Samsung Galaxy S21 Ultra (SM-G998U1 256GB) vs Samsung Galaxy S25 (SM-S931B/DS 256GB)
Side by side comparison between Samsung Galaxy S21 Ultra vs Samsung Galaxy S25 phones, differences, pros, cons and full specifications. What's the better?
,
6.8"
AMOLED
AMOLED
1440x3200
108
MP
MP
40mp
12GB
RAM
RAM
Octa-core
5000
mAh
mAh
(Non removable)
vs
6.2"
AMOLED
AMOLED
1080x2340
50
MP
MP
12mp
12GB
RAM
RAM
Octa-core
4000
mAh
mAh
(Non removable)
What's the better phone? Samsung Galaxy S21 Ultra (SM-G998U1 256GB)
The phonemore's choice is much more technical than personal. Therefore, you shouldn't only consider this. Our goal is to help you, but what's important to us may not be important to you. You decide which one is the best! Comment!
10 Advantages 
7 Advantages | 44 Common items in both devices |
| 12GB LPDDR5 / 12GB LPDDR5X |
| 256GB (220GB available) / 256GB (223GB available) |
| Aluminum frame, glass front/back |
| Dynamic AMOLED / LTPO AMOLED |
| HDR10+ |
| 120Hz |
| 16 million |
| +37 specs and more in the table below |
Check the comparison table below for more items that are not evaluated in comparison score above.
Highlight differences Clear highlight📱 Model features | ||
| Galaxy S21 Ultra (SM-G998U1 256GB) | Galaxy S25 (SM-S931B/DS 256GB) | |
| Model | Galaxy S21 Ultra (SM-G998U1 256GB) | Galaxy S25 (SM-S931B/DS 256GB) |
| Other model names | Galaxy S21 Ultra 5G (SM-G998U1) Unlocked | Galaxy S25 SM-S931B/Dual-SIM |
| Country or region available |  USA |  (Global, International) |
| Brand | Samsung | Samsung |
| Release date | 1/29/2021, Announced: 1/14/2021 | 2/3/2025, Announced: 1/22/2025 |
| Depth | 8.9 millimeters (0.35 inches) | 7.2 millimeters (0.28 inches) |
| Size (width x height) | 75.6 x 165.1 millimeters (2.98 x 6.5 in) | 70.5 x 146.9 millimeters (2.78 x 5.78 in) |
| Weight | 227 grams (7.95 ounces) | 162 grams (5.67 ounces) |
| Build, materials | Aluminum frame, glass front/back | Aluminum frame, glass front/back Back: Gorilla Glass Victus 2 |
| Protection against water and others | IP68 certified: water-resistant up to 1.5 meters for 30min and dust-resistant | IP68 certified: water-resistant up to 1.5 meters for 30min and dust-resistant |
📲 Display | ||
| Galaxy S21 Ultra (SM-G998U1 256GB) | Galaxy S25 (SM-S931B/DS 256GB) | |
| Display type | Dynamic AMOLED | LTPO AMOLED |
| Screen size | 6.8" inches | 6.2" inches |
| Screen-to-body ratio | ~89.4% (screen-to-body ratio) | ~91.1% (screen-to-body ratio) |
| Display resolution | 1440x3200 pixels (20:9) | 1080x2340 pixels (19.5:9) |
| Touchscreen | Capacitive Multitouch 10-points | Capacitive Multitouch 10-points |
| Pixel density (dot pitch) | 516 PPI | 416 PPI |
| Colors | 16 million | 16 million |
| Scratch-resistant glass | Gorilla Glass Victus | Gorilla Glass Victus 2 |
| Refresh rate | 120Hz | 120Hz |
| Display features | 1500nits[peak] HDR10+ Always-On Display | 2600nits[peak] HDR10+ Always-On Display |
🤖 Operating System | ||
| Galaxy S21 Ultra (SM-G998U1 256GB) | Galaxy S25 (SM-S931B/DS 256GB) | |
