Samsung Galaxy M21s vs Samsung Galaxy S9

Network
2G network

GSM 850, 900, 1800, 1900

GSM 850, 900, 1800, 1900
3G network

HSDPA 850, 900, 1700(AWS), 1900, 2100

HSDPA 850, 900, 1700(AWS), 1900, 2100
4G network

LTE frequency band 1, 2, 3, 4, 5, 7, 8, 12, 13, 17, 20, 26, 28, 38, 40, 41, 66

LTE
HSDPA speed

42.2 Mbps

42.2 Mbps
HSUPA speed

5.76 Mbps

5.76 Mbps
LTE speed

LTE-A, 603 Mbps download, 150 Mbps upload

-
LTE-A speed

-

LTE-A, (6CA) Cat18, 1200 Mbps download, 200 Mbps upload
GPRS

Yes

Yes
EDGE

Yes

Yes

Design
Build

Glass front (Gorilla Glass 3), plastic back, plastic frame

Front/back glass (Gorilla Glass 5), aluminum frame
SIM

Single SIM (Nano-SIM) or Dual SIM (Nano-SIM, dual stand-by)

Single SIM (Nano-SIM) or Hybrid Dual SIM (Nano-SIM, dual stand-by)
Height

159.2 mm

147.7 mm
Width

75.1 mm

68.7 mm
Thickness

8.9 mm

8.5 mm
Weight

191 g

163 g
Payment

-

Samsung Pay(Visa, Mastercard certified)
Waterproof

-

IP68, 1.5m and 30 minutes
Dust proof

-

Yes, IP68
Colors

Black, Blue

Coral Blue, Lilac Purple, Midnight Black, Titanium Gray

Display
Display type

Super AMOLED

Super AMOLED capacitive touchscreen
Physical size

6.4 inches

5.8 inches
Resolution

1080 x 2340 pixels

1440 x 2960 pixels
Pixel density

403 ppi

570 ppi
Display colors

16777216

16777216
Protection

2.5D curved glass screen, Corning Gorilla Glass 3

Corning Gorilla Glass 5
Multitouch

-

Yes
Display features

420 nits (typ), Infinity U Display

HDR10 compliant, 3D Touch, Always-on display

Main camera
Camera type

Triple

-
Camera type

-

Photo / Video
Main camera

(wide) , 64 MP, f/1.8 , 26 mm, 1/1.72" , 0.8 µm

12 MP, f/1.5-2.4 , 26 mm, 1/2.5" , 1.4 µm
(ultrawide) , 8 MP, f/2.2 , 1/4.0" , 1.12 µm
(depth) , 5 MP, f/2.2
Primary camera resolution

9280 x 6920 pixels

4032 x 3024 pixels
Primary camera video

4K@30fps, 1080p@30fps, gyro-EIS

2160p@60fps, 1080p@240fps, 720p@960fps
Primary camera Autofocus

-

dual pixel phase detection autofocus
Primary camera flash

LED flash

LED flash
Primary camera optical image stabilization

-

optical image stabilization
Primary camera video dual video

-

dual-video record
Primary camera video hdr

-

HDR
Camera features

Autofocus, continuous shooting, digital zoom, geotagging, panorama, HDR, touch focus, face detection, white balance settings, ISO settings, exposure compensation, self-timer, scene-mode, phase detection autofocus

Auto HDR, Geo-tagging, face/smile detection, panorama, simultaneous 4K video and 9MP image recording, touch focus

Selfie camera
Selfie camera type

Single

-
Selfie camera

(wide) , 32 MP, f/2.0 , 26 mm, 1/2.8" , 0.8 µm

8 MP, f/1.7 , 25 mm, 1/3.6" , 1.22 µm
Selfie camera resolution

-

3264 x 2448 pixels
Secondary camera autofocus

-

autofocus
Secondary camera dual video call

-

dual video call
Secondary camera HDR

-

Auto HDR
Selfie camera video

1080p@30fps

1440p@30fps

Connectivity
WLAN

Wi-Fi 802.11a, 802.11b, 802.11g, 802.11n, 802.11n 5Ghz, 802.11ac

Wi-Fi 802.11a, 802.11b, 802.11g, 802.11n, 802.11ac
WLAN WiFi Hotspot

Yes

Yes
WLAN WiFi Direct

Yes

Yes
WLAN WiFi Dual Band

Yes

Yes
USB

Type-C 2.0

Type-C 1.0 reversible connector
Bluetooth

v5.0

v5.0
Bluetooth A2DP

Yes

Yes
bluetooth LE

Yes

Yes
Bluetooth AptX

-

Yes
NFC

No

Yes
GPS

Yes, with A-GPS

Yes, with A-GPS
GLONASS

Yes

Yes
GALILEO

Yes

Yes
BDS

Yes

Yes

Features
Messaging SMS

-

SMS(threaded view)
Messaging MMS

-

MMS
Messaging Email

-

Email
Messaging IM

-

IM
Messaging Push Mail

-

Push Mail
Sensors

Accelerometer, compass, fingerprint, gyroscope, proximity

Iris scanner, SpO2, accelerometer, barometer, compass, fingerprint (rear-mounted), gyro, heart rate, proximity