- 5ATM waterproof
- Connected GPS
- Heart rate monitor
Step tracking on the Xiaomi Mi Band 4 tallied nicely with other trackers in day to day use, and is always on.
On the rear of the tracker is a heart rate sensor that sits directly on your skin. By contrast, it isn't always-on, so it won't continuously be recording your heart rate when you're going about your day.
Instead, you need to activate it to get a score through to your wrist and have it recorded in the Mi Fit app on your phone. This can also be done by firing up a workout, which engages constant tracking for the duration of your session and shows you how you’re doing on the band’s display.
You'll find the tracker will record your distance when you're running too, and works in conjunction with your phone's GPS, for a connected GPS experience. For casual runners who don't mind taking their phones with them when out and about, this should be fine, but if you want something a bit more lightweight, you'll want an all-in-one solution that the Mi Band doesn't offer.
The tracker also has modes for cycling and swimming, but we haven't tested it for either of those activities yet. After over a week of showers and a submersion test though, we can attest to its waterproofing.
You can fire up activities from the band itself. By contrast, when we reviewed the Mi Band 3, a phone was required to launch training sessions, and this is a huge win for the latest version. It even congratulates you when you hit milestones like 1KM, which is a nice touch.
This all comes together to make Xiaomi's new tracker a very similar looking bit of kit, but one with significantly more value for casual exercisers and gadget fans alike.
Our main gripe with the tracker is that features like the stopwatch or timer can't be accessed during a workout. The main screen is locked to workout monitoring, and this was particularly frustrating for us during gym workouts. Other than that though, we found very little to grumble about when given the bargain price of the Mi Band 4.
Specs and other features
- Basic watch functionality
- Stopwatch, timer and other tools
- A range of watch faces supported
The Mi Band 4 features a 3-axis accelerometer and a 3-axis gyroscope. This is vital for step-tracking, but also enables the priceless motion-to-wake gesture that gives the band the functionality of a practical wrist watch.
The Band 4 also offers sleep tracking, and thanks to the slim and light weight design we didn't notice we were still wearing the tracker in bed. It measured a bit less deep sleep than the Samsung Galaxy Watch, but overall sleep times were comparable.
Unlike more premium devices, it doesn't provide REM sleep details, like some top-end Fitbit products or a dedicated tracker.
The default display showcases the time nice and clearly. There’s also an activity loop, visually displaying how much exercise you've done today, there’s a battery percentage indicator and the date.
You can also fire a variety of notifications to your wrist, including calls, texts, alarms, reminders and app notifications, and these can be customized through the smartphone app.
App and compatibility
- Android/iOS compatible
- Comprehensive, but unintuitive app
- Easy set-up and interaction with band
The Mi Band 4 features Bluetooth 5, and it works with phones running Android 4.4 and above, or iPhones running iOS 9.0 and above. To get it connected and synced, you just have to download the Mi Fit app to your phone from the App Store of Google Play Store.
App set up is easy, and through your smartphone, you can customize the band, from downloading fun watch faces through to setting alarms and event reminders.
The app also breaks down the data into days, showing your sleeping pattern, step count, heart rate, weight (if you choose to enter it manually) and more. The interface looks pleasant, but the UX is a bit finicky. Buttons aren't always clear, so we didn't always know what to press to access what we were after.
So while the Mi Fit app does cover the basics and do what you need it to, with no detailed breakdown of data to keep you motivated, and unintuitive UX design, our most enjoyed time with the Mi Band 4 was when we were using the device itself.
- 135mAh capacity
- Excellent battery life
- Fiddly charging cradle
The Xiaomi Mi Band 4 sports a 135mAh battery. We used the tracker for just over a week with a couple of training sessions in there, and our battery reading went down by 32%. That tallies up with Xiaomi's claim of 20 days, though your final day-count will depend on your watch face, activity tracking and general usage.
Charging up the Xiaomi Mi Band 4 is pretty fiddly. You have to pop the tracker out of its band and slot it into a proprietary charger, so this won't work with a micro USB or USB-C cable. It does charge quickly, however, plus, you'll only need to charge it up about 18 times a year if Xiaomi's 21-day battery life proves true in the long run.