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Samsung Galaxy A21s vs A31: Side-by-side

They may be closely matched in terms of model numbers, but there are reasons to weigh up the respective perks of the Samsung Galaxy A21s and A31.

Samsung A21s
Samsung Galaxy A21s
4 out of 5 stars
  • pro
    Lots of phone for the money
  • pro
    Solid battery life
Samsung A31
3.5 out of 5 stars
  • pro
    Super AMOLED screen
  • pro
    Superior cameras
Nathan Lawrence
Jul 02, 2020
Icon Time To Read5 min read

A21s vs A31 summary

The A21s and A31 are even matched in most regards, leaving us wondering why you'd pay extra for the A31. We lean towards the A21s as a phone that can do it all, and save you $100 in the process.

Postpaid plans are a great way to get everything you need for monthly mobile phone use: calls, data and, of course, the option to pay off a new handset, too.

But while top-end handsets like the Samsung Galaxy S20 cost close to $2,000RRP, cheaper Galaxy handsets are a viable choice for buying a handset outright so you can tap into the ongoing savings of a Prepaid or SIM Only mobile plan.

In the case of the Samsung Galaxy A21s and Samsung Galaxy A31 handsets, the battle continues where it left off last generation. The popular Samsung Galaxy A20 was the right place for a great phone, while the more expensive Samsung Galaxy A30 proved to be less loved by users.

Based on the core Samsung specs, let’s take a look at which of their successors comes out on top.

A21s vs A31: Price

The recommended retail prices (RRPs) for the A21s and A31 represents a price jump for both when compared to their predecessors. The A20 launched at a budget-friendly RRP of $279, while the A30 wasn’t a whole lot more at $379.

That A30 $379 launch price is what you’ll pay for an A21s, with the A31’s price proving to be even steeper than its predecessor at $499RRP, pushing the price gap up to $120.

Of course, the street price for mid-tier smartphones varies quite a bit from the RRP. Not only are both the A21s and A30 cheaper now, but they are also closer in price to one another.

Samsung Galaxy A21s vs A31 price in Australia
Samsung A21s
Samsung A31
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Samsung Galaxy A21s vs Samsung Galaxy A31 specs

On the surface, as the naming conventions may suggest, the A21s is a cheaper version of the Samsung Galaxy A line, compared to the more expensive A31. Here’s a full breakdown of their respective specs:

Samsung Galaxy A21s vs Samsung Galaxy A31 specs
Samsung Galaxy A21s
Samsung Galaxy A31





6.5-inch Infinity-O Display, PLS TFT LCD

6.4-inch Infinity-U Display, Super AMOLED


720x1600 (HD+)

1080x2400 (FHD+)


Quad Camera System

Multi Quad Camera

Battery life

5,000mAh, 15W fast charging

5,000mAh, 15W fast charging

CPU speed

2GHz Octa-Core

2GHz, 1.7GHz Octa-Core




Internal storage



External memory support

Up to 512GB MicroSD

Up to 512GB MicroSD




When we go down this list of specs, there isn't much that really jumps out as major pluses or minuses. The differences in the screens may seem pronounced, but you're unlikely to be disappointed with the LCD panel in the A21s. Especially given that the lower resolution panel definitely contributes to its superior battery life.

Benchmarking results we've seen suggest that the A31 handles some tasks faster, but overall, we're talking about seconds in the time in takes to load an app. That both phones have 4GB of RAM is a good sign.

A21s vs A31: Display

Given the $120 cost gap between the A21s and the A31, the differences between the two expectedly start with the screen. Despite having a larger display at 6.5 inches, the A21s has a noticeably lower screen resolution at 720x1600 (HD+), compared to the 6.4-inch, 1080x2400 (FHD+) screen on the A31.

Additionally, the A21s has an older-tech PLS TFT LCD screen compared to the A30’s Super AMOLED display. The result: everything on screen looks noticeably better on the A30’s Infinity-U Display compared to the A21s’s Infinity-O Display. More pixels spread out over (slightly) smaller screen real estate is easier on the eyes, too.

Infinity-O vs Infinity-U Displays

There’s only a minor difference between Infinity-O, Infinity-U, and Infinity-V displays. While ‘Infinity’ refers to the near elimination of the screen bezel, the ‘O’, ‘U’, and ‘V’ influence the shape and placement of the selfie camera. For Infinity-O, the selfie camera is off to the side in an O shape. For Infinity-U and Infinity-V screens, the selfie camera is at the top centre of the screen, with a U or V shape, respectively.


