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Samsung Galaxy A51 vs Galaxy A21s

Here we compared two smartphones: the 6.5-inch Samsung Galaxy A51 (with Exynos 9 Octa 9611) that was released on December 12, 2019, against the Samsung Galaxy A21s, which is powered by Exynos 850 and came out 6 months after. On this page, you will find tests, full specs, strengths, and weaknesses of each of the gadgets.

Key differences

An overview of the main advantages of each smartphone
Reasons to consider the Samsung Galaxy A51
  • 50% higher pixel density (405 vs 270 PPI)
  • 54% better performance in AnTuTu Benchmark (189K versus 123K)
  • Delivers 30% higher maximum brightness (631 against 487 nits)
  • Slow-motion recording at 960FPS
  • Ability to record video in 4K resolution
  • Super AMOLED display (versus competitor's PLS TFT)
  • The front-facing camera can record video at 4K
Reasons to consider the Samsung Galaxy A21s
  • Shows 38% longer battery life (119 vs 86 hours)
  • Comes with 1000 mAh larger battery capacity: 5000 vs 4000 mAh
  • More energy-efficient CPU – Exynos 850
  • The phone is 6-months newer

Review

Display
Screen quality, color accuracy, brightness
Performance
CPU/GPU performance in apps and games
Battery
Battery life, charging type and speed
Camera
Photo and video recording quality
Connectivity
Networks, ports, data transmission
NanoReview score
Final comparison evaluation

Value for money

You can enter your local price of these phones (in USD or any other currency) and click on the "Calculate" button to see which one has a better value for money.
Price

Tests and specifications

Comparison table of technical specifications and tests

Display

Type Super AMOLED PLS TFT
Size 6.5 inches 6.5 inches
Resolution 1080 x 2400 pixels 720 x 1600 pixels
Aspect ratio 20:9 20:9
PPI 405 ppi 270 ppi
Refresh rate 60 Hz 60 Hz
HDR support No No
Screen protection Corning Gorilla Glass 3 Tempered glass
Screen-to-body ratio 87.4% 82.8%
Display features - Always-On Display -
Display tests
RGB color space 98.8% 88.4%
PWM 242 Hz 500 Hz
Response time 25 ms 30.4 ms
Contrast ∞ Infinity 1500:1
Max. Brightness
Galaxy A51 +30%
631 nits
487 nits
Sources: NotebookCheck [1], [2]

Design and build

Height 158.5 mm (6.24 inches) 163.6 mm (6.44 inches)
Width 73.6 mm (2.9 inches) 75.3 mm (2.96 inches)
Thickness 7.9 mm (0.31 inches) 8.9 mm (0.35 inches)
Weight 172 gramm (6.07 oz) 192 gramm (6.77 oz)
Waterproof No No
Rear material Plastic Plastic
Frame material Plastic Plastic
Colors White, Black Black, Blue, Red
Fingerprint scanner Yes, in-display Yes, rear
Screen-to-body ratio
87.4%
82.8%

Performance

Tests of Samsung Galaxy A51 and Samsung Galaxy A21s in the benchmarks
SoC
Chipset Samsung Exynos 9 Octa 9611 Samsung Exynos 850
Max. clock 2300 MHz 2000 MHz
CPU cores 8 (4 + 4) 8 (8)
Architecture - 4 cores at 1.7 GHz: Cortex-A53
- 4 cores at 2.3 GHz: Cortex-A73
- 8 cores at 2 GHz: Cortex-A55
Lithography process 10 nanometers 8 nanometers
Graphics Mali-G72 MP3 Mali-G52 MP1
GPU clock 850 MHz 820 MHz
FLOPS ~259 GFLOPS ~26 GFLOPS
Memory
RAM size 4, 6 GB 3, 4 GB
Memory type LPDDR4X LPDDR4X
Memory clock 1866 MHz 1866 MHz
Channels 2 2
Storage
Storage size 64, 128 GB 32, 64 GB
Storage type UFS 2.0 eMMC 5.1
Memory card MicroSD MicroSD
Memory card max. size Up to 512 GB Up to 512 GB

Benchmarks

Geekbench 5 (Single-Core)
Galaxy A51 +86%
350
Geekbench 5 (Multi-Core)
Galaxy A51 +17%
1280
AnTuTu Benchmark 7
111489
AnTuTu Benchmark 8
Galaxy A51 +54%
189918
123129

Software

Operating system Android 10 (Can be upgraded to Android 11) Android 10 (Can be upgraded to Android 11)
ROM One UI 3.0 One UI 3.0
OS size 23 GB 12 GB

Battery

Specifications
Capacity 4000 mAh 5000 mAh
Charge power 15 W 15 W
Battery type Li-Po Li-Po
Replaceable No No
Wireless charging No No
Reverse charging No No
Fast charging Yes (40% in 35 min) Yes (50% in 60 min)
Full charging time 1:50 hr 2:10 hr