| System version | Android 11 | Android 15 |
| Firmware update | Android 14 | feature not registered |
| User Interface | One UI 3.1 / 4.1 / 5.1 / 6.0 | One UI 7.0 |
⚙️ Processor | ||
| Galaxy S21 Ultra (SM-G998U1 256GB) | Galaxy S25 (SM-S931B/DS 256GB) | |
| Chipset | 64bit: Qualcomm Snapdragon 888 (SM8350) (5nm) | 64bit: Qualcomm Snapdragon 8 Elite (SM8750-AB) (3nm) |
| CPU | Octa-core, 3 processors: 1x 2.84GHz Kryo 680 (Single-core) 3x 2.42GHz Kryo 680 (Triple-core) 4x 1.8GHz Kryo 680 (Quad-core) | Octa-core, 2 processors: 2x 4.47GHz Oryon V2 Phoenix L (Dual-core) 6x 3.53GHz Oryon V2 Phoenix M (Hexa-core) |
| GPU graphical controller | Qualcomm Adreno 660 (840MHz) | Qualcomm Adreno 830 (1100MHz) |
| Performance (benchmark) | AnTuTu: 681099 (v8), 809165 (v9) Geekbench: 3539 (v5.2) GFXBench: 54fps (ES 3.1 onscreen) | AnTuTu: 2193701 (v10) Geekbench: 10050 (v6) |
💽 Memory and storage | ||
| Galaxy S21 Ultra (SM-G998U1 256GB) | Galaxy S25 (SM-S931B/DS 256GB) | |
| RAM memory | 12GB LPDDR5 | 12GB LPDDR5X |
| Internal storage | 256GB (220GB available) UFS 3.1 | 256GB (223GB available) UFS 4.0 |
| External storage | Not supported | Not supported |
📶 Mobile networks | ||
| Galaxy S21 Ultra (SM-G998U1 256GB) | Galaxy S25 (SM-S931B/DS 256GB) | |
| Dual-SIM | Dual-SIM Standby - Call active on one sim card | Dual-SIM Standby - Call active on one sim card |
| SIM card | 1 slot (Single-SIM) nano-SIM (4FF) + e-SIM | 2 slots (Dual-SIM) nano-SIM (4FF) + e-SIM |
| Maximum Download / Upload | 5000/1920 Mbps | 3000/1024 Mbps |
| Network technology | 2G, 3G, 4G, 5G | 2G, 3G, 4G, 5G |
| Frequency, bands | Expand band details Collapse details | |
| GSM MHz band | Quad-Band 850/900/1800/1900 | Quad-Band 850/900/1800/1900 |
| Primary 2G network | CDMA 800/1900, GSM 850/900/1800/1900 | CDMA 800/1900, GSM 850/900/1800/1900 |
| Primary 3G network | CDMA2000 1xEV-DO UMTS 850/900/1700/1900/2100 | CDMA2000 1xEV-DO TD-SCDMA 1900/2000 UMTS 850/900/1700/1900/2100 |
| Primary 4G network | LTE Cat20 (1, 2, 3, 4, 5, 7, 8, 12, 13, 14, 18, 19, 20, 25, 26, 28, 30, 66, 71) TD-LTE (38, 39, 40, 41, 46, 48) VoLTE | LTE Cat24 (1, 2, 3, 4, 5, 7, 8, 12, 13, 17, 18 , 19, 20, 25, 26, 28, 66) TD-LTE (38, 39, 40, 41) VoLTE |
| Primary 5G network | SA/NSA/Sub6 (2, 5, 25, 41, 66, 71) mmWave (260, 261) | SA/NSA/Sub6 (1, 2, 3, 5, 7, 8, 12, 20, 25, 26, 28, 38, 40, 41, 66, 75, 77, 78) |
| Primary data network | GPRS, EDGE, CDMA2000 EV-DO Rev 0, CDMA2000 EV-DO Rev A, UMTS, HSDPA, HSUPA, HSPA+, TD-LTE, LTE, LTE-A, SA/NSA, Sub6 | GPRS, EDGE, CDMA2000 EV-DO Rev 0, CDMA2000 EV-DO Rev A, TD-SCDMA, UMTS, TD-HSDPA, HSDPA, HSUPA, HSPA+, TD-LTE, LTE, LTE-A, SA/NSA, Sub6 |
| Secondary 2G network | CDMA 800/1900, GSM 850/900/1800/1900 | CDMA 800/1900, GSM 850/900/1800/1900 |
| Secondary 3G network | CDMA2000 1xEV-DO UMTS 850/900/1700/1900/2100 | CDMA2000 1xEV-DO TD-SCDMA 1900/2000 UMTS 850/900/1700/1900/2100 |
