely available option.
Whichever method you choose, consistency matters more than precision. Use the same method, the same device or facility, and test under the same conditions each time. A BIA scale that’s off by 3 percentage points can still show you a meaningful trend if you always step on it first thing in the morning before eating.
How Often to Retest
Body composition changes slowly, and testing too frequently turns normal daily fluctuations into false signals. If you’re actively working to lose fat, retesting every 4 to 6 weeks gives your body enough time to show measurable change. If you’re focused on building muscle, every 6 to 8 weeks is more appropriate since lean mass accumulates gradually. If you’re maintaining your weight or just checking in periodically, every 2 to 3 months is plenty. The goal is to track trends across multiple data points, not to react to any single reading.