Xiaomi Mi Smart Band 4 review: It offers a lot for little money


The Xiaomi Mi Smart Band 4 is an affordable health and fitness device that does not empty your pockets and doesn't let you down on hardware specifications. Featuring a color RGB AMOLED screen, a battery that can theoretically last for up to twenty days, water resistance, and an accurate heart rate tracking sensor, all for a low price, you can see why many people are considering purchasing it. If you are too, read this review and find out if it is worth buying and why:

Xiaomi Mi Smart Band 4: Who is it good for?

The Xiaomi Mi Smart Band 4 is an excellent choice for people who want:

  • To track and improve their fitness
  • A fitness band that can track the heart rate accurately
  • To use their fitness bands while swimming
  • A good fitness band with a small price

Pros and cons

There are quite a few things to like about the Xiaomi Mi Smart Band 4:

  • It gathers plenty of useful data about you, during regular activities as well as during workouts
  • Useful heart rate tracking
  • It is water-resistant
  • The AMOLED color display is bright, and its resolution is reasonably high
  • Its battery is enough to keep it going for at least one week
  • The wrist strap is comfortable
  • It can show you notifications when you're getting phone calls, as well as notifications sent by the apps on your smartphone
  • The Find device feature is useful
  • It's very affordable

We also have a few weaknesses to mention:

  • It fails to track your sleep patterns accurately
  • The mobile app could be improved
  • There is no way to see your data in a browser using your Xiaomi Mi account
  • If you change your smartphone, you risk losing all your data, even if you connect to the same account
Product rating 4/5


The Xiaomi Mi Smart Band 4 is an excellent fitness band for users with a low budget. Its main qualities, besides price, are the bright and responsive touch screen, the water resistance, and the accurate heart rate tracking. We believe that this fitness band is a great choice for people who intend to buy their first device of this type, as well as for those who want to spend only a small amount of money. However, if you are seriously committed to fitness and sports in general, you might want to look at more expensive alternatives.

Unboxing the Xiaomi Mi Smart Band 4

The Xiaomi Mi Smart Band 4 comes in a long and rectangular box that looks pretty stylish. On its front, you can see an illustration of the fitness band, a small Mi logo, and the large number 4 that tells you the band's version.

Xiaomi Mi Smart Band 4: The box

If you want more details about your new fitness band, you can find them printed on the back and sides of the box. Inside, you get to see what you've paid for: the Xiaomi Mi Smart Band 4, a proprietary USB charger, the user guide, and the warranty.

Xiaomi Mi Smart Band 4: The contents of the package

The unboxing experience for the Xiaomi Mi Smart Band 4 is straightforward. The package contains everything you need to get started quickly.

Design and hardware specifications

The Xiaomi Mi Smart Band 4 looks just like any other budget fitness band, at least when it is turned off. The device itself, without the wristband, is plain and simple, with a rectangular form. That means that it's easy to stick a screen protector on it, if you are into that sort of thing, although the screen is already protected by 2.5D tempered glass. On the other hand, a curved screen might have looked better and more stylish.

Xiaomi Mi Smart Band 4: What it looks like

The good news is that the screen is excellent compared to the ones on the previous iterations of Xiaomi Mi bands. The Mi Band 4 has a 0.95-inch AMOLED display with a resolution of 120 x 240 pixels and 24-bit RGB color depth. It's also bright, being able to reach up to 400 nits at maximum brightness.

On the back of the device, you can find the heart rate monitoring sensor and the charging contacts. Furthermore, the Xiaomi Mi Smart Band 4 also has a 3-axis accelerometer and gyroscope sensor, and a proximity sensor.

The heart rate sensor and the charging connectors on the Xiaomi Mi Smart Band 4

There are no physical buttons on the band: the screen is touch-sensitive and besides swiping on it, you can also use a capacitive button found at the bottom of the screen. This button is used for waking the band and for going back when navigating through its menus.

The wrist strap is made of thermoplastic polyurethane, which offers it a small amount of elasticity, but also resistance to abrasion. The wristband is 18 mm wide, and its length is adjustable, ranging from 155 to 216 mm maximum. That means that it should be a good fit for anyone, both men and women, regardless of how large or small your wrists are. It is also worth mentioning that the band weighs only 22.1 grams.