Battery life tests

Web browsing (Wi-Fi)
13:21 hr
18:02 hr
Watching videos (Player)
14:22 hr
17:29 hr
Talk (3G)
21:51 hr
39:38 hr

Camera

Specs and camera test of smartphones
Main camera
Matrix 48 megapixels 48 megapixels
Image resolution 8000 x 6000 8000 x 6000
Zoom Digital Digital
Flash LED LED
Stabilization Digital Digital
8K video recording No No
4K video recording Up to 30FPS No
1080p video recording Up to 30FPS Up to 30FPS
Slow motion 960 FPS (720p) No
Angle of widest lens 120° 123°
Lenses 4 (48 MP + 12 MP + 5 MP + 5 MP) 4 (48 MP + 8 MP + 2 MP + 2 MP)
Wide (main) lens - 48 MP
- Aperture: f/2.0
- Focal length: 26 mm
- Pixel size: 0.8 micron
- Sensor: 1/2", Samsung S5KGM2 (ISOCELL CMOS)
- Phase autofocus
- 48 MP
- Aperture: f/2.0
- Focal length: 26 mm
- Pixel size: 0.8 micron
- Sensor: 1/2.0" (CMOS)
- Phase autofocus
Ultra-wide lens - 12 MP
- Aperture: f/2.2
- Focal length: 13 mm
- Pixel size: 1.12 micron
- 8 MP
- Aperture: f/2.2
- Pixel size: 1.12 micron
- Sensor: 1/4.0" (CMOS)
Macro lens - 5 MP
- Aperture: f/2.4
- Focal length: 40 mm
- Pixel size: 1.12 micron
- 2 MP
- Aperture: f/2.4
Depth lens - 5 MP
- Aperture: f/2.2
- Pixel size: 1.12 micron
- Sensor: 1/5.0" (CMOS)
- 2 MP
- Aperture: f/2.4
Camera features - Bokeh mode
- Pro mode
- Bokeh mode
Selfie camera
Megapixels 32 megapixels 13 megapixels
Image resolution 6560 x 4928 4128 x 3096
Aperture f/2.2 f/2.2
Focal length 26 mm -
Pixel size 0.8 microns 1.12 microns
Sensor type ISOCELL CMOS CMOS
Sensor size 1/2.8" 1/3.1"
Video resolution 2160p (4K) при 30 FPS 1080p (Full HD) при 30 FPS

Connectivity

Wi-Fi standard Wi-Fi 5 (802.11 b/g/n/ac) Wi-Fi 5 (802.11 a/b/g/n/ac)
Wi-Fi features - Dual Band
- Wi-Fi Direct
- Wi-Fi Hotspot
- Wi-Fi Display
- Dual Band
- Wi-Fi Direct
- Wi-Fi Hotspot
- Wi-Fi Display
Bluetooth version 5 5
Bluetooth features PBAP/PAB, PAN, OPP, MAP, HSP, HID, HFP, DIP, AVRCP, A2DP PBAP/PAB, PAN, OPP, MAP, HSP, HID, HFP, DIP, AVRCP, A2DP
USB type USB Type-C USB Type-C
USB version 2 2
USB features - Charging
- USB-Storage mode
- OTG
- Charging
- USB-Storage mode
- OTG
GPS GPS, GLONASS, Beidou, Galileo GPS, GLONASS, Beidou, Galileo
NFC* Yes Yes
Infrared port No No
Network
Number of SIM* 2 2
Type of SIM card Nano Nano
Multi SIM mode Standby Standby
eSIM support* No No
Hybrid slot No No
LTE Cat* 12 13
5G support No No

Sound

Speakers Mono Mono
Headphone audio jack Yes Yes
FM radio Yes Yes
Dolby Atmos Yes Yes
Speakers test
Max. loudness
81.7 dB
79.5 dB

Other

Category Mid-range Budget
Announced December 2019 May 2020
Release date December 2019 June 2020
Launch price ~ 250 USD ~ 200 USD
SAR (head) 0.596 W/kg 0.23 W/kg
SAR (body) 1.45 W/kg 1.38 W/kg
Sensors - Proximity sensor
- Gyroscope
- Accelerometer
- Ambient light sensor
- Compass
- Fingerprint
- Hall-effect sensor
- Proximity sensor
- Gyroscope
- Accelerometer
- Ambient light sensor
- Compass
- Fingerprint
*Disclaimer! NFC, GSM network support, and some other specs can be different depending on the country.

Conclusion

After analyzing all the data, we think that the Samsung Galaxy A51 is definitely a better buy.

Cast your vote

So, which phone would you choose?
265 (55%)
217 (45%)
Total votes: 482

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