Samsung Galaxy M31 Review

The Samsung Galaxy M31 is the successor to the Galaxy M30, built around a 6000 mAh battery aimed at users who want long runtime between charges. This review covers the Galaxy M31 across its design and build, its Super AMOLED display, the Exynos 9611 performance, the four-camera system, and battery life.

Design & Build

The Galaxy M31 follows Samsung’s standard design language, with rounded back edges and a front dominated by the display inside a thin bezel. It is a heavier and thicker phone than the M30, mainly because of its cell: the unit weighs 191 grams and measures 8.9 mm at the edge, the space needed for the 6000 mAh battery. The body and frame are plastic. Color options are pink (magenta), blue, and black.

The volume and power buttons sit on the right side, while the left side holds the card drawer. The Galaxy M31 takes two SIM cards plus a microSD card in a dedicated slot, so expanding storage does not cost a second SIM. The bottom edge carries a 3.5 mm headphone jack, a USB-C port, and a single speaker; microphones sit on the lower and upper edges.

The fingerprint sensor is on the back and responds quickly. Face recognition through the front camera is also available; it works reliably in normal light but is affected as light levels drop. The Galaxy M31 is not water resistant, so it is a fit for users who do not require splash or water protection.

Display

The Galaxy M31 has a 6.4-inch Super AMOLED display with a small drop notch for the front camera. It runs at 1080×2340 pixels for a density of 403 ppi, with a 19.5:9 aspect ratio and an 84.1 percent screen-to-body ratio. Color, resolution, and black levels are strong for this segment, as expected from an AMOLED panel at this size. Under harsh direct sunlight the brightness is limited, which is worth noting for outdoor use.

Performance & Software

The Galaxy M31 runs Android 10 with the One UI 2.0 interface. Its processor is the eight-core Exynos 9611, which pairs four Cortex-A73 cores at 2.3 GHz with four Cortex-A53 cores at 1.7 GHz. Graphics are handled by the Mali-G72 MP3. The review unit has 6 GB of RAM and 128 GB of storage.

In gaming, PUBG runs smoothly at high graphics settings. The phone warms up during longer sessions: idle temperature is around 27 degrees, rising to about 39 degrees after 30 minutes of PUBG.

In synthetic tests, the Galaxy M31 records the following scores:

Benchmark	Score
AnTuTu	194,502
Geekbench (single-core)	347
Geekbench (multi-core)	1362

These figures place the Galaxy M31 in the mid-range performance tier.

Camera

The Galaxy M31 has a four-camera array on the back. The main camera is 64 MP with an f/1.8 aperture and a 26 mm wide angle. It does not include optical image stabilization, and its autofocus is listed as phase detection autofocus (PDAF). The second camera is an 8 MP ultra-wide with an f/2.2 aperture.

Both the rear and front cameras record 4K video. The front camera is 32 MP with an f/2.0 aperture and a 26 mm focal length, and it produces good results in daytime shooting. Live Focus mode on the front camera blurs the background behind the subject. Front-camera quality declines as light conditions weaken.

By default the front camera captures at 8 MP; reaching the full 32 MP requires changing the image ratio in the camera settings. The rear main camera works the same way, as full 64 MP capture requires switching the resolution setting first. Both cameras take good daytime photos, while image quality drops in low light. A Night mode is included, though it is not particularly effective.

Battery

The Galaxy M31 carries a 6000 mAh battery, which is its defining feature. With normal use it comfortably lasts more than two days, which makes it well suited to users who watch a lot of video on the phone.

In a 90-minute Full HD video test at full screen brightness over Wi-Fi, the phone lost only 9 percent of its charge, which points to roughly 16.5 hours of video playback; lowering the brightness extends this further. Gaming is similar: 30 minutes of PUBG uses about 8 percent, which works out to roughly 6 hours of continuous play.

Charging uses a 15W adapter, and the large capacity means it is not fast:

Elapsed time	Charge level
30 minutes	22 percent
1 hour	55 percent
Full charge	2 hours 35 minutes

Pros & Cons

• Pros: 6000 mAh battery with more than two days of normal use; Super AMOLED display; four-camera system with a 64 MP main sensor and 4K video; dedicated microSD slot alongside dual SIM; 3.5 mm headphone jack.
• Cons: limited brightness in harsh sunlight; slow charging relative to battery size; no water resistance; weak Night mode; plastic body and frame.

Technical Details

Display	6.4-inch Super AMOLED, 1080×2340, 403 ppi, 19.5:9
Processor	Exynos 9611 (4x Cortex-A73 2.3 GHz + 4x Cortex-A53 1.7 GHz)
Graphics	Mali-G72 MP3
Memory	6 GB RAM, 128 GB storage, microSD expandable
Rear cameras	Four-camera array; 64 MP f/1.8 main, 8 MP f/2.2 ultra-wide
Front camera	32 MP f/2.0
Battery	6000 mAh, 15W charging
Software	Android 10, One UI 2.0
Weight / thickness	191 g, 8.9 mm

Related review: Xiaomi Redmi Note 9S.

Who Is Samsung Galaxy M31 For?

The Galaxy M31 fits users whose first priority is battery life. The 6000 mAh cell delivers more than two days of normal use and long video playback, which suits heavy video watchers and anyone who wants to charge less often. The Super AMOLED display, the four-camera system with 4K video, and the dedicated microSD slot add to its appeal. Users who need fast charging or water resistance will find the M31 less suited to those needs; but for long endurance it is a solid choice for those who value staying unplugged.