The Xiaomi Mi Smart Band 4 out of the wrist strap

One thing that many people want from a fitness band is the ability to work during water sport activities. Fortunately, the Xiaomi Mi Smart Band 4 is waterproof and can withstand up to 5 ATM. That means that you can keep it on your wrist when you're swimming, for instance, and that is a big plus from us.

Regarding the band's connectivity, you should know that it uses Bluetooth version 5.0 and has support for BLE. BLE comes from Bluetooth Low Energy and describes the device's ability to use small amounts of energy to keep the Bluetooth connections turned on. Speaking of which, Xiaomi advertises this fitness band as being capable of lasting up to 20 days and fully charge in less than 2 hours. Its autonomy is provided by a rather small 135 mAh Lithium-Ion Polymer battery. As you can see in the next section of our review, this is possible if you are not using all the features of the band, although its autonomy is impressive even if you do.

The charger of the Xiaomi Mi Smart Band 4

Xiaomi Mi Smart Band 4 has 512 KB of RAM and 16 MB of ROM. The ROM (Read-Only Memory) is more than enough to store the band's firmware, settings, and logs, as well as some customizations, such as display skins.

In terms of operating systems supported, the Xiaomi Mi Smart Band 4 officially works with any smartphone running on Android 4.4 or above, as well as with any iPhone running iOS 9.0 or above.

The Mi Fit app main screen

If you want to read all the official specifications of this product, go to this page: Xiaomi Mi Smart Band 4 Specs.

The Xiaomi Mi Smart Band 4 features some impressive specifications, considering that it's a budget-friendly fitness band. It has heart rate monitoring, a great screen, excellent autonomy, and a reasonable price.

Using the Xiaomi Mi Smart Band 4

The Xiaomi Mi Smart Band 4 is already mounted in the wrist strap, using some edges around the device that fits into place when you press it against the wrist band. Unfortunately, I found it pretty hard to take it out of the wristband and put it back in. The first few times I tried, it felt like I was going to break it. On the other hand, after wearing the Xiaomi Mi Smart Band 4 for a while, I must say that the wrist strap is comfortable, because of its flexibility and also because the material it's made of does not make your wrist sweat. That is an important issue for me, because I'm allergic to quite a few things, and I'm predisposed to unpleasant skin reactions.

How the Xiaomi Mi Smart Band 4 looks when you wear it

Another thing that impressed me quite a lot was the band's battery life. Even though I enabled most of its features, including sleep and continuous heart rate monitoring, the Xiaomi Mi Smart Band 4 managed to keep on going for about 10 days before I had to charge it. That's an outstanding ability considering how small the band's battery is.

Details about the measured heart rate shown in the Mi Fit app

In terms of fitness features, the Xiaomi Mi Smart Band 4 is quite generous. Not only can it count the wearer's steps, traveled distances, and estimated burned calories, but it also comes with six different workout modes. If you're curious about them, know that the band has specialized workout modes for the treadmill, exercise, outdoor running, cycling, walking, and swimming. Unfortunately, except for walking and cycling, I'm not much of a fitness man, and cycling was out of the question during this time, as the weather conditions were pretty bad in my area. However, as far as I've noticed, the Xiaomi Mi Smart Band 4 manages to count steps quite accurately. It does sometimes add some fictional steps that you did not make, but their number is low and doesn't affect the statistics in a meaningful way. It's no more than ten or twenty steps added to the thousand.

Tracking steps with Xiaomi Mi Smart Band 4

One thing that I especially liked about the Xiaomi Mi Smart Band 4 was its media control feature. Wondering what that's about? The band offers you controls for the music you play on your smartphone, and it supports not only music apps such as Spotify but also YouTube. With just a few taps on the band, you can do things like adjusting the volume or skipping to the next song. I believe that is a useful feature when you're out and about running or riding your bicycle.

Xiaomi Mi Smart Band 4 offers music controls

Furthermore, the Xiaomi Mi Smart Band 4 has an impressive screen, which is bright and easy to read even in direct sunlight, which is often the case when you're doing fitness activities outdoors.

