Samsung Galaxy A51 review

GSMArena team, 31 Jan 2020.

6.5-inch Infinity-O Super AMOLED

The Galaxy A51 has a 6.5-inch Super AMOLED display with 1080 by 2400 pixels in a tall-for-a-Samsung 20:9 aspect ratio. It's an Infinity-O panel, meaning it's got a punch hole for the selfie camera, as opposed to a notch of any sort or shape. The A51 and A71 were the first non-flagships in the company's lineup to adopt that approach, with the Lite S10 and Note10 following.

Samsung Galaxy A51 review

Infinity-O or otherwise, it's still a Samsung OLED display and behaves in much the same way we've come to expect from those. We measured a maximum brightness of 636nits when the Adaptive brightness toggle was engaged and 413nits if you take over control of the slider. Minimum brightness was 1.8nits.

Display test 100% brightness
Black,cd/m2 White,cd/m2 Contrast ratio
Samsung Galaxy A51 0 413
Samsung Galaxy A51 (Max Auto) 0 636
Samsung Galaxy A50 0 424
Samsung Galaxy A50 (Max Auto) 0 551
Xiaomi Mi 9T 0 449
Xiaomi Mi 9T (Max Auto) 0 646
Realme X2 0 432
Xiaomi Redmi Note 8T 0.331 450 1360:1
Xiaomi Redmi Note 8T (Max Auto) 0.453 600 1325:1
Xiaomi Redmi K30 0.399 550 1378:1
Xiaomi Redmi K30 (Max Auto) 0.527 714 1355:1
Xiaomi Redmi Note 8 Pro 0.347 460 1326:1
Xiaomi Redmi Note 8 Pro (Max Auto) 0.486 640 1317:1
Nokia 7.2 0.371 498 1342:1
Nokia 7.2 (Max Auto) 0.421 585 1390:1
Honor 9X 0.361 464 1285:1
Motorola Moto G8 Plus 0.317 477 1505:1
Motorola Moto G8 Plus (Max Auto) 0.395 581 1471:1

Color rendition is handled familiarly - the Natural/Vivid approach Samsung introduced recently. Natural aims to reproduce sRGB content truthfully, and we measured a very good average deltaE of 1.8, though 100% Green was particularly off with a deviation of 5.4.

The Vivid mode offers a 5-position cool-to-warm slider, and we were particularly impressed with the spot-on whites and grays at the warmest setting, which yielded an overall average deltaE of 2.7 when examining color swatches against their DCI-P3 targets. The mid-point on the slider will get you slightly worse average deltaE of 3.3 and not as accurate whites - moderately shifted towards blue to the tune of a deltaE of 4.

Samsung Galaxy A51 battery life

The Galaxy A51 has a 4,000mAh battery inside, same capacity as the model it replaces and pretty much par for the course in the segment. Despite using the same chipset, the A51 does come with a slightly larger display and a different OS, so we expected at least some difference in the battery life, and indeed that's what we got.

We clocked 13 and a half hours on the web over Wi-Fi, a full hour more than what the A50 managed. Then again, we're witnessing an hour and a half drop in video playback to 14:22h - still a respectable number. The 22-hour call time isn't spectacular, but it'll do. In the end, the Galaxy A51's overall Endurance rating adds up to 86 hours.

Samsung Galaxy A51

Our battery tests were automated thanks to SmartViser, using its viSer App. The endurance rating above denotes how long a single battery charge will last you if you use the Samsung Galaxy A51 for an hour each of telephony, web browsing, and video playback daily. We've established this usage pattern so that our battery results are comparable across devices in the most common day-to-day tasks. The battery testing procedure is described in detail in case you're interested in the nitty-gritty. You can check out our complete battery test table, where you can see how all of the smartphones we've tested will compare under your own typical use.

Using the supplied adapter, the Galaxy A51 charges from flat to full in 2:14h, which won't win it any contests, but is fairly decent. At the 30-minute mark, we were looking at 35%, and that too isn't praiseworthy.

Speaker test (new)

Use the Playback controls to listen to the phone sample recordings (best use headphones). We measure the average loudness of the speakers in LUFS. A lower absolute value means a louder sound. A look at the frequency response chart will tell you how far off the ideal "0db" flat line is the reproduction of the bass, treble, and mid frequencies. You can add more phones to compare how they differ. The scores and ratings are not comparable with our older loudspeaker test. Learn more about how we test here.

Audio quality

Next up - testing the quality of the output through the audio jack. The Samsung Galaxy A51 put in a spirited performance with an active external amplifier, getting top marks while maintaining downright impressive loudness.

The volume remained high with headphones, and we got a bit of extra distortion and a moderate amount of stereo crosstalk. All things considered, it’s an excellent showing by the mid-ranger, though.

TestFrequency responseNoise levelDynamic rangeTHDIMD + NoiseStereo crosstalk
Samsung Galaxy A51+0.03, -0.05-93.193.10.0240.041-87.3
Samsung Galaxy A51 (headphones)+0.13, -0.19-93.293.20.1310.193-53.8
Samsung Galaxy M30s+0.03, -0.05-93.793.50.00080.0078-93.2
Samsung Galaxy M30s (headphones)+0.17, -0.26-93.092.90.0750.248-54.9
Redmi Note 8+0.02, -0.02-94.094.00.00190.0067-93.3
Redmi Note 8 (headphones)+0.35, -0.26-91.390.90.0150.445-45.4
Motorola Moto G8 Plus+0.02, -0.01-93.293.20.00170.051-94.2
Motorola Moto G8 Plus (headphones)+0.02, -0.01-93.193.00.00350.037-83.8
Realme X2+0.03, -0.06-92.692.60.00200.0080-88.1
Realme X2 (headphones)+0.30, -0.37-87.291.00.00810.356-48.4

Samsung Galaxy A51 frequency response
Samsung Galaxy A51 frequency response

You can learn more about the tested parameters and the whole testing process here.

Reader comments

  • Muslimbek

I bought brand new A51, it is lightweight and has big screen. Unfortunatelly after 2-3 month it stopped charging, just showing charge icon but always remaining 0%. disappointed :-(

  • bella

i bought a brand new samsung A51 and im so dissappointed wth the sound quality. for music n notifications its OK, but on call sound sucks. even on speaker mode i cant hear. the voice is muffled plus internt doesnt work on mobile data ...

go for Mi. coz this one is not worth the price