Compare phones
| Global Score | |
| 74.6 | 84.1 |
| Basic Information | |
| Samsung | Samsung |
| Android 8.0 Oreo | Android 11, 10 |
| -- | 2020-03-23 |
| 6.04 x 3.04 x 0.32 inches | 6.26 x 2.96 x 0.35 inches |
| 6.14 ounces | 6.63 ounces |
| 16 777 216 | Midnight blue and Raven black |
| Plastic | Plastic and Plastic |
| Scratch-Resistant Glass | Scratch-Resistant Glass |
| Display / Screen | |
| 5.5 inches | 6.4 inches |
| 1280 x 720 pixels (HD) | 2340 x 1080 pixels |
| Super AMOLED | Super AMOLED |
| 267 pixels per inch | 403 pixels per inch |
| -- | 420 cd/m2 brightness |
| No touch screen | No touch screen |
| 7.1 | 8.4 |
| Performance | |
| Samsung Exynos 7 Octa 7884 chipset | Exynos 9611 chipset |
| ARM Cortex-A53, 64-bit, 14 nm (Octa-Core 1600 MHz) processor | Arm Cortex-A73 and Arm Cortex-A53, 64-bit, 10 nm (Octa-Core 2300 MHz) processor |
| 4 GB RAM | 4 GB RAM |
| ARM Mali-G71 GPU | Mali-G72 MP3 GPU |
| 8.82 | 9.27 |
| Storage | |
| 32 GB internal memory | 64 GB internal memory |
| microSDXC (up to 256 GB) external memory slot | microSDXC (up to 512 GB) external memory slot |
| 8.88 | 11.74 |
| Camera | |
| 13.00 MP + 8.00 MP | 48.00 MP + 20.00 MP |
| f/1.90 aperture | f/2.00 aperture |
| 27.00mm focal length | 26.00mm focal length |
| 0.33 inches (1/3.06") sensor | 0.5 inches (1/2") sensor |
| 1920 x 1080 (30 fps) (Full HD) video resolution | 3840 x 2160 (30 fps) (4K) video resolution |
| -- | 1920 x 1080 (240 fps) (Full HD) slow motion video |
| 9.02 | 11.55 |
| Networks | |
| Wi-Fi | Wi-Fi |
| Mobile Hotspot | Mobile Hotspot |
| LTE (4G), HSPA and HSUPA | LTE-A (4G), LTE (4G), HSPA+ (4G), HSDPA and HSUPA |
| Micro SIM, Dual SIM | Nano SIM, Dual SIM |
| 6.1 | 6.7 |
| Battery Life | |
| 3000mAh Battery | 6000mAh Li - Polymer Battery |
| Removable Battery | Non-Removable Battery |
| 4.96 | 7.52 |
| Other Features | |
| Bluetooth 5.0 | Bluetooth 5.0 |
| GPS | GPS |
| Fingerprint ID Scanner | Fingerprint ID Scanner |
| Accelerometer, Light Sensor and Proximity Sensor | Accelerometer, Gyroscope and Proximity Sensor |
| FM Radio | FM Radio |
Comparison review
Samsung Galaxy M21 is much better than the Galaxy J7 Duo, having an 84.1 score against 74.6. Both of these phones have Android OS (operating system), but Samsung Galaxy M21 has an older 11 version and Galaxy J7 Duo has Android 8.0 Oreo version. Even being the best in this comparison review, Samsung Galaxy M21's design is a little thicker and just a bit heavier than Galaxy J7 Duo.
Samsung Galaxy M21 counts with a bit better performance than Samsung Galaxy J7 Duo. Both of them have the same RAM memory amount and a Octa-Core processing unit. The Galaxy M21 counts with a brighter display than Samsung Galaxy J7 Duo, because it has way more pixels per screen inch, a lot higher 1080 x 2340 resolution and a bigger screen.
Galaxy M21 features a much better camera than Galaxy J7 Duo, because although it has a smaller diafragm aperture, it also counts with a way bigger back camera sensor taking much better quality photos and videos, a back camera with lot more mega-pixels and a much better 3840x2160 video resolution. The Samsung Galaxy M21 counts with a much better storage capacity to store more games and applications than Galaxy J7 Duo, because it has 32 GB more internal memory and a SD memory slot that admits a maximum of 512 GB.
The Samsung Galaxy M21 has a very superior battery lifetime than Galaxy J7 Duo, because it has 6000mAh of battery capacity.
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