| Secondary 4G network | LTE Cat20 (1, 2, 3, 4, 5, 7, 8, 12, 13, 14, 18, 19, 20, 25, 26, 28, 30, 66, 71) TD-LTE (38, 39, 40, 41, 46, 48) VoLTE | LTE Cat24 (1, 2, 3, 4, 5, 7, 8, 12, 13, 17, 18 , 19, 20, 25, 26, 28, 66) TD-LTE (38, 39, 40, 41) VoLTE |
| Secondary data network | GPRS, EDGE, CDMA2000 EV-DO Rev 0, CDMA2000 EV-DO Rev A, UMTS, HSDPA, HSUPA, HSPA+, TD-LTE, LTE, LTE-A, SA/NSA, Sub6 | GPRS, EDGE, CDMA2000 EV-DO Rev 0, CDMA2000 EV-DO Rev A, TD-SCDMA, UMTS, TD-HSDPA, HSDPA, HSUPA, HSPA+, TD-LTE, LTE, LTE-A, SA/NSA, Sub6 |
📷 Camera | ||
| Galaxy S21 Ultra (SM-G998U1 256GB) | Galaxy S25 (SM-S931B/DS 256GB) | |
| Back camera (main camera) | (quad camera) 108 megapixels 10MP periscope telephoto f/4.9240mm1/3.24"1.22µmPDAFOIS10x-optical-zoom 10MP telephoto f/2.470mm1/3.24"1.22µmPDAFOIS3x-optical-zoom 12MP ultrawide f/2.213mm1/2.55"1.4µmPDAFSuper-Steady-video | (triple camera) 50 megapixels 10MP telephoto f/2.467mm1/3.94"1.0µmPDAFOIS3x-optical-zoom 12MP ultrawide f/2.213mm120°1/2.55"1.4µmSuper-Steady |
| Main camera resolution | 12000x9000 pixels | 8160x6120 pixels |
| Video recording (primary) | 8K UHD (7680x4320) 24 fps | 8K UHD (7680x4320) 30 fps |
| Flash | LED flash | LED flash |
| Focal aperture | f/1.8 (aperture) | f/1.8 (aperture) |
| Focal length | 26mm (lens) | 24mm (lens) |
| Sensor size | 1/1.33" inches | 1/1.56" inches |
| Pixel size | 1.8µm pixel | 1µm pixel |
| Autofocus | PDAF: phase detection autofocus on both cameras | PDAF: phase detection autofocus on both cameras |
| Touch focus | Supported | Supported |
| Image stabilization | OIS: Optical stabilization | OIS: Optical stabilization |
| Zoom | Digital and optical zoom | Digital and optical zoom |
| Face/smile detection | Face detection, Smile detection | Face detection, Smile detection |
| BSI sensor | Supported | Supported |
| HDR | HDR photo/video on both cameras | HDR photo/video and HDR photo on front camera |
| Camera extras | 4K@60fps 1080p@240fps 720p@960fps | 8K@24/30fps 4K@30/60fps 1080p@30/60/240fps 10-bit HDR10+ |
📸 Front camera | ||
| Galaxy S21 Ultra (SM-G998U1 256GB) | Galaxy S25 (SM-S931B/DS 256GB) | |
| Front camera (secondary) | 40 megapixels | 12 megapixels |
| Front camera resolution | 7296x5472 pixels | 4000x3000 pixels |
| Video recording (secondary) | 4K UHD (3840x2160) | 4K UHD (3840x2160) |
| Front flash | Not supported | Not supported |
| Focal aperture | f/2.2 (aperture) | f/2.2 (aperture) |
| Focal length | 26mm (lens) | 26mm (lens) |
| Sensor size | 1/2.8" inches | 1/3.2" inches |
| Pixel size | 0.7µm pixel | 1.12µm pixel |
🔉 Sound and multimedia | ||
| Galaxy S21 Ultra (SM-G998U1 256GB) | Galaxy S25 (SM-S931B/DS 256GB) | |
| Loudspeaker | Stereo sound 32-bit/384kHz Dolby Atmos Tuned by AKG | Stereo sound 32-bit/384kHz Tuned by AKG |
| Active noise cancellation | 3 microphones | 3 microphones |
| Radio | FM | Not supported |
| TV | Not supported | Not supported |
| Video formats | MP4, H.265, H.264, H.263, XviD, MKV | MP4, H.265, H.264, H.263, XviD, MKV |
| Audio formats | MP3, WAV, WMA, eAAC+, FLAC | MP3, WAV, WMA, eAAC+, FLAC |
🔌 Connectivity | ||
