OUR VERDICT

The Xiaomi Mi Band 4 delivers fantastic value and features. Upgrades over its predecessor include a color OLED display with significantly improved outdoor viewability and a higher resolution too. The band's battery life is also exceptional, and it has improved tracking, making it an easy fitness gadget to recommend, covering the basics and delivering some flourishes as well - a marked improvement and a worthwhile upgrade.

+FOR

Very cheap

Slimline design

Heart rate monitor

-AGAINST

Only connected GPS

No multitasking apps

Doesn't auto-stop tracking

The Xiaomi Mi Band 3 was good, but the Xiaomi Mi Band 4 is vying for greatness.

For less than the price of two movie tickets, a couple of tubs of popcorn and two supersized sodas, you could be getting active with a color display, heart rate monitor and a connected GPS. The band even packs swim tracking, and unlike its predecessor, its screen is easy to see indoors, and out.

The body of the band is no more imposing, fitting in Mi Band 3 straps, and it's also no less user-friendly, with a simple menu system. 

What the update does bring, however, is a bigger, flat screen for less fiddly swiping, and a slightly larger capacity battery, so the extra color and brightness don't result in worse battery life - impressive, given the 21 days quoted on a single charge. 

Xiaomi Mi Band 4 price and release date 

Available now 

Costs $39.99/£34.99/AU$59

Xiaomi is selling the Mi Band 4 now globally. Specifically, in the US it can be bought on Amazon for $39.99, and in the UK, it's available through Xiaomi's official store for £34.99. If you’re in Australia, it’s available from both Amazon or the official Xiaomi Store for AU$59.

There's also a more expensive version available in China, but the only extra feature it packs is NFC, and that’s loaded up to enable payment services that aren't supported in the US or UK.

Design and display 

Same strap fitting as Mi Band 3 

Larger 0.95-inch display 

Up to 400 nits brightness 

The Xiaomi Mi Band 4's design is clean, simple and looks nothing short of run-of-the-mill until the display is fired up in its full-color glory.

The tracker is light on the wrist at 21g, so, by comparison to a smartwatch like the Amazfit Verge or the Samsung Galaxy Watch Active, we didn't even notice we were wearing it. 

The front of the Mi Band 4's core unit is the touch screen as well as a capacitive button below it. Interaction across these elements is a combination of swipes and taps. Its undercarriage is where the heart rate monitor sits, alongside a pogo pin connector for charging. 

As for the strap, the simple buckle system is secure, comfortable, and is made from thermoplastic polyurethane. Available in black, it might not seem like a party on your wrist, but a range of styles and colors can be picked up if you shop around for old Mi Band 3 straps (they play nicely with the Mi Band 4).

The screen on the Mi Band 4 is bigger than that of the Mi Band 3, measuring 0.95 inches. It's also higher resolution, and interaction is better this time around too, with less missed taps and swipes.

Viewability is also significantly better thanks to the fact brightness climbs up to 400 nits. This means that indoors or out, it's easy to see, and when combined with smart gestures to wake it up with a wrist twist, it's the first Mi Band device to feel like it could be a smartwatch replacement.

You can take the Xiaomi Mi Band 4 swimming or into the shower too as it's also waterproof up to 50 meters, just like the Mi Band 3.

Fitness tracking 

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.

Battery life 

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.

Verdict 

The Xiaomi Mi Band 4 gets right what its predecessor got wrong - outdoor viewability is great, and you can start workouts from your wrist, reducing the band's reliance on your smartphone.

With 5ATM waterproofing, sleep tracking and a connected GPS, it's also got enough smarts to rival plenty of pricier trackers, and even the heart rate monitor did a decent job provided the Mi Band 4 was secured snuggly in place.

Combine all that with a color screen that brings the Band to life, and while we did have gripes with the smartphone app's UI and the band's lack of multitasking, given the band's price, we're still left overwhelmingly impressed.

Who's this for? 

Anyone looking for an affordable fitness tracker that has basic smartwatch functionality without breaking the bank, the Xiaomi Mi Band 4 could be just the ticket.

It's thin, light and comfortable to wear, and even if you never use the smartphone app after setting it up, can still add value to workouts and life as a timepiece, stopwatch, timer and heart rate monitor.

Should you buy it? 

Given the Mi Band 4 represents excellent value for money, unless you need more advanced fitness features or app support, as found on true smartwatches, we can very readily recommend it.