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Mi Band 3i Review – Best Budget Fitness Band?

by Pratik

Mi Band 3i is the latest cheaper alternative to the Mi Band 4 but it is more inspired by the Mi Band 3. So, the question arises “Should you save some money and go for the Mi Band 3i?” or “Is the Mi Band 4’s higher price tag worth it?”. Well, the short answer is “Yes”. The Mi Band 4 is well worth all the money. But, to better explain it, here’s my full review of the Mi Band 3i.

Mi Band 3i vs Mi Band 4: Which one should you get?

We have already compared the Mi Band 3 with the Mi Band 4 and the Mi Band 4 emerged as a winner by a significant margin. Since the Mi Band 3 and Mi Band 3i are so close to each other, I won’t be comparing them. Instead, I would compare it to the Mi Band 4 which has a lot different to offer. To start off, here’s a quick overview of the key difference in specifications.


Products Mi Band 3i Mi Band 4
Display 0.78-inch monochrome OLED touch screen
0.95-inch AMOLED colored touch screen
Display Resolution 128×80
Display Brightness 300 nits
400 nits (adjustable brightness)
Body material
Wrist Strap material
Thermoplastic polyurethane
Button Type
Force-touch resistive button
Force-touch resistive button
Battery capacity
110 mAh
135 mAh
Standby time
20 days
20 days
Charging time
About 2 hours
About 2 hours
Bluetooth Version
4.2 5.0
20 gms (Approx.)
22.1 gms
3-axis Accelerometer
3-axis accelerometer, 3-axis gyroscope,
PPG heart rate sensor,
Capacitive wear monitoring sensor


The Mi Band 3i carries the same 0.78-inch monochrome display which supports up to 48 characters. This means it will support conventional special characters like “@#$%” but won’t support smileys, money symbols, etc. Comparatively, even the Mi Band 4 doesn’t support smileys but can display a greater set of characters. Coming back to the Mi Band 3i display, it isn’t that great outdoors.


The Mi Band 4 just trumps the Mi Band 3i in terms of outdoor sunlight legibility. When it comes down to specs, the Mi Band 3i’s display can get bright up to 300 nits whereas the Mi Band 4 gets 400 nits bright. The brightness can be adjusted on the Mi Band 4 whereas it can’t be adjusted on the Mi Band 3i. Both of them have a force touch-capacitive button that works even when you are wearing gloves. Both of them act as a back button instead of the home button.

The Mi Band 3 charger and the Mi Band 3 straps work with the Mi Band 3i

Lastly, due to the colorful display on the Mi Band 4, the watch supports a wide range of watch faces. You can even create your own watch face and sideload on the Mi Band 4. On the other hand, Mi Band 3i supports 3 watch faces with no option to sideload custom watch faces.

Features & Accuracy

As the Mi Band 3i is a stripped version of the Mi Band 3, it clearly has lesser sensors. The Mi Band 4 has both the 3-axis accelerometer as well as the 3-axis gyroscope whereas the Mi Band 3i only has the 3-axis accelerometer. On paper, the Mi Band 4 should be better at detecting at the angular moment and have better workout detection and accuracy. To test that, I took a stroll around my office measuring the steps and distance manually. Below are the results from both the watches.

Data Source Steps Distance
Manual 429
0.344 m
Mi Band 3i 408
0.330 m
Mi Band 4 444
0.320 m

From the above data, you can see the Mi Band 4 is slightly more accurate when it comes to step tracking. Overall, I found the Mi Band 4 to be more consistent in terms of activity tracking. Additionally, Mi Band 4 also has an inbuilt music controller which helps you control music playback for Spotify, YouTube, etc.

Built-in Activity Launcher

Similar to the Mi Band 3, the Mi Band 3i lets you launch only one activity from the band i.e. treadmill. In order to launch other activities like Running, Walking, Cycling, you would have to head over to the Mi Fit app. Whereas in the Mi Band 4, you can launch a bunch of fitness activities like Outdoor running, Treadmill, Cycling, Walking, Pool swimming, and Free training from within the band. Additionally, the Mi Band 4 also supports automatic swim stroke recognition which comes in handy if you are into swimming.


Battery Life

The Mi Band 4 has a larger 135 mAh battery compared to the Mi Band 3i 110 mAh battery. But, due to the lesser number of sensors and a monochrome display, the battery on the Mi Band 3i clearly outlasts the Mi Band 4. On a continuous usage with sleep heart rate tracking on and 1 fitness activity per day, the Mi Band 4 lasts around 5-7 days on a full charge. With similar usage except the sleep heart rate tracking, the Mi Band 3i lasts around 10-12 days on a single charge.

Third-party Apps

The reason which makes the Mi Fitness bands stand out in every comparison is the third-party app support. It has a huge developer community backing and you have plenty of third-party apps that add an extra layer of utility. For instance, you can do better sleep tracking on the Mi Band using the Sleep as Android app. Gadgetbridge is another open-source offering that lets you use the Mi Bands without the Mi Fit app.

Apart from the watch face apps, you can use most of the third-party apps with both Mi Band 3i and Mi Band 4.

gif explaining remote shutter feature of the mi band 4 selfie camera app

Closing Words

I would recommend going for the Mi Band 4 since it has a lot more to offer. The Mi Band 3i seems a better deal but it’s just an old iteration watch with no heart rate sensor. For more queries or issues regarding the Mi Fitness bands, let me know in the comments below.

Also Read: How to Check Heart Rate on Android and iPhone

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