Samsung S21 Ultra vs S25 Ultra – Check Which One Is Best & Why?

Samsung Galaxy S25 Ultra & Samsung Galaxy S21 Ultra share many similarities, but there are also important differences, such as quality, performance, features, design, and connectivity. If you want the best one between them, I Would recommend the Samsung Galaxy S25 Ultra rather than the Samsung Galaxy S21 Ultra. 

Why Do I Recommend The Samsung Galaxy S25 Ultra

  • The Samsung Galaxy S25 Ultra has a Snapdragon 8 Gen 4 chipset that delivers up to 35 % faster multitasking performance and longer battery life during heavy gaming, compared to the Galaxy S21 Ultra’s  Snapdragon 888.
  • Samsung Galaxy S25 Ultra features a 6.9-inch Dynamic AMOLED 2X display with 2,600-nit peak brightness that keeps HDR content clear in direct sunlight, compared to the Galaxy S21 Ultra’s 1,500-nit panel.
  • It includes a 200 MP main camera with advanced AI image processing that captures sharper night photos and 8K30 video, while the Galaxy S21 Ultra has 108 MP sensor with 8K24 recording.
  • The Samsung Galaxy S25 Ultra supports 45 W wired charging that refills the 5,000 mAh battery to 65 % in 30 minutes, reducing downtime on busy days, compared to the Galaxy S21 Ultra’s 25 W system.
  • Samsung Galaxy S25 Ultra has LPDDR5X RAM and UFS 4.0 storage that load apps and transfer files up to twice as fast, compared to the Galaxy S21 Ultra’s LPDDR5 and UFS 3.1 hardware.
  • It comes with a titanium frame and Gorilla Glass Armor 2 that withstand harder drops and resist scratches better, compared to the Galaxy S21 Ultra’s aluminum frame and Gorilla Glass Victus.
  • The Samsung Galaxy S25 Ultra supports Wi-Fi 7 and Bluetooth 5.4 with LE Audio that deliver gigabit-class wireless speeds and high-fidelity Auracast streaming, compared to the Galaxy S21 Ultra’s Wi-Fi 6 and Bluetooth 5.1.
  • Samsung Galaxy S25 Ultra includes a seven-year Android update commitment that keeps security patches and new features coming through 2032, compared to the Galaxy S21 Ultra’s four-year coverage.

Maybe the Samsung Galaxy S21 Ultra price can make you comfortable because it’s a little bit cheaper than the Samsung Galaxy S25 Ultra. But you have to compromise all the above-mentioned features. Now the Decision is Yours. I hope it was helpful to choose the right one.

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Side By Side Comparison

FeatureSamsung Galaxy S25 UltraSamsung Galaxy S21 Ultra
ChipsetSnapdragon 8 Gen 4 for Galaxy (3 nm)Snapdragon 888 (5 nm)
CPU Cores2× Oryon @ 4.47 GHz1× Kryo 680 @ 2.84 GHz
GPUAdreno 830Adreno 660
Frame MaterialTitaniumArmor Aluminum
Front/Back GlassGorilla Glass Armor 2Gorilla Glass Victus
Display Size6.9 inches6.8 inches
Peak Brightness2600 nits1500 nits
Screen-to-Body Ratio90.3%89.3%
RAM TypeLPDDR5XLPDDR5
Storage TypeUFS 4.0UFS 3.1
Base Storage256 GB128 GB
Max Storage1 TB512 GB
Battery ChemistryLi-IonLi-Polymer
Charging Speed45W wired25W wired
Wireless ChargingQi2 / Fast WirelessQi / Fast Wireless
Reverse Wireless Charging15W4.5W
Estimated Battery Life (Browsing)~20h 49m~14h 43m
Main Camera200 MP, f/1.7108 MP, f/1.8
Ultrawide Camera50 MP, f/1.912 MP, f/2.2
Periscope Telephoto50 MP 5x10 MP 10x
Telephoto 2Removed10 MP 3x
Max Video Resolution8K@30fps8K@24fps
4K Slow Motion4K@120fps4K@60fps
Bluetooth Version5.45.1
PriceCheck S25 Ultra PriceCheck S21 Ultra Price

What Common Both Can Do?

  • Dynamic AMOLED 2X Display: Both devices feature Samsung’s premium Dynamic AMOLED 2X panels, known for deep blacks, vibrant colors, and excellent contrast. They both support adaptive refresh rates up to 120Hz and deliver stunning visuals with QHD+ resolution for ultra-sharp clarity.
  • HDR10+ and Always-On Display: HDR10+ enhances dynamic range for supported video content, delivering deeper contrast and better highlights. Both models support Always-On Display to show time, notifications, and battery without waking the screen.
  • S Pen Support (Built-in): The S25 Ultra and S21 Ultra both include full S Pen integration, allowing users to draw, write, and navigate with precision. The pen is embedded in the phone chassis on both models, making it easy to store and access.
  • Battery Capacity: Each device features a 5,000 mAh battery, which is the maximum found in Galaxy phones. This ensures all-day usage even with demanding tasks.
  • Wireless and Reverse Wireless Charging: Wireless charging keeps cords at bay, and both phones also support reverse wireless charging—allowing you to charge earbuds, watches, or other Qi-enabled devices directly from the phone.
  • IP68 Water & Dust Resistance: Both phones are IP68-certified, meaning they are protected from dust and can be submerged in up to 1.5 meters of water for up to 30 minutes.
  • Ultrasonic Fingerprint Sensor: Samsung uses its secure and fast in-display ultrasonic fingerprint scanner in both models, enabling convenient biometric authentication.
  • Samsung DeX Wireless: DeX mode turns the phone into a desktop-like experience when connected to a monitor wirelessly, available on both phones for multitasking and productivity on the go.
  • Samsung Knox Security: Built-in defense-grade security through Samsung Knox protects data, apps, and the OS integrity. Both phones include Secure Folder support for storing private content.
  • Stereo Speakers Tuned by AKG: Each device features a dual-speaker setup tuned by AKG with support for Dolby Atmos, enhancing audio quality for media, games, and calls.
  • 5G Connectivity: Both phones support full 5G networks (sub-6GHz and mmWave), delivering ultra-fast downloads and low-latency mobile internet access.
  • USB-C 3.2 Port: Each model uses a USB-C 3.2 port, which supports fast data transfer speeds and high-speed wired charging capabilities.

