Review Samsung Galaxy M31: huge intermediate and with a lot of battery [análise/vídeo]

Launched on the Indian market earlier this year, the Galaxy M31 is the new Samsung intermediary that only arrived in Brazil in July, with a very aggressive proposal and robust technical file. Let’s start with the main one: the device has a battery 6,000 mAh (No, you did not read it wrong). Complete the specifications: a 6.4-inch Super AMOLED screen and four cameras, the main one being 64 MP.

It can be considered that the Galaxy M31 is the “top of the line” of the Galaxy M family. On the other hand, with these specifications, it is positioned between the Galaxy A51 and the A71. In Brazil, it has a suggested price of R $ 2 thousand and, considering that this value may fall in the coming months, the new M-line device may be difficult for the competition.

Anyway, is it worth having the Galaxy M31? Is the battery all that? And the cameras? I have used the device in the past few days and will answer these and other questions in the next few paragraphs.

Review of the Samsung Galaxy M31 on video


The Galaxy M31 follows a similar design to other 2020 smartphones from Samsung. However, most likely to make it cheaper, the South Korean opted for a simpler finish, with plastic on the back and sides. Not that this is a problem.

With regard to colors, the smartphone is available in three options: black, red (almost wine) and blue. To Tecnoblog, Samsung shipped the black M31 – which seems to further enhance the simpler finish. It also accumulates a lot of fingerprints, so I recommend using a cape. Ah, unfortunately, Samsung does not ship the accessory in the box.

Unlike the Galaxy M30, the layout of the lenses here on the M31 follows the “domino” format, which I like very much. The fingerprint reader, on the other hand, could be slightly further away from the cameras, its position does not favor much when unlocking. There was a lack of care here.

Other than that, I had no trouble unlocking the device, the feature responded quickly most of the time. To complete the security system, it is possible to use facial recognition technology, which did better in the test, considering that the position of the button for the digital one is not the best.

Bottom of the Galaxy M31

The volume and unlock buttons are on the right side, while on the left is the tray for you to insert the Nano-SIM and the memory card. And since I mentioned them, no hybrid drawer, it is possible to use two chips and a microSD simultaneously. USB-C and headphone jacks are on the bottom of the device. Speaker and microphone for connection are also there.

The Galaxy M31 is heavier: it’s 191 grams, which is understandable, after all, this phone received a super battery.

Screen and sound

The Galaxy M31 has a 6.4-inch Super AMOLED panel, Full HD + resolution (2340 x 1080 pixels) and 19.5: 9 aspect ratio. The screen is only interrupted by a minimalist droplet notch (Infinity-U), which does not interfere when it comes to consuming content from Netflix or YouTube.

Galaxy M31 minimalist notch

As for quality, Samsung continues to stand out. And thanks to AMOLED, the Galaxy M31 offers great viewing angles, colors are intense and blacks are deep. Details of photographs, games and films can be seen without much difficulty, which made me realize that the strength of this device is not only battery.

Galaxy M31 screen displaying a red image

To help immerse the screen, the edges of the Galaxy M31 have become thinner, but it does not reach the level of frontal utilization of the A51 or A71. But, calm down, that doesn’t mean you won’t have a good immersion when watching movies on that screen, okay? The same goes for games.

The Galaxy M31 has a loudspeaker at the bottom that is quite loud, making it possible to listen to music and podcasts without difficulty in large environments. With the volume at maximum, I didn’t notice distortions, but I felt a slight loss of bass.

Galaxy M31 screen (showing a video with flowers)

Dolby Atmos is here and can be activated by plugging in a headset. It generates a 3D sound experience, but the impression I had is that, when I activated it, there was only an “increase” in volume. I still believe that the DTS: X 3D Surround present in LG smartphones stands out.


The Samsung Galaxy M31 has been running Android 10 and the interface is One UI Core 2.0 and not One UI 2.0 – this means that some features were left out, compared to other newer smartphones from Samsung. Secure Folder and Samsung Pay are not supported here; the Samsung Galaxy M31 does not have NFC (Near Field Communication).

Galaxy M31 running Android 10

Although it is simpler, the interface of the M31 pleased me a lot. At times, it felt like I was working on a high-end device. It is clear that the processor and the AMOLED screen contribute to generate this “sensation”. If I had to change something, maybe the notification bar could be a little cleaner: too many features can hinder and confuse the user.

Galaxy M31 notification bar

The device already comes with some pre-installed apps: Google’s app package, TikTok, Kingdom Disney, candy Crush Saga and Microsoft apps (Office, OneDrive, LinkedIn and Outlook). The South Korean also has its own apps, they are here: Samsung Max, Smart Tutor, Smart Switch, Samsung Members and the own browser (which I really like).

Commands already known on other Samsung smartphones are present on the M31: double tap to activate the screen; gesture reading, which allows you to take a screen capture with the palm of your hand; and when you press the lock button twice, you launch the camera app. And speaking of the camera …


The four lenses of the Samsung Galaxy M31

Since the M31 is the most expensive model in the M line today (in Brazil), there is nothing more fair than bringing a complete photographic set. Yeah, Samsung did it. Starting from the main, it has 64 megapixels and an aperture of f / 1.8 – as you can see in the product images, the company is highlighting this “absurd” number on the back, after all, this helps in marketing. But is it good?

Yes. In environments with good lighting, it can deliver beautiful images with an ok level of detail and consistent sharpness. But there are caveats: post-processing abuses (a lot) saturation. I see this as a problem, because you will have to reduce the saturation in a photo editing application, so as not to spoil your image when adding a filter.

Photo of a Russian doll taken with the Galaxy M31

Office items

Night landscape photo

In dark environments, when activating the night mode, the Galaxy M31 until it gets an ok result. It works to remove noise and leaves images with a “paint effect”.

