How to Measure Body Fat

Learn 6 ways to measure your body fat and why you should it in the first place.

Ben Greenfield
4-minute read
Episode #42

How to Measure Body Fat

Now that you know what body fat percentage is and why you should measure it, here are the 6 ways you can check your body fat:

  1. Underwater weighing. Also know as hydrodensitometry, you’ll usually find this option at a university or laboratory. As the name implies, you are literally dunked underwater. While underwater, you let all the air out of your lungs and your body density is calculated. Body density can then be used to calculate body fat. Underwater weighing is considered a “gold-standard” measurement and is very accurate--but let’s face it: unless winning money at the fair is involved, who wants to strip to their skivvies and get dunked in a big tub of water?

  2. Calipers. Also known as “the pinch method,” a skinfold caliper measurement involves pinching and measuring the fat under your skin on three to seven different places on your body, and then using the thicknesses on these pinches of fat to calculate body fat percentage. Since it’s quick and convenient, you’ll often find personal trainers at gyms using these measurements. Unfortunately, unless you do many, many caliper measurements, it is easy to grab an inaccurate pinch of fat, and vastly over-or underestimate body fat, especially in overweight or obese individuals. If you use this method, make sure the person measuring you really knows what they’re doing--ask them how many times they’ve done caliper testing.

  3. DEXA. DEXA, which stands for dual energy X-Ray absorptiometry, is a full body scan usually used to measure bone density that can also be used to measure body fat and show exactly where the fat is distributed. It is one of the more costly methods of measurement and probably not an option for people who like to avoid X-ray radiation; but if you’re been diagnosed with a chronic disease related to an obese or overweight condition, you may be able to get your health insurance to cover the cost. Though less common than DEXA, other full body scanning devices that can measure body fat include Magnetic Resonance Imaging (MRI), Total Body Electrical Conductivity (TOBEC) and Computed Tomography (CT scan).

  4. NIR. In NIR (Near Infrared Interactance), a fiber optic probe is held against your skin (usually on your biceps), a painless light is used to penetrate the tissues, and the light is then reflected off your bones back into the detector, which approximates your body fat based on a prediction equation that also takes into consideration your height, weight, body type, and level of activity. Although simple and non-invasive, this method can have a high degree of error in people with very high or very low body fat percentages, and it also requires a very experienced technician. Your level of hydration and skin color can also affect the accuracy of this measurement.

  5. BodPod. An expensive, space-age looking pod that can be found at many fancier health clubs, a BodPod uses sensors to measure how much air your body displaces while you sit inside the small chamber. This information is then used to determine your body density and then estimate your body fat.

  6. BIA. Somewhat similar to NIR, BIA, which stands for analysis, sends a painless electrical signal into your body, whichpasses through fat, muscle, and water at different speeds. The speed is then combined with your sex, height, weight, and activity levels to approximate your body fat percentage. Once again, if you’re dehydrated, over-hydrated, or very skinny or very overweight, this measurement can be inaccurate--but it is very commonly used in body fat scales or handheld devices, because it is relatively inexpensive and portable.

If you find your body fat levels are higher than you’d like them to be, then try the workout found in my article: Which Workout Burns the Most Fat. And if you want more information about what type of body fat levels are realistic, then be sure to grab the free Get-Fit Guy newsletter, at http://getfitguy.quickanddirtytips.com

Caliper image courtesy of Shutterstock


All content here is for informational purposes only. This content does not replace the professional judgment of your own health provider. Please consult a licensed health professional for all individual questions and issues.

About the Author

Ben Greenfield

Ben Greenfield received bachelor’s and master’s degrees from University of Idaho in sports science and exercise physiology; personal training and strength and conditioning certifications from the National Strength and Conditioning Association (NSCA); a sports nutrition certification from the International Society of Sports Nutrition (ISSN), an advanced bicycle fitting certification from Serotta. He has over 11 years’ experience in coaching professional, collegiate, and recreational athletes from all sports, and as helped hundreds of clients achieve weight loss and fitness success.