Common Features

FeatureSamsung Galaxy S25 UltraSamsung Galaxy S21 Ultra
Device TypeFlagship SmartphoneFlagship Smartphone
Display TypeDynamic AMOLED 2XDynamic AMOLED 2X
Refresh RateUp to 120Hz (Adaptive)Up to 120Hz (Adaptive)
Resolution ClassQHD+ (1440p)QHD+ (1440p)
HDR SupportHDR10+HDR10+
Always-on DisplayYesYes
S Pen SupportYesYes
Battery Capacity5,000 mAh5,000 mAh
Wireless ChargingYesYes
Reverse Wireless ChargingYesYes
IP RatingIP68IP68
BiometricsUltrasonic Fingerprint SensorUltrasonic Fingerprint Sensor
Samsung DeXWireless DeX supportedWireless DeX supported
Samsung KnoxYesYes
Stereo SpeakersYes, AKG-tunedYes, AKG-tuned
5G ConnectivityYesYes
USB PortUSB-C 3.2USB-C 3.2
Price Check S25 Ultra Price Check S21 Ultra Price

FAQ

Does the Samsung Galaxy S25 Ultra have a better processor than the Galaxy S21 Ultra?
Yes, the Galaxy S25 Ultra features the Snapdragon 8 Gen 4 for Galaxy built on a 3nm process, delivering significantly better performance and power efficiency compared to the 5nm Snapdragon 888 found in the Galaxy S21 Ultra.

Is the Galaxy S25 Ultra more durable than the Galaxy S21 Ultra?
Yes, the Galaxy S25 Ultra uses a titanium frame and Gorilla Glass Armor 2, which improves drop and scratch resistance, while the Galaxy S21 Ultra features an aluminum frame with Gorilla Glass Victus.

Do both phones support the S Pen?
Yes, both the Galaxy S25 Ultra and Galaxy S21 Ultra support the S Pen and include a built-in slot for storing it inside the phone.

Which device has better camera hardware?
The Galaxy S25 Ultra has upgraded camera hardware with a 200 MP main sensor, 50 MP ultrawide, and 50 MP periscope telephoto, compared to the Galaxy S21 Ultra’s 108 MP main sensor, 12 MP ultrawide, and dual 10 MP telephoto lenses.

Is there a difference in display quality between the two models?
Yes, the Galaxy S25 Ultra offers a brighter display with peak brightness of 2600 nits and a slightly larger 6.9-inch screen, while the Galaxy S21 Ultra has a 6.8-inch display with a peak of 1500 nits.

Do both phones support wireless and reverse wireless charging?
Yes, both models support wireless charging and reverse wireless charging, though the S25 Ultra supports faster wireless and reverse charging speeds compared to the S21 Ultra.

Which phone has longer software support?
The Galaxy S25 Ultra will receive up to 7 years of Android OS and security updates, while the Galaxy S21 Ultra is expected to stop receiving major updates after Android 16.

Do both phones come with 5G connectivity?
Yes, both the Galaxy S25 Ultra and Galaxy S21 Ultra support 5G, including both sub-6GHz and mmWave bands for global connectivity.

Is the battery capacity the same on both phones?
Yes, both devices include a 5000 mAh battery, but the S25 Ultra offers better power efficiency and longer screen-on time due to its newer chip and software optimization.

Can I use Samsung DeX on both devices?
Yes, both the Galaxy S25 Ultra and Galaxy S21 Ultra support Samsung DeX, including wireless DeX functionality for desktop-style multitasking.

Which phone supports higher wired charging speeds?
The Galaxy S25 Ultra supports up to 45W wired charging, while the Galaxy S21 Ultra supports up to 25W, making the newer model faster to recharge.

Does the Galaxy S25 Ultra have better connectivity features?
Yes, the Galaxy S25 Ultra supports Wi-Fi 7, Bluetooth 5.4, and Auracast, which are more advanced than the Wi-Fi 6 and Bluetooth 5.1 found in the Galaxy S21 Ultra.

Is the front camera better on the S25 Ultra?
While the Galaxy S21 Ultra has a higher resolution 40 MP front camera, the Galaxy S25 Ultra uses a 12 MP sensor optimized with AI enhancements for improved selfies and video processing.

Do both phones have the same IP rating for water and dust resistance?
Yes, both the Galaxy S25 Ultra and Galaxy S21 Ultra are rated IP68, meaning they can withstand submersion in water and are fully dust-resistant.

Is there satellite communication on either device?
The Galaxy S25 Ultra includes support for satellite-based emergency texting, a feature not available on the Galaxy S21 Ultra.