Xiaomi's Mi Band line consists of the best budget fitness trackers in the world - making the decision to pick between the Mi Band 3 or Mi Band 4 an ever-difficult one.
Why? Well, we typically only see small changes between each new model. And though the latest Mi Band does branch out slightly more than older siblings, it can still be tough to decipher what the real differences are.
With this guide and table below, we'll explain all the key points of comparison to help you buy the tracker that's right for you. And don't forget to check out the latest on the Xiaomi Mi Band 5.
|Xiaomi Mi Band 4||Xiaomi Mi Band 3|
|Contactless payments||Only in China||Only in China|
|Water resistance rating||5ATM (up to 50 metres) and swim tracking||5ATM (up to 50 metres)|
|Screen||0.95-inch, 120 x 240 AMOLED||0.79-inch, 128 x 80 OLED|
|GPS||Connected GPS (uses phone GPS)||No GPS|
|Heart rate monitor||PPG optical sensor||PPG optical sensor|
|Battery life||20 days||20 days|
|Compatibility||Android 4.4, iOS 9.0 or above||Android 4.4, iOS 9.0 or above|
Xiaomi Mi Band 4 or Xiaomi Mi Band 3: Which fitness tracker is best?
Below are the most notable differences between the Mi Band 3 and Mi Band 4, though the pair are, as described throughout, very similar trackers.
In our view, the Mi Band 4 is undoubtedly the better fitness tracker of the two, with its colour screen, bigger display, swim tracking and 20-day battery life making it our go-to recommendation for those who want to track their fitness on a budget.
And though you do pay around Â£10 more than the Mi Band 3 for the privilege of those added features, the price is still too low to make much of a difference. Even if you don't think the better display is worth the extra outlay, it's hard not to just take the upgrade for the sake of it.
Whichever way you decide to go, these are two solid budget trackers that are able to match much of, if not all, the same functionality of a rival Fitbit or Samsung.
What's next: Xiaomi Mi Band 5 â what we know so far
Xiaomi Mi Band 4 or Xiaomi Mi Band 3: What are the differences?
We've detailed the full specs and our experience with each fitness tracker in our complete reviews, but, here, we'll compare the two Xiaomi devices in the most important areas.
Below are the six biggest points of comparisons between the Xiaomi Mi Band 3 and Mi Band 4.
1. An all-new color display
The most obvious and considerable upgrade present in the Mi Band 4 is the new display, which now shows colors for the first time.
Every other generation of the Mi Band has been monochrome, which, though better for battery life in years past, was far from enjoyable to read stats from. The move to a full-colour display is a huge advantage the Mi Band 4 has over the Mi Band 3.
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It's not just the colour of the display that's different, either, with the newer Mi Band 4 bringing a 0.95-inch AMOLED screen with a 120 x 240 resolution.
That's up slightly from the 0.78-inch OLED display of the Mi Band 3, which featured a lower 80 x 128 pixel resolution. So, not only is the screen better to look at on the new generation, users also have more room to read and navigate from.
2. Slight design tweaks
The physical design, aside from the display, is fairly similar. That means, too, that both devices are roughly the same weight â the Mi Band 3 clocks in at 20g, while the Mi Band 4 is a slightly heavier 22g.
Naturally, you shouldn't be able to notice any difference that small, and both are exceptionally light trackers on the wrist â perfect for continuous wear and activity tracking.
Both are waterproof up to 50 metres, and control is still achieved through the capacitive touch button on the bottom of the display and the touchscreen.
Owners of the Mi Band 3 looking to upgrade can also be safe in the knowledge that bands can be swapped over to the new generation.
3. More accurate sensors for activity tracking
Basic tracking is present in Mi Band devices, which covers off the likes of steps, calorie burn and sleep.
Exercises, such as running and cycling, are also automatically tracked â with this all aided by the heart rate monitor on the underside of both bands. Neither band includes GPS for location tracking, but the new Mi Band 4 does have the capability to latch onto your phone's GPS to map outdoor activity routes.
A key difference between the two is the Mi Band 4's new six-axis sensor, allowing for more accurate, automatic swim tracking. It means the newer tracker is able to track specific strokes (backstroke, butterfly, freestyle and medley) in the pool.
Essential reading: Best waterproof fitness trackers 2019
And, as you might expect, both feature Bluetooth support, meaning they can pick up notifications from your smartphone. You won't be able to reply, and they're quite hard to read from the small touchscreen (though better on the Mi Band 4), but some users will find this a handy second screen to view.
4. A bigger battery to maintain the same impressive life
How much life you can get out of each tracker will always depend on your usage, though the Mi Band 4 does build in a bigger battery than its predecessor.
The fourth generation tracker comes with a 135mAh battery, which is up from the 110mAh packed inside the Mi Band 3.
However, what does this actually mean when both trackers are in use? Well, in our testing, we found that the Mi Band 4 was able to offer a 20-day battery life â despite having to also cater for a colour touchscreen. Even when we pushed it to 2-3 intensive workouts a week with music playback, heart rate and notifications turned on, it still lasted around 14 days.
It's a very similar picture on the older Mi Band 3 â you're unlikely to get the full 20-day claim unless you strip back some of the features (such as heart rate monitoring and notifications), but you're still getting well above the current average for fitness trackers.
So, in short, Xiaomi has managed to maintain the battery life standards of the Mi Band 3 in the more feature-packed tracker simply by upping the size of the pack slightly and, likely, improving the efficiency of battery consumption.
5. Still an ultra-low price tag
The Mi Band range has stayed consistently low in price throughout the four generations, though there is a slight difference between these two models.
In Xiaomi's home territory, the Mi Band 4 price has been set at CNY 169, which has been essentially mimicked with a Â£34.99 tag from places like Amazon.
In comparison, the Mi Band 3 launched with a price of around Â£25 and has yet to drop from there. All in all, the margin between the two is still small â and both qualify well and truly as budget fitness trackers.