In basic terms, PLS TFT LCD displays are an older (but more common) smartphone screen technology and tend to be in cheaper-model phones when compared to the newer Super AMOLED screens. TFT screens rely on a backlight, consume more power, and have a shorter lifespan.

Super AMOLED screens use organic materials, are thinner than TFT, and produce better colours.

A21s vs A31: Cameras

Both the A21s and A31 feature a Quad Camera system on the back, and a single selfie camera on the front. For the front-facing selfie camera, the A21s has a 13MP (F2.2) cam, while the A31 boasts a 20MP (F2.2) upgrade.

On the back, both phones boast a 48MP (F2.0) main camera, which can record video in 1920x1080 resolution, with the main difference being that the A21s is capped at 30 frames per second (fps), while the A31 can record at 60fps.

The other similarity is the ultra-wide cameras, which share a 123-degree view and 8MP (F2.2) resolution.

While the f-stops are the same for the other two cameras, the resolutions are better on the A31. The depth camera is 2MP (F2.4) on the A21s but 5MP on the A31, while the macro camera is 2MP (F2.4) on the A21s but 5MP on the A31. Because of this, you should understandably expect better photographic results for front or back-facing photography on the A31.

Samsung Galaxy A21s

A21s vs A31: Performance

In terms of CPU speeds, the A21s and A31 are comparable, both with an Octa-core processor that can reach speeds of up to 2GHz.

As for memory, the A21s has 3GB, which falls short of the A31’s 4GB. For the smartphone gamers out there, the A31 also includes a Game Booster mode to optimise available system memory, as well as battery life and temperature.

A21s vs A31: Capacity

This is one of the biggest differences between the two Samsung Galaxy A models. The A21s only has 32GB of internal storage, which isn’t a whole lot by today’s standards, especially when stacked next to the A30’s comparatively monstrous 128GB of internal storage.

That said, both Samsung Galaxy A handsets offer the option of expandable memory via MicroSD of up to 512GB. Considering 128GB MicroSD cards are purchasable for less than $50 for certain brands these days, the limited capacity concerns of the A21s can be negated with an affordable upgrade.

A21s vs A31: Battery

Both the A21s and A30 boast a healthy-sized 5,000mAh internal battery, neither of which can be removed (as is the standard these days). Similarly, both Samsung Galaxy A handsets feature fast charging via 15W charger, which means you can get up to 50% battery charge in an hour of charging.

There are some key differences to note in usage scenarios, though:

Samsung Galaxy A21s vs Samsung Galaxy A30 battery life
Samsung Galaxy A21s
Samsung Galaxy A31

Internet usage time (LTE)

Up to 23 hours

Up to 20 hours

Internet usage time (WiFi)

Up to 23 hours

Up to 20 hours

Video playback time

Up to 21 hours

Up to 22 hours

Audio playback time

Up to 109 hours

Up to 97 hours

Talk time (4G LTE)

Up to 54

Up to 33

The table shows that, despite having the same battery, the A21s comes out on top for Samsung’s estimated usage scenarios in every category except for video playback, which the A30 edges out with a one-hour improvement. The A21s is up by three hours in LTE and WiFi usage time, 12 hours for audio playback time, and a whopping 21 hours for 4G LTE talk time.

A21s vs A31: Conclusion

For $120 extra, the A31 should deliver a better screen, better photography and marginally better performance, but these improvements are hard to spot when looking at phones in this price category.

There's no obvious difference that justifies spending the extra money; the phones are the same size, have the same huge battery, run the same apps and perform the same tasks. If we were shopping for a new Samsung, we'd choose the A21s.

Now that you know, here are your next steps. best of logo

Thinking of going premium? Find the Galaxy S20 on a plan best of logo

Or if you need a budget SIM, we've rounded up those too.

Nathan Lawrence
Written by
Nathan Lawrence
Nathan Lawrence has been banging out passionate tech and gaming words for more than 11 years. These days, you can find his work on outlets like IGN, STACK, Fandom, Red Bull and AusGamers. Nathan adores PC gaming and the proof of his first-person-shooter prowess is at the top of a Battlefield V scoreboard.

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