Samsung Galaxy A21 vs Xiaomi Redmi Note 9 Pro vs Samsung Galaxy A51

Compare phone and tablet specifications of up to three devices at once.

Display

Size:

6.5 inches
6.7 inches
6.5 inches

Resolution:

1600 x 720 pixels, 20:9 ratio, 270 PPI
2400 x 1080 pixels, 20:9 ratio, 395 PPI
2400 x 1080 pixels, 20:9 ratio, 405 PPI

Technology:

IPS LCD
IPS LCD
Super AMOLED

Screen-to-body:

79.20 %
84.42 %
87.37 %

Features:

60Hz refresh rate, Ambient light sensor, Proximity sensor
Scratch-resistant glass (Corning Gorilla Glass 5), Ambient light sensor, Proximity sensor
60Hz refresh rate, Scratch-resistant glass (Corning Gorilla Glass 3), Ambient light sensor, Proximity sensor

Hardware

System chip:

Mediatek Helio P35
Qualcomm Snapdragon 720G SM7125
Samsung Exynos 9611

Processor:

Octa-core, 2300 MHz, Arm Cortex-A53, 64-bit, 12 nm
Octa-core, 2300 MHz, Kryo 465, 64-bit, 8 nm
Octa-core, 2300 MHz, ARM Cortex-A73 and ARM Cortex-A53, 64-bit, 10 nm

GPU:

PowerVR GE8320
Adreno 618
Mali-G72 MP3

RAM:

3GB LPDDR4
6GB LPDDR4
4GB LPDDR4

Internal storage:

32GB (eMMC 5.1), available to use: 19.8 GB
64GB (UFS 2.1)
128GB, available to use: 105.9 GB

Storage expansion:

microSDXC up to 512 GB
microSDXC up to 512 GB
microSDXC up to 512 GB

Device type:

Smartphone
Smartphone
Smartphone

OS:

Android (10), Samsung One UI
Android (10), Xiaomi MI UI
Android (10), Samsung One UI

Battery

Capacity:

4000 mAh
5020 mAh
4000 mAh

Type:

Li - Polymer, Not user replaceable
Li - Polymer, Not user replaceable
Li - Polymer, Not user replaceable

Battery life test results:

Charging:

Fast charging
Fast charging
Fast charging

Max charge speed:

Wired: 15.0W
Wired: 30.0W

Camera

Rear:

Quad camera
Quad camera
Quad camera

Main camera:

16 MP (PDAF)
64 MP (PDAF)
48 MP (PDAF)

Specifications:

Aperture size: F1.8; Sensor size: 1/3.06"; Pixel size: 1 μm
Aperture size: F1.9; Focal length: 26 mm; Sensor size: 1/1.7"; Pixel size: 0.8 μm
Aperture size: F2.0; Focal length: 26 mm; Sensor size: 1/2"; Pixel size: 0.8 μm

Second camera:

8 MP (Ultra-wide)
8 MP (Ultra-wide)
12 MP (Ultra-wide)

Specifications:

Aperture size: F2.2; Sensor size: 1/4"; Pixel size: 1.12 μm
Aperture size: F2.2; Focal Length: 13 mm; Sensor size: 1/4"; Pixel size: 1.12 μm
Aperture size: F2.2; Focal Length: 13 mm; Pixel size: 1.12 μm

Third camera:

2 MP (Macro)
5 MP (Macro, Autofocus)
5 MP (Macro)

Specifications:

Aperture size: F2.4
Aperture size: F2.4; Sensor size: 1/5"; Pixel size: 1.12 μm
Aperture size: F2.4; Focal Length: 40 mm

Fourth camera:

2 MP (Depth information)
2 MP (Depth information)
5 MP (Depth information)

Specifications:

Aperture size: F2.4
Aperture size: F2.4; Sensor size: 1/5"; Pixel size: 1.75 μm
Aperture size: F2.2; Sensor size: 1/5"; Pixel size: 1.12 μm

Video recording:

1920x1080 (Full HD) (30 fps)
3840x2160 (4K UHD) (30 fps), 1920x1080 (Full HD) (120 fps), 1280x720 (HD) (960 fps)
3840x2160 (4K UHD) (30 fps), 1920x1080 (Full HD) (120 fps), 1280x720 (HD) (240 fps)

Features:

Hyperlapse, EIS

Front:

13 MP
16 MP (HDR, Slow-motion videos)
32 MP (HDR)

Video capture:

1920x1080 (Full HD)
1920x1080 (Full HD)
1920x1080 (Full HD)

Design

Dimensions:

6.61 x 3.02 x 0.32 inches (167.8 x 76.7 x 8.1 mm)
6.53 x 3.02 x 0.35 inches (165.8 x 76.7 x 8.8 mm)
6.24 x 2.90 x 0.31 inches (158.5 x 73.6 x 7.9 mm)

Weight:

6.81 oz (193.0 g)
7.37 oz (209.0 g)
6.07 oz (172.0 g)

