Shopping for a bathroom scale isn’t as straightforward as it once was. You can ?? ??? ?? & ?? ?? ??? ??spend less than $20 or shell out well over $100; have your pick between WiFi and Bluetooth connectivity; keep the focus on body weight or also track your fat, muscle, bone, and water mass; and interact as much or as little with a companion app as you want.
Here are some of the major ways that three of the most popular at-home smart scales (Fitbit Aria Air, Withings Body+, and Garmin Index S2) compare — and which one might be right for you:
Price
The first big differentiating factor is price point. The Aria Airis the cheapest of the bunch, at $49.95. The Body+falls right in the middle, running $99.95. And the Index S2costs the most: $149.99. Keep those numbers in mind as you learn more about each scale — and don’t assume that the cheapest option is always the simplest, or the priciest one the most sophisticated.
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Physical Aspects
Physically, the Aria Air, Body+, and Index S2 are more similar than dissimilar. They’re all about one inch thick, available in two colors (black and white), and boxy with rounded corners and a display in the top center. Size-wise, the Aria Air is slightly smaller than the other two, measuring 11.8 x 11.8 inches. (The Index S2 is 12.6 x 12.2 inches and the Body+ is 12.8 x 12.8 inches.) All three scales have a maximum weight limit between 398 to 400 pounds, and three units of measurement (pounds, kilograms, and stones).
The Index S2 stands out in one aspect: its multicolored display. While probably not a deal-maker, I’ll admit that it does make for nice stats viewing.
Bluetooth vs. WiFi
It may not seem to matter whether a scale connects to your phone via Bluetooth or WiFi. But that difference actually changes the weight tracking experience quite a lot.
Bluetooth-reliant scales — like the Aria Air — sync straight to your phone or fitness tracker. The caveat is that your device has to be nearby while you’re on the scale in order for the measurement to log.
WiFi-equipped scales — such as the Body+ and Index S2 — sync to your device through the internet. That means that your phone can be anywhere, and your data will automatically get recorded. WiFi scales tend to be more expensive, but also more convenient.
Scope of Measurements
When it comes to the amount of information a scale offers, more is appealing, but not always better. In addition to the accuracy limitations of at-home scales (more on that below), too much output can be overwhelming for some users. Others are here for all the data, even knowing that it’s not 100 percent accurate.
On the minimal end of the spectrum sits the Aria Air, which measures just weight and BMI. On top of those, both the Index S2 and Body+ offer the following body composition metrics: fat mass, muscle mass, bone mass, and water mass.
Accuracy of Measurements
In the accuracy department, the Body+ reigns supreme. Whether it actually is “the most accurate smart scale on the market,” as Withings advertises, is impossible for me to say. But it must be somewhere up there, since that claim is based on an independent lab’s weight performance test on similarly-priced scales.
The Body+ has another unique advantage over the other two scales: its patented position aid technology. The accuracy-boosting system helps you evenly distribute your weight on the scale using a system of arrows on the display, and only locks in a number when you’re properly positioned.
The Aria Air and Index S2 offer less information about the technology behind or accuracy of their scales, but it’s fair to assume that they’re relatively accurate on weight, but less so on BMI and body composition metrics.
Companion Apps
Each of the three scales has a companion app, which houses your weight-related metrics.
The Fitbit app(companion to the Aria Air) is designed as a one-stop fitness and health tracking shop, with weight being just one of many components (including exercise, sleep, heart rate, hydration, and nutrition) to focus on. The app, which is simple and colorful, basically serves as a record book for your daily weigh-ins (with BMI). By clicking on the scale icon on your landing page, you can view your data in a table or 30-day graph format.
In the fitness-focused Garmin Connect app(companion to the Index S2), weight feels secondary to workouts. You have to actively search for your weight stats by clicking the “More” tab in the bottom right corner, followed by Health Stats, and finally Weight. Once you’re in, you can then see each of the six metrics the scale tracks (weight, BMI, body fat percentage, skeletal muscle mass, bone mass, and body water percentage) in one-day, seven-day, four-week, and one-year graphs, with corresponding tables below.
The Withings Health Mate app(companion to the Body+) offers the most streamlined weight tracking experience of the three apps. There’s very little navigating required to see all of your body weight and body composition stats, which are presented in neat-looking graphs (weekly, monthly, quarter, and yearly) that you can drag your finger across to pinpoint individual entries. The emphasis in Heath Mate is on weight trend rather than single-day snapshots — which seems like a healthy approach.
Modes
User-specific modes is another area in which the Body+ shines. The scale features dedicated modes for pregnant women, babies, and athletesthat offer personalized insights tailored to each lifestyle or life stage. In pregnancy mode, you get obstetrician-reviewed wellness advice and personalized weight tracking. Baby mode allows you to easily weigh (in your arms) and keep track of your little one’s weight. And athlete mode, which is meant for individuals who work out at least eight hours a week and have a resting heart rate below 60 beats per minute, uses a slightly different algorithm that theoretically yields a more accurate body composition analysis.
Neither the Aria Air nor Index S2 offer such modes (although the predecessor to the Index S2 did have an athlete mode.)
Multiple Users
All three scales allow multiple users to track their weight, as long as they’ve downloaded the companion app, set up an account, and added the scale to their collection of devices. While the Aria Air and Body+ both max out at eight users, the Index S2 accommodates 16. Since these scales are intended for at-home use, most people will not take advantage of that capacity. But for very large families or teams, that might be a big tick in the Index S2’s pro column.
Decision Time
In this three-scale battle, the Withings Body+ scale is the clear champion. Smack in the middle, price-wise, it either rivals or outclasses both the Fitbit Aria Air and the Garmin Index S2 in every important category: It’s WiFi equipped, it measures body weight as well as body composition, its accuracy has been tested and proven in a lab, its companion app is intuitive and uncluttered, and it offers three user-specific modes.
The only scenario in which it would make more sense to get one of the other two scales is if you’re already plugged into the Fitbit (Aria Air) or Garmin (Index S2) ecosystem, and could just tack weight onto the data you’re already collecting in an app you’re familiar with.
Opens in a new window Credit: Withings Withings Body+ 
Opens in a new window Credit: Fitbit Fitbit Aria Air 
Opens in a new window Credit: Garmin Garmin Index S2