Samsung Galaxy S21 vs Samsung Galaxy A51 5G (SM-A516U)
Side by side comparison between Samsung Galaxy S21 vs Samsung Galaxy A51 5G phones, differences, pros, cons and full specifications. What's the better?
,
6.2"
AMOLED
AMOLED
1080x2400
12.2
MP
MP
10mp
8GB
RAM
RAM
Octa-core
4000
mAh
mAh
(Non removable)
vs
6.5"
AMOLED
AMOLED
1080x2400
48
MP
MP
32mp
6GB
RAM
RAM
Octa-core
4500
mAh
mAh
(Non removable)
What's the better phone? Samsung Galaxy S21
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!
25 Advantages 
6 Advantages | 25 Common items in both devices |
| 128GB (104GB available) / 128GB (105GB available) |
| Aluminum body, glass front, plastic back |
| Dynamic AMOLED / Super AMOLED |
| 16 million |
| 1080x2400 pixels |
| LED flash |
| PDAF: phase detection autofocus on both cameras / PDAF: phase detection autofocus |
| +18 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 | Galaxy A51 5G (SM-A516U) | |
| Change model | ||
| Model | Galaxy S21 | Galaxy A51 5G (SM-A516U) |
| Other model names | Galaxy S21 5G SM-G991B/DS | Galaxy A51 SM-A516UZKAXAA (Unlocked) |
| Country or region available |  (Global, International) |  USA |
| Brand | Samsung | Samsung |
| Release date | 1/29/2021, Announced: 1/14/2021 | 4/29/2020, Announced: 4/8/2020 |
| Depth | 7.9 millimeters (0.31 inches) | 8.7 millimeters (0.34 inches) |
| Size (width x height) | 71.2 x 151.7 millimeters (2.8 x 5.97 in) | 73.6 x 158.9 millimeters (2.9 x 6.26 in) |
| Weight | 169 grams (5.92 ounces) | 187 grams (6.55 ounces) |
| Build, materials | Aluminum body, glass front, plastic back | Aluminum body, glass front, plastic back |
| Protection against water and others | IP68 certified: water-resistant up to 1.5 meters for 30min and dust-resistant | Not supported |
📲 Display | ||
| Galaxy S21 | Galaxy A51 5G (SM-A516U) | |
| Display type | Dynamic AMOLED | Super AMOLED |
| Screen size | 6.2" inches | 6.5" inches |
| Screen-to-body ratio | ~85.9% (screen-to-body ratio) | ~87.2% (screen-to-body ratio) |
| Display resolution | 1080x2400 pixels (20:9) | 1080x2400 pixels (20:9) |
| Touchscreen | Capacitive Multitouch 10-points | Capacitive Multitouch |
| Pixel density (dot pitch) | 424 PPI | 405 PPI |
| Colors | 16 million | 16 million |
| Scratch-resistant glass | Gorilla Glass Victus | Gorilla Glass 3 |
| Refresh rate | 120Hz | 60Hz |
| Display features | 1300nits[peak] HDR10+ Always-On Display | Always-On Display |
🤖 Operating System | ||
| Galaxy S21 | Galaxy A51 5G (SM-A516U) | |
| System version | Android 11 | Android 10 |
| Firmware update | Android 14 | Android 13 |
| User Interface | One UI 3.1 / 4.1 / 5.1 / 6.0 | One UI 2.5 / 3.1 / 4.1 / 5.0 |
⚙️ Processor | ||
| Galaxy S21 | Galaxy A51 5G (SM-A516U) | |
| Chipset | 64bit: Samsung Exynos 2100 (5nm) | 64bit: Samsung Exynos 980 (8nm) |
| CPU | Octa-core, 3 processors: 1x 2.9GHz ARM Cortex-X1 (Single-core) 3x 2.8GHz ARM Cortex-A78 (Triple-core) 4x 2.2GHz ARM Cortex-A55 (Quad-core) | Octa-core, 2 processors: 2x 2.2GHz ARM Cortex-A77 (Dual-core) 6x 1.8GHz ARM Cortex-A55 (Hexa-core) |
| GPU graphical controller | ARM Mali-G78 MP14 (854MHz) | ARM Mali-G76 MP5 (728MHz) |
| Performance (benchmark) | feature not registered | AnTuTu: 316007 (v8) Geekbench: 1867(v5.1) GFXBench: 17fps (ES 3.1 onscreen) |
💽 Memory and storage | ||
| Galaxy S21 | Galaxy A51 5G (SM-A516U) | |
| RAM memory | 8GB LPDDR5 | 6GB LPDDR4X |
| Internal storage | 128GB (104GB available) UFS 3.1 | 128GB (105GB available) UFS 2.1 |
| External storage | Not supported | Until 1TB microSD, microSDXC (dedicated slot) |
📶 Mobile networks | ||
| Galaxy S21 | Galaxy A51 5G (SM-A516U) | |
| Dual-SIM | Dual-SIM Standby - Call active on one sim card | Not supported |
| SIM card | 2 slots (Dual-SIM) nano-SIM (4FF) + e-SIM | 1 slot (Single-SIM) nano-SIM (4FF) |
| Maximum Download / Upload | 5000/1920 Mbps | 2000/200 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 | GSM 850/900/1800/1900 |
| Primary 3G network | CDMA2000 1xEV-DO TD-SCDMA 1900/2000 UMTS 850/900/1700/1900/2100 | UMTS 850/900/1700/1900/2100 |
| Primary 4G network | LTE Cat24 () TD-LTE () VoLTE | LTE Cat12/13 (1, 2, 3, 4, 5, 7, 8, 12, 13, 17, 20, 26, 28, 66) TD-LTE (38, 40, 41) VoLTE |
| Primary 5G network | SA/NSA/Sub6 () | SA/NSA/Sub6 (41, 78) |
| Primary data network | 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 | GPRS, EDGE, UMTS, HSDPA, HSUPA, HSPA+, TD-LTE, LTE, LTE-A, SA/NSA |
