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The best smart scales we tested in 2019: Withings, Fitbit, Garmin, Eufy and JaxJox

The best smart scale can tell you about much more than just your weight.

Today's bathroom scales can do so much more than just show you your weight. They can provide you with a more complete picture of your body, tracking your weight over time, helping you with weight loss and measuring how much fat and muscle you have, among other metrics.

A smart bathroom scale can do all of those measurements and more. But with so many smart bathroom models available, it's hard to pick the best smart scale for you. Whether you've got weight-loss goals, fitness goals or you're just interested in your health stats, here I'll break down the top smart bathroom scales on the market to help you choose the best smart scale.

What is a smart scale?

Put simply, a smart scale is one that uses Bluetooth or a Wi-Fi connection to sync all of the metrics it records about you to a health app on your phone such as Apple Health. Many of these bathroom scales have sensors to measure body fat percentage (including BMI and visceral fat), muscle mass, bone mass, heart rate and more measurements and data, in addition to weighing you.

The flaws in measuring body fat with a scale 

All of the scales on this list can measure your body composition, weight and BMI using an electrical current that travels from the scale's sensor through your leg, across your pelvis and down the other leg. It measures how much resistance that current encounters and then uses a mathematical formula to estimate how much fat, muscle and bone makes up your entire weight.

While these features are useful, they aren't always reliable. Consumer Reports tested the accuracy of many scales that measure BMI and body fat percentage and found that most didn't hit the mark compared to a BodyPod -- one of the gold-standard clinical tests for body fat measurements.

Those data inaccuracies can be chalked up to many things, including if you're sick, retaining water, have recently exercised, are menstruating or have consumed alcohol. One of the most influential factors is where you carry your weight -- if your chest and arms are slim, but you have more fat and muscle in your pelvis and legs, it might incorrectly calculate your overall body fat percentage.

Each scale I stepped on gave me a different body fat percentage, but each number was within a 10% range. But for muscle mass percentage measurements, the range was between 33% and 63%. Two of the scales I tested provide a basal metabolic rate (BMR), but there was a whopping 631-calorie difference between the two. That's more than one McDonald's Big Mac or three glazed Krispy Kreme donuts.

All of this is to say, don't get caught up in those metrics. Follow the directions that come with your scale to get the most accurate measurements and data possible, and if you are concerned about your body fat percentage, body composition, health or fitness, talk to your doctor about getting a proper scan.

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James Martin/CNET

Of all the scales I tested, this is my favorite. That's mostly because the Eufy app (iOS and Android) that you use with the scale is very easy to navigate, and the app gives you detailed data and reports of your weight, body fat, water, muscle mass, bone mass, BMI, BMR and more. The app will also flag those measurements as low, normal or high, so you know how your health stats compare to what's considered the standard in health and fitness for your height and age.

Comparing my stats to other scales, Eufy's seemed the most consistent with its data, though my BMR is suspiciously high. One of the best things about the Eufy scale is that it supports up to 16 different users. Simply select the correct user in the Eufy app and all of your data and metrics from the scale will sync to that profile in the mobile app. It also connects with Apple Health and Fitbit.

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James Martin/CNET

Withings' digital bathroom scale comes packed with lots of features that go above and beyond the rest. It provides detailed historical data and metrics on your weight, BMI, body fat, muscle mass, body water, heart rate and bone mass, so you can see how those measurements and your health and fitness change over weeks, months, quarters and years. This bathroom scale also records the weather every day that you hop on the scale, to help you decide what to wear if you step on the scale first thing in the morning.

What sets the Body Cardio apart is that it has modes for pregnant women, babies and athletes, each tailored to specific needs. If you activate pregnancy tracking, it will plot your weight changes over the course of your pregnancy and suggest to turn off the body composition features, which aren't as accurate while you're carrying.

Baby mode allows you to hold your infant and step on the scale to only measure their weight. Athlete mode accounts for professional athletes, bodybuilders and anyone who weighs more because they have a lot of muscle mass and low body fat and BMI.

Two more bonuses: This bathroom scale uses a rechargeable battery (with a battery life of approximately 18 months) -- many scales run on a bunch of AA batteries or AAA batteries -- and it supports up to eight different users.

Runners-up

James Martin/CNET

The Fitbit Aria 2 Wi-Fi scale measures weight, BMI and body fat, but it gave me less data than the rest of the scales. This digital bathroom scale is best for people who currently use a Fitbit wearable and want all of their data -- activity, nutrition, weight, BMI, body fat, sleep -- in one dashboard. The Aria 2 also gets points for being really cute. As you interact with the bathroom scale, you see an animated face that smiles at you and goes to sleep as the device goes into standby mode.

This device also includes a lean mode, for professional athletes or bodybuilders whose physiques are different from the average person. Plus, up to eight people can use the Aria 2 and each of their metrics and data are saved to their user profiles in the Fitbit app (Android and iOS).

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James Martin/CNET

Do you already use a Garmin fitness tracker? Then you might want to get a Garmin Index smart scale to go with it. Garmin's Connect app (Android and iOS) offers a holistic view of your health, including data and metrics such as your activity level, weight, BMI, body fat percentage and other measurements and data.

The bathroom scale measures weight, BMI, body fat, body water, muscle mass and bone mass, and it offers charts for tracking weight loss and other data over a week, a month and a year. It uses four AA batteries, and battery life is up to nine months.

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James Martin/CNET

While the JaxJox bathroom scale is best used in tandem with JaxJox's smart kettle bell, activity tracker and/or heart rate monitor, it does a good job on its own. Even if you don't own any other JaxJox product, this scale is still worth your attention because its BMR and BMI measurements and data were the most correct out of any of the scales I tested.

It also measures visceral fat, which research now shows is the fat most associated with insulin resistance, high levels of bad cholesterol, and low levels of good cholesterol. This bathroom scale is also cheaper than most of the scales on this list. And you can use the app (Android and iOS) to sync your activity data from Apple Health to your mobile device (iPhone only).

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Originally published earlier this year.