For portraits, there is a depth sensor of 5 megapixels (f / 2.2), generating Dynamic Focus, which focuses on the object / person in the foreground and blurs the background. I got great portraits with this camera and the focus until it worked well, the exception, as always, is for hair.

Ultrawide has 8 megapixels, it could be 12 megapixels, just like the A51 and A71, or 16 megapixels would be excellent. It has an aperture of f / 2.2 and a field of view of 123 degrees. Despite the excess saturation (again), this lens allowed me to play a lot.

Photo of a condominium


Photo of an environment with stairs


Photo of a yellow building with the sky is blue


The Galaxy M31 also features a 5 megapixel (f / 2.4) macro lens and not 2 MP, as we found on other devices on the market. To make the records, the object needs to be at a distance of 3 to 5 cm. About the quality, until I got good images with it, but not indoors. This is a camera that will deliver a better result in outdoor areas with good lighting.

Photo of a yellow flower with the macro lens



For selfies, the front camera has 32 megapixels (f / 2.0) and delivers images with balanced saturation, but post-processing exaggerates a little when trying to make adjustments to the face, giving the impression that the person has done makeup before take a picture.


In short, I liked the photo set of the Galaxy M31 and it has the potential to please even the most demanding consumers in this regard. Excessive saturation made me a little uncomfortable, lacking balance, but nothing that a photo editing app cannot solve.

Hardware and battery

Internally, the Samsung Galaxy M31 does not disappoint. The South Korean chose its own 2.3 GHz Exynos 9611 octa-core processor – the same as the Galaxy A51. It is an intermediate chip with great performance, but it is not entirely dedicated for those who enjoy heavy games.

This means that the device will not run smoothly Asphalt 9 or Call of Duty? No, he will be able to execute, but there may be little gagging here and there.

The M31 still has 6 GB of RAM, which is great for this device. The internal storage is 128 GB, and can expand up to 1 TB through a microSD.

Galaxy M31 apps

During testing, the Galaxy M31 did not crash at any time. The smartphone responds fast, heavy applications open quickly and run smoothly. When playing Asphalt 9 with the medium levels, the performance was great, unlike when I put the graphics at maximum: then it choked a little.

Battery: this is the highlight of the Galaxy M31. And Samsung did not have to remove parts to introduce a 6,000 mAh super battery. It has a headphone jack, all the buttons are here and even had space to put four cameras. We are talking about greater capacity on a company smartphone.

Galaxy M31 battery percentage

Although Samsung is somewhat afraid to say that the battery can last for two days, you will be able to leave this device out of the socket for more than 24 hours.

Even with the brightness at maximum, the smartphone achieved great results: 3 hours of Netflix made the battery go from 100% and reach 86%; another 2 hours of YouTube dropped the percentage to 79%, 1 hour of social media and: 72% remaining. Spotify on the speaker for 1h20 caused that number to drop to 69%. I finished the battery evaluation with 15 minutes of Asphalt 9. Result: there is still 65% left.

To give you an idea of ​​consumption, I started on Netflix at 9am and ended the use at around 5pm (with 65% left). Detail: the smartphone was connected to Wi-Fi throughout the test period. This means that, depending on the use, it is possible to have a battery for two days and with time off. Grade 10!

To power the battery and reach 100%, you will need 2 hours and 40 minutes, this with a 15 watt power supply, which comes in the box. Fully discharged, I reached 50% in 1h12; then another 43 minutes to reach 80%. Could be better.

Is Samsung Galaxy M31 worth it?

Samsung did a great job here and I can say that the Galaxy M31 is an intermediary that has everything to please the consumer who is demanding and also those who don’t care so much about specifications, and just want the basics. Still, it could bring more: NFC and more complete software were missing.

In other countries, there is the option of 64 GB of storage, which could be attractive to those on a limited budget here in Brazil.

Samsung Galaxy M31 with the box

Even with the cons, the Galaxy M31 still stands out for its Super AMOLED screen, excellent battery and four cameras. Maintaining the standard headphone jack, option to unlock the device by digital and facial recognition are features that still support my high score for this smartphone.

The launch price of R $ 2,000 divides opinions, of course. Fortunately, it is possible to find it for around R $ 1,800 in some stores. This also means that most likely the M31 will be priced at R $ 1,500 in a few months, which is very positive. Important to emphasize: it is only sold in online retail, which also explains the most attractive price.

Its competitor is the Xiaomi Redmi Note 9S and you can still include in this ring the newly launched Motorola One Fusion and even the Galaxy A71, which is a little more expensive, but the difference is not so absurd.

If so? Valley!

Samsung Galaxy M31 – specs

  • Screen: 6.4 inch Super AMOLED with Full HD + resolution and Infinity-U notch
  • Processor: Samsung Exynos 9611 octa-core up to 2.3 GHz
  • RAM: 6 GB
  • Internal storage: 128 GB + microSD up to 1 TB
  • Rear cameras:
    • Main: 64 megapixels
    • Ultrawide: 8 megapixels with 123 degree field of view
    • Macro: 5 megapixels
    • Depth: 5 megapixels
  • Frontal camera: 32 megapixels
  • Drums: 6,000 mAh with 15 watt fast charge
  • Colors: blue, black and red
  • Others: rear fingerprint reader, facial recognition, Dolby Atmos

Samsung Galaxy M31


  • Super AMOLED screen
  • Battery for two days (or three, who knows)
  • Android 10 wheel
  • Firm performance and 6 GB of RAM


  • There is a certain abuse in the post-processing of the images
  • Fingerprint reader position can get in the way
  • Missing NFC
  • Missing Folder Safe and more complete software

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