Samsung Galaxy S21 Ultra 5G vs Samsung Galaxy S25 Plus

Compare Samsung Galaxy S21 Ultra 5G vs Samsung Galaxy S25 Plus side by side: Exynos 2100 / Snapdragon 888 5G (5 nm) vs Qualcomm Snapdragon 8 Elite for Galaxy…

Samsung

Galaxy S25 Plus

$999

11categories won

6 categories tied · 22 scored in total · add a third phone

Information Gain

Which one wins?

MxMob Algorithmic Verdict

Samsung Galaxy S25 Plus takes the overall win

Overall Pick

The Samsung Galaxy S25 Plus proves superior overall against the Samsung Galaxy S21 Ultra 5G, outperforming on battery endurance and daily usability. In camera testing, the Galaxy S21 Ultra 5G leads with sharper imaging, while battery endurance leans towards the Galaxy S25 Plus. Choose the Galaxy S25 Plus if you want the highest performance ceiling, or opt for the Galaxy S21 Ultra 5G if its specific hardware strengths better fit your budget.

🔋 BatteryGalaxy S25 Plus

Galaxy S25 Plus takes battery honors offering 4,900 mAh alongside 45W charging.

🎮 GamingGalaxy S25 Plus

Galaxy S25 Plus provides greater sustained gaming output with its Qualcomm Snapdragon 8 Elite for Galaxy and 12GB RAM.

📸 CameraGalaxy S21 Ultra 5G

Galaxy S21 Ultra 5G wins photography with 108MP main imaging and 10x dedicated optical zoom.

🏷️ ValueGalaxy S25 Plus

Galaxy S25 Plus wins on budget and value at $999 compared to $1199.

Category verdicts are computed algorithmically from verified technical specifications and hardware benchmarks. Rows where neither figure is objectively better — screen size preference, operating system choice, aesthetic build materials — are displayed for direct reference without scoring bias.

Galaxy S21 Ultra 5G vs Galaxy S25 Plus: specifications compared

Display

Display comparison between the Samsung Galaxy S21 Ultra 5G, Samsung Galaxy S25 Plus
Specification	Galaxy S21 Ultra 5G	Galaxy S25 Plus
Screen size	6.8"	6.7"
Resolution	1440 x 3200Winner	1440 x 3120
Pixel density	516 ppi	513 ppi
Refresh rate	120 Hz	120 Hz
Peak brightness	1500 nits	2600 nitsWinner

Performance

Performance comparison between the Samsung Galaxy S21 Ultra 5G, Samsung Galaxy S25 Plus
Specification	Galaxy S21 Ultra 5G	Galaxy S25 Plus
Chipset	Exynos 2100 / Snapdragon 888 5G (5 nm)	Qualcomm Snapdragon 8 Elite for Galaxy
Process node	5 nm	3 nmWinner
AnTuTu score	870,000	3,080,000Winner
Geekbench multi	3800	9600Winner
Maximum RAM	12 GB	12 GB
Maximum storage	128GB	512GBWinner

Camera

Camera comparison between the Samsung Galaxy S21 Ultra 5G, Samsung Galaxy S25 Plus
Specification	Galaxy S21 Ultra 5G	Galaxy S25 Plus
Main sensor	108 MPWinner	50 MP
Rear cameras	4Winner	3
Optical zoom	10xWinner	3x
Ultrawide	12 MP	12 MP
Selfie camera	40 MPWinner	12 MP
Max video	8K at 24fps / 4K at 60fps all cameras	8K at 30fps

Battery and charging

Battery and charging comparison between the Samsung Galaxy S21 Ultra 5G, Samsung Galaxy S25 Plus
Specification	Galaxy S21 Ultra 5G	Galaxy S25 Plus
Capacity	5,000 mAh	4,900 mAh
Wired charging	25 W	45 WWinner
Wireless charging	15 W	15 W

Design

Design comparison between the Samsung Galaxy S21 Ultra 5G, Samsung Galaxy S25 Plus
Specification	Galaxy S21 Ultra 5G	Galaxy S25 Plus
Weight	227 g	190 gWinner
Thickness	8.9 mm	7.3 mmWinner
Water resistance	IP68	IP68
Build	Aluminum frame, Gorilla Glass Victus front and back	Enhanced Armor Aluminum frame, Corning Gorilla Glass Victus 2 front and back

Software and support

Software and support comparison between the Samsung Galaxy S21 Ultra 5G, Samsung Galaxy S25 Plus
Specification	Galaxy S21 Ultra 5G	Galaxy S25 Plus
Operating system	Android 11	Android 15
OS updates	4 years	7 yearsWinner
Security updates	5 years	7 yearsWinner

Connectivity and value

Connectivity and value comparison between the Samsung Galaxy S21 Ultra 5G, Samsung Galaxy S25 Plus
Specification	Galaxy S21 Ultra 5G	Galaxy S25 Plus
5G	Yes	Yes
Wi-Fi	Wi-Fi 6E (802.11ax)	Wi-Fi 7 (802.11be)
Storage expansion	None	None
3.5mm jack	No	No
Launch price	$1,199	$999Winner