When you start using a smart bathroom scale, your weight is automatically logged every time you step on. Many of the best scales also measure body fat, and some track bone density and water percentage. One of our Editors' Choice picks, the Withings Smart Body Analyzer (WS-50), also reads your resting heart rate through your feet.

Training

While many people want to track their weight and the number of steps they take in a day to get a better sense of their health, some people are a little more, shall we say, excited, to get on the scale every morning. Athletes and people who train regularly will want a scale that has not only great features, but a lot of other companion apps and tools that can help them on their journey.

Physically fit people who like the Polar brand of runner's watches and fitness trackers will find the Polar Balance pretty dreamy. The scale itself doesn't have any wow factor, but the Flow companion app is superb. It makes specific suggestions each day for what you can do to attain your weight goal, such as eating four ounces less pizza or running an additional 29 minutes. Flow is one of the most intense fitness and health tracking apps, calculating your training intensity day by day, charting your VO2Max and lactic acid threshold, and more. It's not for the casual couch potato. If you're already a Polar user, the scale is a great addition. But if all this talk of VO2Max makes your head spin, you're much better off with a smart Wi-Fi scale that has a simpler user experience.

Wi-Fi vs. Bluetooth

Smart scales are either Bluetooth-enabled, or both Bluetooth- and Wi-Fi-enabled. Wi-Fi scales generally cost more because they require more components to work. They are also much more convenient.

To get your daily weigh-ins off of a Bluetooth scale and into the app where they'll be tracked, you need a Bluetooth device by your side. If you leave your companion smartphone, fitness tracker, or running watch in the other room, you're out of luck until it's within Bluetooth range. (Some scales can save a recorded weight until the next sync, but the cheaper ones do not.) A Wi-Fi-enabled scale doesn't have this problem. It syncs your data as long as it has a decent signal from your Wi-Fi router. In my experience, Wi-Fi syncing is also more reliable, whereas Bluetooth syncing fails from time to time.

Pregnancy Mode

Women who are pregnant or who might become pregnant have unique needs when it comes to tracking their weight. Plus many pregnant women do not want impedance measurements, which are taken by way of mild electrical impulses sent through the feet to estimate body composition (i.e. body fat, bone density, and water percentage). People who have an implanted health device, such as a pacemaker, are often warned not to use impedance scales either.

While a few scales that support impedance measurements have an option to turn them off, only one scale, the QardioBase, has a full pregnancy-tracking mode. When enabled, impedance is shut off, and the scale flashes a happy face every time you step on it, rather than showing your weight in numbers. The companion Qardio mobile app helps new moms slowly work back to their pre-pregnancy weight, if that's their goal.

Price

Having personally tested and rated a number of smart scales, I'm not at all surprised to see the direct correlation between price and rating. The best smart scales cost more. What makes them more expensive is support for Wi-Fi syncing and a lot of time and energy invested in creating a great app experience.

The least expensive scale to make this list, the Health o Meter Nuyu, costs just $49.99; it has the fewest features and the most limitations, but it's still a good place to start. The two top scales cost close to $150 each. Before you invest in any smart scale, it's good to know the sweet spot of the price range is between $99 and $129.

Fitness Underfoot

If you're looking for a new bathroom scale, I highly recommend buying one that's smart. There's real value for individuals, families, and health care providers to be able to track weight accurately and effortlessly over long periods of time. And no matter your needs, you're sure to find a scale that suits them on this list.