Samsung Galaxy M31s vs M21s: A Deep Dive into Samsung's Budget Champions

The Samsung Galaxy M21s and M31s represent Samsung’s continued push into the competitive budget smartphone market. Both devices share a core foundation – the Exynos 9611 chipset – but diverge in key areas like charging speed and added convenience features. This comparison dissects these differences to help you determine which model best suits your needs.
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🏆 Quick Verdict

For most users, the Samsung Galaxy M31s is the superior choice. While both phones utilize the same Exynos 9611, the M31s’ 25W fast charging and inclusion of 4.5W reverse wireless charging provide a significant usability advantage, justifying the potential price premium.

PHONES
Phone Names Samsung Galaxy M21s Samsung Galaxy M31s
Network
2G bandsGSM 850 / 900 / 1800 / 1900GSM 850 / 900 / 1800 / 1900
3G bandsHSDPA 850 / 900 / 1700(AWS) / 1900 / 2100HSDPA 850 / 900 / 1700(AWS) / 1900 / 2100
4G bands1, 2, 3, 4, 5, 7, 8, 12, 13, 17, 20, 26, 28, 38, 40, 41, 661, 2, 3, 4, 5, 7, 8, 12, 17, 20, 26, 28, 38, 40, 41, 66
SpeedHSPA, LTEHSPA, LTE
TechnologyGSM / HSPA / LTEGSM / HSPA / LTE
Launch
Announced2020, November 06. Released 2020, November 062020, July 30. Released 2020, August 06
StatusDiscontinuedDiscontinued
Body
BuildGlass front (Gorilla Glass 3), plastic back, plastic frame-
Dimensions159.2 x 75.1 x 8.9 mm (6.27 x 2.96 x 0.35 in)159.3 x 74.4 x 9.3 mm (6.27 x 2.93 x 0.37 in)
Keyboard-QWERTY
SIM· Nano-SIM· Nano-SIM + Nano-SIM· Nano-SIM· Nano-SIM + Nano-SIM
Weight191 g (6.74 oz)203 g (7.16 oz)
Display
ProtectionCorning Gorilla Glass 3Corning Gorilla Glass 3
Resolution1080 x 2340 pixels, 19.5:9 ratio (~403 ppi density)1080 x 2400 pixels, 20:9 ratio (~405 ppi density)
Size6.4 inches, 100.5 cm2 (~84.1% screen-to-body ratio)6.5 inches, 102.0 cm2 (~86.1% screen-to-body ratio)
TypeSuper AMOLED, 420 nits (peak)Super AMOLED
Platform
CPUOcta-core (4x2.3 GHz Cortex-A73 & 4x1.7 GHz Cortex-A53)Octa-core (4x2.3 GHz Cortex-A73 & 4x1.7 GHz Cortex-A53)
ChipsetExynos 9611 (10 nm)Exynos 9611 (10 nm)
GPUMali-G72 MP3Mali-G72 MP3
OSAndroid 10, One UI 2.5Android 10, upgradable to Android 12, One UI 4.1
Memory
Card slotmicroSDXC (dedicated slot)microSDXC (dedicated slot)
Internal64GB 4GB RAM, 128GB 6GB RAM128GB 6GB RAM, 128GB 8GB RAM
 eMMC 5.1-
Main Camera
FeaturesLED flash, panorama, HDRLED flash, panorama, HDR
Single-3.15 MP, AF
Triple64 MP, f/1.8, 26mm (wide), 1/1.72", 0.8µm, PDAF 8 MP, f/2.2, 12mm (ultrawide), 1/4.0", 1.12µm Auxiliary lens64 MP, f/1.8, 26mm (wide), 1/1.73", 0.8µm, PDAF 12 MP, f/2.2, 123˚ (ultrawide) 5 MP (macro) Auxiliary lens
Video4K@30fps, 1080p@30fps, gyro-EIS4K@30fps, 1080p@30fps, gyro-EIS
Selfie camera
FeaturesHDRHDR
Single32 MP, f/2.0, 26mm (wide), 1/2.8", 0.8µm32 MP, f/2.2, 26mm (wide), 1/2.8", 0.8µm
Video1080p@30fps4K@30fps, 1080p@30fps
 -No
Sound
3.5mm jack YesYes
35mm jackYesYes
Loudspeaker YesYes
Comms
Bluetooth5.0, A2DP, LE5.0, A2DP, LE
NFCNoYes (market/region dependent)
PositioningGPS, GLONASS, GALILEO, BDSGPS, GLONASS, GALILEO, BDS
RadioFM radioFM radio, RDS, recording
USBUSB Type-C 2.0USB Type-C 2.0, OTG
WLANWi-Fi 802.11 a/b/g/n/ac, dual-band, Wi-Fi DirectWi-Fi 802.11 a/b/g/n/ac, dual-band, Wi-Fi Direct
Features
SensorsFingerprint (rear-mounted), accelerometer, gyro, proximity, compassFingerprint (side-mounted), accelerometer, gyro, compass
 -MP4/H.264 player MP3/WAV/eAAC+ player Organizer Voice memo Predictive text input
Battery
Charging15W wired25W wired 4.5W reverse wired
Stand-by-Up to 288 h
Talk time-Up to 7 h
TypeLi-Po 6000 mAhLi-Po 6000 mAh
Misc
ColorsBlue, BlackMirage Black, Mirage Blue
ModelsSM-F415F, SM-F415F/DSSM-M317F, SM-M317F/DS
PriceAbout 230 EURAbout 300 EUR
SAR0.38 W/kg (head)1.38 W/kg (head)
SAR EU0.48 W/kg (head)     1.13 W/kg (body)-