Materials:

Back: Plastic; Frame: Plastic
Back: Glass (Corning Gorilla Glass 5); Frame: Plastic
Back: Plastic; Frame: Plastic

Biometrics:

Fingerprint (touch)
Fingerprint (touch)
2D Face unlock, In-screen fingerprint

Keys:

Right: Volume control, Lock/Unlock key
Right: Volume control, Lock/Unlock key
Right: Volume control, Lock/Unlock key

Colors:

Black
Interstellar gray, Tropical green, Glacier white
Prism Crush black, Prism Crush white, Prism Crush pink, Prism Crush blue

Cellular

LTE (FDD):

Bands 1(2100), 2(1900), 3(1800), 4(AWS-1), 5(850), 7(2600), 8(900), 12(700 a), 13(700 c), 17(700 b), 20(800 DD), 25(1900+), 26(850+), 28(700 APT), 66(AWS-3), 71(600)
Bands 1(2100), 2(1900), 3(1800), 4(AWS-1), 5(850), 7(2600), 8(900), 20(800 DD), 28(700 APT)
Bands 1(2100), 2(1900), 3(1800), 4(AWS-1), 5(850), 7(2600), 8(900), 12(700 a), 13(700 c), 14(700 PS), 20(800 DD), 25(1900+), 26(850+), 28(700 APT), 29(700 d), 30(2300 WCS), 66(AWS-3), 71(600)

LTE (TDD):

Bands 38(2600), 39(1900+), 40(2300), 41(2600+)
Bands 38(2600), 40(2300), 41(2600+)
Bands 38(2600), 39(1900+), 41(2600+)

UMTS:

850, 900, 1700/2100, 1900, 2100 MHz
850, 900, 1700/2100, 1900, 2100 MHz
850, 900, 1700/2100, 1900, 2100 MHz

Data Speed:

LTE-A Cat 6 (300/50 Mbit/s), HSDPA+ (4G) 42.2 Mbit/s, HSUPA 5.76 Mbit/s
LTE-A, HSDPA+ (4G) 42.2 Mbit/s, HSUPA 5.76 Mbit/s
LTE-A, HSDPA+ (4G) 42.2 Mbit/s, HSUPA 5.76 Mbit/s

Dual SIM:

Yes

SIM type:

Nano SIM
Nano SIM
Nano SIM

HD Voice:

Yes
Yes

VoLTE:

Yes

Multimedia

Headphones:

3.5mm jack
3.5mm jack
3.5mm jack

Speakers:

Earpiece, Loudspeaker
Earpiece, Loudspeaker
Earpiece, Loudspeaker

Features:

Dolby Atmos

Screen mirroring:

Wireless screen share
Wireless screen share
Wireless screen share

Radio:

FM
FM

Additional microphone(s):

for Noise cancellation
for Noise cancellation

Connectivity & Features

Bluetooth:

5.0
5.0
5.0

Wi-Fi:

802.11 a, b, g, n, ac, dual-band; Wi-Fi Direct, Hotspot
802.11 a, b, g, n, ac, dual-band; Wi-Fi Direct, Hotspot
802.11 a, b, g, n, ac, dual-band; Wi-Fi Direct, Hotspot

USB:

Type-C (reversible), USB 2.0
Type-C (reversible), USB 2.0
Type-C (reversible), USB 2.0

Features:

Charging
Charging
Charging, OTG

Location:

GPS, A-GPS, Glonass, BeiDou, Cell ID, Wi-Fi positioning
GPS, A-GPS, Glonass, Galileo, BeiDou, Cell ID, Wi-Fi positioning
GPS, A-GPS, Glonass, Galileo, BeiDou, Cell ID, Wi-Fi positioning

Sensors:

Accelerometer, Gyroscope, Compass
Accelerometer, Gyroscope, Compass
Accelerometer, Gyroscope, Compass, Hall (for flip covers)

Other:

NFC
NFC, Infrared
NFC, ANT+

Hearing aid compatible:

M4, T3

Regulatory Approval

FCC approval:

Date approved:

Apr 17, 2020
Nov 28, 2019

FCC ID value:

ZCASMA215U link
A3LSMA515FN link

Measured SAR:

Head:

0.42 W/kg
0.89 W/kg

Body:

1.27 W/kg
1.18 W/kg

Simultaneous Transmission:

1.27 W/kg
1.56 W/kg

Wireless Router:

1.27 W/kg
1.12 W/kg

Phablet:

2.76 W/kg

Buyers information

Price:

$ 250
$ 400

User Manual:

This is the official Samsu​ng Galaxy A51 User Guide in English provided from the manufacturer.

In The Box:

This is the official Samsu​ng Galaxy A21 User Guide in English provided from the manufacturer.
33W Power adapter, Simple protective cover, USB Type-C cable, SIM eject tool, User guide, Warranty card

Availability

Officially announced:

Apr 08, 2020
Apr 30, 2020
Dec 12, 2019
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