The main screen shown by the Xiaomi Mi Smart Band 4

There are also other features that I appreciated having available and which I'm sure many people do too. For instance, I like the fact that the Xiaomi Mi Smart Band 4 can show you notifications and messages that you receive on your smartphone, as well as vibrate when you get a phone call or when an alarm turns on. The display has an excellent resolution, and it's able to show even long notifications, with many characters.

Xiaomi Mi Smart Band 4 lets you receive alerts from the apps on your smartphone

Also, the band's Find device feature is one other thing that was especially useful to me. See, I have a small child, and she often likes to take my smartphone to take photos or play games on it. She often leaves it in the most unexpected places, and I usually have a hard time finding it. The Xiaomi Mi Smart Band 4 made my life easier: using its Find device feature, I could tap a few buttons on it, and my smartphone started screaming, thus making it much easier for me to find it. 🙂

Using the Xiaomi Mi Smart Band 4 to find my smartphone

Finally, I also have to mention the things I don't like about this fitness band. First of all, I would have preferred its screen to be at least slightly curved. That would have made it look a bit stylish. As it is, it looks just common, although that's to be expected from a budget device.

The Xiaomi Mi Smart Band 4 doesn't impress with its looks

Secondly, sleep tracking is not accurate. At least for me, the Xiaomi Mi Smart Band 4 did not manage to track my sleep patterns at all, so I had to edit its recordings each day manually. On almost every night, with few exceptions, I go to bed and watch Netflix or read. During those times, I don't move a lot. I would have expected the band to make assumptions based not only on my movement patterns, but also based on my heart rate (and other information that it gathers), and see that I was not sleeping. On most nights, I fall asleep around 2 or 3 AM. Xiaomi Mi Smart Band 4 thinks I've been sleeping since 11 PM, and its statistics are a long way from the truth. That can be adjusted from the Mi Fit app if you change the habits settings, but that is useful only if you have regular habits. For someone like me, who has an erratic lifestyle, with various sleeping and waking times, the Xiaomi Mi Smart Band 4 doesn't deliver accurate sleep tracking.

Sleep tracking with the Xiaomi Mi Smart Band 4 is not accurate

There are also a few things that could be better about the Mi Fit app and the software environment. The app itself looks nice and offers all the basics you need. However, finding your way through its menus is not intuitive, and you can't use it to change the band's language to be different from your smartphone's language. Unfortunately, that's a negative for me, as many characters from my native language, Romanian, are not displayed correctly on it if my smartphone is set to English. I would have liked to be able to keep my smartphone on English, while the band was set to Romanian.

Xiaomi Mi Smart Band 4 incorrectly showing characters

Also, the information and the statistics from the band are only available in the Mi Fit app. Thus, you can't see them in a web browser, for example, or export them in any way. Furthermore, although you must create a user account with Xiaomi, connecting to it is a hit and miss experience if you change your smartphone. I, for instance, used an Android smartphone (ASUS ZenFone Max Pro M2) with it, and all was well. When I switched to using the Xiaomi Mi Smart Band 4 with another phone, an iPhone SE, I connected the Mi Fit app using the same account. The ugly surprise I had was that all my data was lost from my account, including workouts, sleep, and heart rate data recorded before when I was using the band with the Android smartphone. That's a bad experience, especially if you encounter it after months or years of using Xiaomi's services.

Using the Xiaomi Mi Smart Band 4 is a good experience, but it has its flaws. Its hardware is excellent, it has a good display and battery, and the heart rate tracking is accurate. Considering its affordable price, I'd say that it is a great fitness device for budget-conscious people. However, if you want a fitness band that's more stylish, more accurate in terms of sleep tracking, and which gives you the confidence that you don't risk losing your data than you should save some money and analyze other options too.

Would you buy the Xiaomi Mi Smart Band 4?

Now that you have finished reading this review, what is your opinion about the Xiaomi Mi Smart Band 4? Is it a fitness band that you'd buy or which you already bought? What are your reasons for doing so? You can share your thoughts in the comments section below.

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