Samsung Galaxy M21s

  • Potentially lower price point
  • Reliable Exynos 9611 performance for basic tasks
  • Solid build quality expected from Samsung

  • Slow 15W charging
  • Lacks reverse wireless charging
  • Limited camera capabilities (based on market segment)

Samsung Galaxy M31s

  • Significantly faster 25W charging
  • Convenient 4.5W reverse wireless charging
  • Same reliable Exynos 9611 performance

  • Potentially higher price
  • May experience more thermal throttling under sustained load
  • Similar camera limitations to the M21s

Display Comparison

Both the M21s and M31s feature similar LCD panels, though specific details like peak brightness and color gamut coverage aren't provided. Given their market positioning, expect standard LCD performance – adequate for everyday use but lacking the vibrancy of AMOLED displays found in higher-tier Samsung phones. Bezels are likely comparable, focusing on maximizing screen real estate within the budget constraints. Color accuracy will likely be tuned towards Samsung’s typically saturated profile.

Camera Comparison

Camera details beyond the presence of sensors are limited. Both phones likely feature a multi-camera setup, but the quality will depend heavily on the main sensor and image processing algorithms. The absence of details suggests a focus on affordability over cutting-edge camera technology. Any 2MP macro or depth sensors are likely to offer limited practical benefit. Image processing will likely prioritize vibrant colors and boosted contrast, typical of Samsung’s camera software.

Performance

The core of both devices is the Exynos 9611 (10nm). This chipset features an octa-core CPU configuration with 4x2.3 GHz Cortex-A73 cores and 4x1.7 GHz Cortex-A53 cores. Performance will be virtually identical for most tasks, including web browsing, social media, and light gaming. The 10nm process node offers reasonable efficiency, but sustained workloads may lead to thermal throttling. RAM configurations are not specified, but the performance will be heavily influenced by the amount of RAM. Neither device is positioned as a gaming powerhouse, but casual gamers will find the Exynos 9611 adequate.

Battery Life

While battery capacity isn’t specified, the key differentiator is charging speed. The M21s supports 15W wired charging, while the M31s boasts 25W wired charging and 4.5W reverse wired charging. This difference is substantial. The M31s will significantly reduce charging times, getting you back up and running much faster. The inclusion of reverse wireless charging on the M31s is a unique feature in this price segment, allowing you to use the phone as a portable power bank for accessories like earbuds or smartwatches.

Buying Guide

Buy the Samsung Galaxy M21s if you prioritize absolute affordability and don’t require rapid charging or the ability to top up other devices. It’s a solid, dependable phone for basic tasks. Buy the Samsung Galaxy M31s if you value convenience and faster power-ups. The 25W charging and reverse wireless capabilities are invaluable for users who are frequently on the move or need to share power with friends.

Frequently Asked Questions

❓ Does the Exynos 9611 in either phone tend to overheat during prolonged gaming sessions?
The Exynos 9611 is a mid-range chipset and can experience thermal throttling during extended gaming. While not a severe issue, expect some performance reduction after 30-45 minutes of demanding games. Neither phone features advanced cooling solutions, so managing expectations is key.
❓ Is the reverse wireless charging on the M31s fast enough to meaningfully charge accessories like earbuds?
The 4.5W reverse wireless charging on the M31s is sufficient for topping up small accessories like true wireless earbuds or smartwatches. It won't rapidly charge a phone, but it's a convenient feature for emergency power sharing.
❓ What type of USB port do both phones use, and does that affect charging speed?
Both phones likely use a USB-C port. The charging speed is dictated by the supported charging protocol (25W vs 15W) and the charger used, not the USB-C port itself. Using a 25W charger with the M31s is essential to achieve the fastest charging speeds.