In depth comparison and review of Microsoft Surface Duo and Realme C21. Compare sizes, cameras, batteries, memory, and other important specifications and features to easily choose the right phone for you. Our goal is to help you uncover differences between the products and find the phone that will best fit your needs.
| DESIGN AND DIMENSIONS | Microsoft Surface Duo | Realme C21 |
|---|
| Product Type | Smartphone | Smartphone | |
|---|---|---|---|
| Form Factor | Folder - dual screen | Touch | |
| Height | 145.2 mm | 165.2 mm | Realme C21 has greater height than Microsoft Surface Duo. |
| Width | 93.3 mm | 76.4 mm | Microsoft Surface Duo has greater width than Realme C21. |
| Depth | 9.9 mm | 8.9 mm | Realme C21 is narrower than Microsoft Surface Duo. |
| Weight | 250 g | 190 g | Realme C21 is lighter than Microsoft Surface Duo. |
| Dimensions Details | Unfolded - 186.9 mm x 4.8 mm x 145.2 mm | - | |
| Body Colour | Glacier | Cross black | Cross blue | |
| Waterproof (Water-resistant) | - | - | |
| SAR Value | 0.726 W/kg (head), 1.478 W/kg (body) | - | |
| Connector Type | USB Type-C - 24 pin USB-C | Micro-USB Headset jack - mini-phone 3.5mm |
|
| SIM Card Type (Size) | Nano SIM, Electronic SIM card (e-SIM) | Nano SIM | |
| SIM Card Qty | Dual-SIM | Dual-SIM |
| DISPLAY | Microsoft Surface Duo | Realme C21 |
|---|
| Display Type | OLED display | LCD display | |
|---|---|---|---|
| Display Technology | AMOLED | LCD | |
| Foldable Display | Yes | - | |
| Display Design | Both directions folding | - | |
| Screen Size (Display Size) | 5.6" | 6.5" | Realme C21 has larger screen size than Microsoft Surface Duo. |
| Screen Resolution (Display Resolution) | 1800 x 1350 pixels | 1600 x 720 pixels | Microsoft Surface Duo has better screen resolution than Realme C21. |
| Display Format | - | HD+ | |
| Pixel Density | 401 ppi | - | |
| Aspect Ratio | 4:3 | 20:9 | |
| Max Brightness | - | 420 cd/m² | |
| Display Features | PixelSense Fusion Displays | Mini-drop display | |
| Display Protection (Screen Protector) | Corning Gorilla Glass (scratch resistant glass) | - |
| SECOND DISPLAY |
|---|
| Second Display Type | OLED display - colour | - | |
|---|---|---|---|
| Second Display Screen Size | 5.6" | - | |
| Second Display Resolution | 1800 x 1350 pixels | - |
| UNFOLDED DISPLAY |
|---|
| Unfolded Display Screen Size | 8.1 in | - | |
|---|---|---|---|
| Unfolded Display Resolution | 2700 x 1800 pixels | - |
| PROCESSOR | Microsoft Surface Duo | Realme C21 |
|---|
| Processor Type (CPU) | Qualcomm Snapdragon 855 | MediaTek Helio G35 | |
|---|---|---|---|
| Clock Speed | - | 2.3 GHz | |
| Processor Core Qty | 8-core | 8-core | Both phones have the same number of phone cores. |
| Graphics System (GPU) | - | PowerVR GE8320 |
| MEMORY | Microsoft Surface Duo | Realme C21 |
|---|
| RAM | 6 GB | LPDDR4X SDRAM - 3 GB | Microsoft Surface Duo has more RAM than Realme C21. |
|---|---|---|---|
| Internal Memory Size (Storage Capacity) | 128 GB | 32 GB | Microsoft Surface Duo has more internal memory than Realme C21. |
