Scales which calculate body fat

Known as body-fat scales, some also calculate your body mass index, or BMI, which measures your weight in relation to your height. And still others allow you to upload all of that information to your smartphone or computer, so you can track changes in your weight and other measurements over time, and if you choose, share your progress with your workout buddies.

We took note of which models had which features, talked with weight-loss experts to learn how important it is to have those extras, then did some tests to find out how well the main features worked.

We checked first to see how well they performed the most basic function: giving users an accurate weight. To do that, we had seven men and eight women step on an electronic lab scale, which we used as a control, then weighed them four times over two days on each of the scales.

Five of the body-fat scales read weight accurately, but one, the Qardio QardioBase which happened to be one of the priciest , routinely overestimated weight by 6 to 10 pounds. When we asked Qardio to respond to our findings, the company told us that it was aware of the problem and said it was corrected. Consumer Reports investigated Qardio's fix; here's what we found. Customers can ask for a refund or replacement at support getqardio. For more details on all six scales, check our Ratings and buying guide.

Rating a body-fat scale on its ability to gauge body fat was more complicated, and the results were unimpressive: None was very accurate. We know that because we got benchmark readings by using a measuring tool called a Bod Pod at Sacred Heart University in Fairfield, Conn.

Six volunteers—three men and three women, some heavier, some slimmer—climbed into the Bod Pod. The egg-shaped device determines body fat by precisely recording the change in air pressure created when a body is sealed into a closed chamber.

Research shows that method is as accurate as the other gold standard—measuring how much water a body displaces when dunked into a tank full of water—but the Bod Pod measure is quicker and easier to perform.

That tiny current—much too low to feel or cause any harm—passes up one leg, through your pelvis, and down your other leg. The resistance the current encounters as it travels depends on the proportion of fat and muscle tissue.

Based on that, the scales use built-in formulas to estimate the percentage of your weight that comes from fat. For some of our test subjects, the scales overstated their body fat; for others, the scales understated it.

The body-fat scale that came closest to the Bod Pod results was still off by up to 21 percent; the worst performer was off by up to 34 percent. At least they were consistent, though, so you can use the scales that scored better at body-fat repeatability to track relative gains and losses over time.

How a device errs may depend in part on body shape. Because the electric current passes through only your legs, the scales might underestimate body fat if you have a big belly but slimmer legs and overestimate it if you carry more weight on your hips and thighs. Results can also vary depending on whether your feet are wet or dry they should be dry, according to the instructions , whether you recently exercised, and how much water you had to drink.

Or you could just use a measuring tape and a calculator. To calculate your BMI, divide your weight in pounds by your height in inches squared; then multiply by For example, a pound, 5-footinch person has a BMI of Certain BMI scales we looked at will do that calculation for you.

The resistance the current encounters as it travels depends on the proportion of fat vs. Based on that, the scales use built-in formulas to estimate the percentage of your body weight that comes from fat. Here are a few that Amazon reviewers rave about.

For access to exclusive gear videos, celebrity interviews, and more, subscribe on YouTube! In order to view the gallery, please allow Manage Cookies. Sponsored content Once upon a time, the lower the number on the bathroom scale, the better shape you were in. More Videos. Shop online for body fat scales. In general, body fat scales can provide rough estimates only.

While safe to use, there are many variables that can affect your results. These include:. The greatest benefit to using this type of scale is that you can measure your body fat in the comfort of your own home at any time, all without having to travel to a gym or clinic. Body mass index BMI is perhaps a more reliable indicator of your overall health instead of counting on a body fat scale alone.

So, an athlete with a lot of muscle, for example, could have a higher BMI based on their weight and height. Also, the CDC says that women, older adults, and people of Asian descent naturally have higher levels of body fat. All of these factors can limit the reliability of BMI as your sole measurement of health.

While stepping on a scale is perhaps the easiest method of body fat measurement, there are other ways you can determine your body fat percentage. Aside from BMI, you can ask your health provider about the following methods:. The National Heart, Lung and Blood Institute notes that your risk for heart disease and diabetes increases if you are a woman with a waist measurement greater than 35 inches Often used by fitness professionals, calipers are used to literally pinch your skin folds usually around the waist or hips to estimate your body fat.

The accuracy of this method varies. Results may be more or less accurate depending on the expertise of the person taking the measurement. Shop online for body fat calipers. Often used to measure bone mass for osteoporosis diagnoses, DEXA scans are also reliable methods of body fat measurement and can be more reliable than relying on BMI alone.

The scans can be pricey depending on your location and may not be covered by insurance. There are sensors on either side of the device that measure your body fat as you hold the device in front of you.

Shop online for handheld fat measurement devices. This test is based on the buoyancy of your body weight.