| Galaxy S21 Ultra (SM-G998U1 256GB) | Galaxy S25 (SM-S931B/DS 256GB) | |
| USB | USB 3.2 Type-C, USB OTG On-The-Go | USB 3.2 Type-C, USB OTG On-The-Go |
| Audio output | Type-C reversible connector | Type-C reversible connector |
| TV output | USB Type-C (reversible) | USB Type-C (reversible) |
| Bluetooth | 5.2 + A2DP/LE | 5.4 + A2DP/LE |
| WiFi | 802.11 a/b/g/n/ac/ax [wifi6] (2.4GHz, 5GHz) + MIMO WiFi Direct, hotspot | 802.11 a/b/g/n/ac/ax/be [wifi7/6E/6] (2.4GHz, 5GHz, 6GHz) + MIMO WiFi Direct, hotspot |
| DLNA | Supported | Supported |
| GPS | A-GPS, GeoTagging, GLONASS, GALILEO, BeiDou | A-GPS, GeoTagging, GLONASS, GALILEO, BeiDou, QZSS |
| NFC | Supported | Supported |
| Infrared port | Not supported | Not supported |
🧭 Sensors | ||
| Galaxy S21 Ultra (SM-G998U1 256GB) | Galaxy S25 (SM-S931B/DS 256GB) | |
| Sensors | Accelerometer Ambient light sensor Barometer Compass Face unlock Fingerprint sensor (under display) Gesture Gyroscope Hall effect Proximity sensor UWB (Ultra Wideband) | Accelerometer Ambient light sensor Barometer Compass Face unlock Fingerprint sensor (under display) Gyroscope Hall effect Proximity sensor |
| Vibrating alert | Supported | Supported |
🔋 Battery | ||
| Galaxy S21 Ultra (SM-G998U1 256GB) | Galaxy S25 (SM-S931B/DS 256GB) | |
| Battery type | LiPo: li-ion polymer (Non removable) | Li-Ion: lithium-ion (Non removable) |
| Battery capacity | 5000 mAh | 4000 mAh |
| Charger, watts | 25W Wired fast charging USB Power Delivery 3.0 | 25W Wired fast charging Reverse charging by cable USB Power Delivery 3.0 |
| Inductive / wireless charging | 15W Qi wireless charging (Qi/PMA) 4.5W Reverse wireless charging | 15W Qi wireless charging 45W Reverse wireless charging |
| Talk time autonomy | feature not registered | feature not registered |
| Standby | feature not registered | feature not registered |
➕ Other features | ||
| Galaxy S21 Ultra (SM-G998U1 256GB) | Galaxy S25 (SM-S931B/DS 256GB) | |
| Call control | Voice dialing, Voice recorder, Voice commands | Voice dialing, Voice recorder, Voice commands |
| Messaging | SMS (T9), MMS, E-mail, Push mail | SMS (T9), MMS, E-mail, Push mail |
| Hands-free calling | Supported | Supported |
| Video calling | Supported | Supported |
| Ringtones | Polyphonic and customized | Polyphonic and customized |
| Web browser | HTML, XHTML, HTML5 | HTML, XHTML, HTML5 |
| Antenna | Internal antenna | Internal antenna |
| Qwerty physical keyboard | Not supported | Not supported |
| Miscellaneous | • Colors: Phantom Black, Silver, Titanium, Navy, Brown • Samsung Pay (Visa, MasterCard) • Samsung DeX • Stylus pen support | • Colors: Blue Black, Icy Blue, Mint, Navy, Silver Shadow, Pink Gold, Coral Red • Samsung DeX • Samsung Wireless DeX |
☢️ Radiation rate | ||
| Galaxy S21 Ultra (SM-G998U1 256GB) | Galaxy S25 (SM-S931B/DS 256GB) | |
| SAR 1.6W/kg (USA, Mexico, etc.) | 0.77W/kg (head), 1.02W/kg (body) | feature not registered |
| SAR 2W/kg (Europe, UK, etc.) | feature not registered | 1.294W/kg (head), 1.363W/kg (body) |