| Memory Interface | UFS 3.0 | - | |
| Supported Flash Memory Cards (Expandable Memory) | - | microSD |
| CAMERA | Microsoft Surface Duo | Realme C21 |
|---|
| MAIN CAMERA |
|---|
| Number of Main Cameras | 0 | 3 | |
|---|---|---|---|
| Sensor Resolution | - | 13 Megapixel | |
| Lens Aperture | - | F/2.2 | |
| Lens Construction | - | 5-element | |
| Focus Adjustment | - | Automatic | |
| Digital Zoom | - | 4x | |
| Special Effects | - | HDR | |
| Camera Modes | - | Panorama, Time-lapse mode, Slow motion mode, Beauty mode, Expert Mode, Nightscape capture mode, Portrait, Filter mode, Super nightscape | |
| Light Source | - | LED flash | |
| Video Resolutions | - | 1920 x 1080 (1080p) at 30 fps | |
| Camera Features (Functions) | - | Phase Detect Auto-Focus (PDAF), AI Triple camera, Chroma boost |
| SECOND CAMERA |
|---|
| Sensor Resolution (2nd Camera) | - | 2 Megapixel | |
|---|---|---|---|
| Lens Aperture (2nd Camera) | - | F/2.4 | |
| Lens Element Qty (2nd Camera) | - | 3-element | |
| Camera Functions (2nd Camera) | - | B&W lens |
| THIRD CAMERA |
|---|
| Sensor Resolution (3rd Camera) | - | 2 Megapixel | |
|---|---|---|---|
| Lens Aperture (3rd Camera) | - | F/2.4 | |
| Lens Element Qty (3rd Camera) | - | 3-element | |
| Camera Functions (3rd Camera) | - | Macro camera | |
| Camera Features (3rd Camera) | - | 4cm macro photography |
| FRONT CAMERA |
|---|
| Number of Front Cameras | 1 | 1 | |
|---|---|---|---|
| Sensor Resolution (Front) | 11 Megapixel | 5 Megapixel | Microsoft Surface Duo has better front camera resolution than Realme C21. |
| Lens Aperture (Front) | F/2.0 | F/2.2 | Microsoft Surface Duo has better front lens aperture than Microsoft Surface Duo. |
| Lens Element Qty (Front) | - | 3-element | |
| Field of View (Front) | 84 degree(s) | - | |
| Pixel Size (Front) | 1 μm | - | |
| Special Effects (Front) | HDR | HDR | |
| Camera Modes (Front) | Burst mode, Panorama, low-light shots, Portrait mode with adjustable depth control | Time-lapse mode, Beauty mode, portrait mode, AI Beauty, Filter mode, Panoramic mode | |
| Face Recognition (Face ID) | - | Face recognition | Realme C21 has face detection. |
| Light Source (Front) | High CRI LED flash | - | |
| Video Resolutions (Front) | 1920 x 1080 (1080p) at 30 fps, 1920 x 1080 (1080p) at 60 fps, 3840 x 2160 (4K) at 30 fps, 3840 x 2160 (4K) at 60 fps | - | |
| Camera Features (Front) | Phase Detect Auto-Focus (PDAF), FOV optimised with AI (for front and rear), dynamic range scene detection, Super-resolution zoom, super zoom up to 7x, gyro-based digital video stabilisation | - |
| BATTERY AND CHARGING | Microsoft Surface Duo | Realme C21 |
|---|
| Battery Capacity (Battery Size) | 3577 mAh | 5000 mAh | Realme C21 has larger battery capacity than Microsoft Surface Duo. |
|---|---|---|---|
| Standby Time | 240 hours | - | |
| Talk Time | 1620 minutes | - | |
| Run Time Details | Standby: up to 240 hrs Talk: up to 1620 min Playback (local video): up to 15.5 hrs |
- |
| CELLULAR | Microsoft Surface Duo | Realme C21 |
|---|
| Technology | WCDMA (UMTS) / GSM | WCDMA (UMTS) / GSM | |