| Secondary 2G network | GSM 850/900/1800/1900 | Not supported |
| Secondary 3G network | UMTS 850/900/1700/1900/2100 | Not supported |
| Secondary 4G network | LTE Cat24 () TD-LTE () VoLTE | Not supported |
| Secondary data network | GPRS, EDGE, UMTS, HSDPA, HSUPA, HSPA+, TD-LTE, LTE, LTE-A | Not supported |
📷 Camera | ||
| Galaxy S21 | Galaxy A51 5G (SM-A516U) | |
| Back camera (main camera) | (triple camera) 12.2 megapixels 64MP telephoto f/2.029mm1/1.72"0.8µmPDAFOIS1.1x-optical-zoom3x-hybrid-zoom 12MP ultrawide f/2.213mm120°1/2.55"1.4µmSuper-Steady-video | (quad camera) 48 megapixels 12MP ultrawide f/2.213mm1.12µm 5MP telephoto f/2.440mm 5MP depth f/2.21/5.0"1.12µm |
| Main camera resolution | 4032x3024 pixels | 8000x6000 pixels |
| Video recording (primary) | 8K UHD (7680x4320) 24 fps | 4K UHD (3840x2160) 30 fps |
| Flash | LED flash | LED flash |
| Focal aperture | f/1.8 (aperture) | f/2.0 (aperture) |
| Focal length | 26mm lens | 26mm lens |
| Sensor size | 1/1.76" inches | 1/2" inches |
| Pixel size | 1.8µm pixel | 0.8µm pixel |
| Autofocus | PDAF: phase detection autofocus on both cameras | PDAF: phase detection autofocus |
| Touch focus | Supported | Supported |
| Image stabilization | OIS: Optical stabilization | EIS: Digital stabilization |
| Zoom | Digital and optical zoom | Only digital zoom |
| Face/smile detection | Face detection, Smile detection | Face detection, Smile detection |
| BSI sensor | Supported | Not supported |
| HDR | HDR photo/video on both cameras | HDR photo on both cameras |
| Camera extras | 4K@60fps 1080p@240fps 720p@960fps | feature not registered |
📸 Front camera | ||
| Galaxy S21 | Galaxy A51 5G (SM-A516U) | |
| Front camera (secondary) | 10 megapixels | 32 megapixels |
| Front camera resolution | 3872x2592 pixels | 6528x4896 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 | 1/3.24" inches | 1/2.8" inches |
| Pixel size | 1.22µm pixel | 0.8µm pixel |
🔉 Sound and multimedia | ||
| Galaxy S21 | Galaxy A51 5G (SM-A516U) | |
| Loudspeaker | Stereo sound 32-bit/384kHz Dolby Atmos Tuned by AKG | Supported |
| Active noise cancellation | 2 microphones or more | 2 microphones or more |
| Radio | FM | FM (RDS) |
| 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 | Galaxy A51 5G (SM-A516U) | |
| USB | USB 3.2 Type-C, USB OTG On-The-Go | USB 2.0 Type-C, USB OTG On-The-Go |
| Audio output | Type-C reversible connector | 3.5mm jack |
| TV output | USB Type-C (reversible) | Not supported |
| Bluetooth | 5.0 + A2DP/LE | 5.0 + 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 [wifi5] (2.4GHz, 5GHz) + MIMO WiFi Direct, hotspot |
| DLNA | Supported | Not supported |
| GPS | A-GPS, GeoTagging, GLONASS, GALILEO, BeiDou | A-GPS, GeoTagging, GLONASS, GALILEO, BeiDou |
| NFC | Supported | Supported |
| Infrared port | Not supported | Not supported |
🧭 Sensors | ||
| Galaxy S21 | Galaxy A51 5G (SM-A516U) | |
| Sensors | Accelerometer Ambient light sensor Barometer Compass Face unlock Fingerprint sensor (under display) Gesture Gyroscope Hall effect Proximity sensor | Accelerometer Ambient light sensor ANT+ Compass Face unlock Fingerprint sensor (under display) Gyroscope Hall effect Virtual proximity sensor |
| Vibrating alert | Supported | Supported |
🔋 Battery | ||
| Galaxy S21 | Galaxy A51 5G (SM-A516U) | |
| Battery type | LiPo: li-ion polymer (Non removable) | LiPo: li-ion polymer (Non removable) |
| Battery capacity | 4000 mAh | 4500 mAh |
| Charger, watts | 25W Wired fast charging USB Power Delivery 3.0 | 15W Wired fast charging |
| Inductive / wireless charging | 15W Qi wireless charging (Qi/PMA) 4.5W Reverse wireless charging | Not supported |
| Talk time autonomy | feature not registered | feature not registered |
| Standby | feature not registered | feature not registered |
➕ Other features | ||
| Galaxy S21 | Galaxy A51 5G (SM-A516U) | |
| Call control | Voice dialing, Voice recorder, Voice commands | Voice dialing, Voice recorder |
| 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 Gray, White, Violet, Pink • Samsung Pay (Visa, MasterCard) • Samsung DeX | • Colors: Prism Cube Black, Prism Cube White, Prism Cube Pink |
☢️ Radiation rate | ||
| Galaxy S21 | Galaxy A51 5G (SM-A516U) | |
| SAR 1.6W/kg (USA, Mexico, etc.) | feature not registered | 1.18W/kg (head), 1.2W/kg (body) |
| SAR 2W/kg (Europe, UK, etc.) | 0.456W/kg (head), 1.509W/kg (body) | feature not registered |