|---|---|---|---|
| Mobile Broadband Generation | 4G | 4G | Both phones have the same mobile network generation. |
| Operating System | Android 10 | Android 10 | |
| User Interface | - | Realme UI | |
| Intelligent Assistant | Google Assistant | - | |
| Navigation | GPS, GLONASS, BeiDou, Galileo, QZSS | GPS, A-GPS, GLONASS, BeiDou |
| COMMUNICATIONS | Microsoft Surface Duo | Realme C21 |
|---|
| Data Transmission | GPRS, FDD-LTE, TDD-LTE, LAA | FDD-LTE, TDD-LTE | |
|---|---|---|---|
| 2G Band | 850 GSM, 900 GSM, 1800 GSM, 1900 GSM | 850 GSM, 900 GSM, 1800 GSM, 1900 GSM | |
| 3G UMTS Band | Band 1, Band 2, Band 5, Band 8 | Band 1, Band 5, Band 8 | |
| 3G UMTS Frequency | 2100, 1900, 850, 900 | 2100, 850, 900 | |
| 4G LTE Band | Band 1, Band 2, Band 3, Band 4, Band 5, Band 7, Band 8, Band 12, Band 13, Band 14, Band 19, Band 20, Band 25, Band 26, Band 28, Band 29, Band 30, Band 38, Band 39, Band 40, Band 41, Band 46, Band 66 | Band 1, Band 3, Band 5, Band 7, Band 8, Band 20, Band 28, Band 38, Band 40, Band 41 | |
| 4G LTE Frequency | FDD 2100, FDD 1900 PCS, FDD 1800+, FDD 1700 - 2110 AWS, FDD 850, FDD 2600, FDD 900, FDD 700a, FDD 700c, FDD 700 PS, FDD 800 upper, FDD 800 DD, FDD 1900+, FDD 850+, FDD 700 APT, FDD 700d, FDD 2300 WCS, TDD 2600, TDD 1900, TDD 2300, TDD 2500, TDD 5150, FDD 1700 - 2110 AWS-3 | FDD 2100, FDD 1800+, FDD 850, FDD 2600, FDD 900, FDD 800 DD, FDD 700 APT, TDD 2600, TDD 2300, TDD 2500 | |
| Wireless Interface | IEEE 802.11ac | IEEE 802.11b/g/n | |
| Bluetooth | Bluetooth 5.0 | Bluetooth 5.0 |
| MEDIA | Microsoft Surface Duo | Realme C21 |
|---|
| Supported Digital Audio Standards | WAV, AAC, AMR, MP3, FLAC, OGG, MIDI, M4A, apt-X, IMY, RTTTL, RTX, OTA, MID | - | |
|---|---|---|---|
| Supported Digital Video Standards | MKV, FLV, AVI, MOV, WMV, 3GP, TS, WebM, H.265 HEVC, MP4 | - | |
| Sound Enhancements | Qualcomm aptX audio | - |
| FEATURES | Microsoft Surface Duo | Realme C21 |
|---|
| Phone Functions | Speakerphone, voice control, call timer, conference call, flight mode, voice dialing, vibrating alert | Speakerphone, voice control, call timer, conference call, flight mode, voice dialing, vibrating alert | |
|---|---|---|---|
| Sensors | Proximity sensor, hall sensor, dual accelerometers, dual gyroscope, dual magnetometer, dual ambient light sensor | Accelerometer, proximity sensor, magnetometer, light sensor | |
| Security Devices | Fingerprint reader (side) | Fingerprint reader | |
| Additional Phone Features | MIMO technology, Fast Charging, dual microphones with noise suppression and echo cancellation, Full Duplex communication, 360° hinge, stylus support, two apps side-by-side | Super power saving mode, HyperEngine technology, Reverse charging |
| OTHERS | Microsoft Surface Duo | Realme C21 |
|---|
| Included Accessories | SIM card removal tool, USB-C headphones, 18W charger, Surface Duo Bumper (Glacier) | USB cable, power adapter, SIM card removal tool | |
|---|---|---|---|
| Compliant Standards | - | TUV Rheinland |
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