Realme C21 Deals - August 2026
Buy the Realme C21 SIM-free from £189.00 at Back Market.
1 refurbished deal available - SIM-free from £189.00.
Realme C21 SIM Free deals
Find the best SIM Free deal on the Realme C21 from 1 options.
Spec scores
Under £200 Phones · 128 phones
Performance
1.1
/5
Display
1.7
/5
Rear Camera
1
/5
Front Camera
1.5
/5
Battery
2.5
/5
Deals
SIM Free from £189.00
Color
All
Black
Storage
All
64GB
Budget buyers, first-time phone owners and anyone wanting a cheap spare handset where battery life and expandable storage matter more than screen sharpness or camera quality.
Realme C21 SIM Free (1 deals)
Filters
Grade B
C21 64GB (Black)
Cost breakdown
Cashback:
£0.00
Upfront Cost:
£189.00
About the Realme C21
The realme C21 is an entry-level phone built around one clear idea: get through the day, and then some. The 5,000mAh battery is the headline, and paired with a low-power 720p screen and the modest Helio G35 chip it stretches to two days for light users, which is more than most expensive phones manage. realme also gave it a textured, grippy back that hides fingerprints better than the glossy plastic normally used at this end of the market. Expectations need setting, though. The 6.5-inch LCD is HD rather than Full HD, so text and video look noticeably softer than on pricier phones, charging is limited to 10W over an older micro-USB port rather than USB-C, and the 13MP camera is fine outdoors but grainy indoors. It is a 4G phone with no 5G support. What you do get for the money is the practical stuff budget buyers actually use: a 3.5mm headphone jack, a microSD slot for expanding the 32GB or 64GB of storage, dual SIM support and a rear fingerprint sensor. It suits a first phone, a spare, or anyone who values endurance over speed.
Price History
Tracking the best prices since 27 Apr 2026.
SIM-Free (Refurb)
Lowest price in 30 days (£189)
realme C21 vs realme 8 - Key Differences
| Feature | Realme C21 | realme 8 |
|---|---|---|
| Display | 6.5-inch IPS LCD, 720 x 1600, 60Hz | 6.4-inch Super AMOLED, 1080 x 2400, 60Hz |
| Chipset | MediaTek Helio G35 | MediaTek Helio G95 |
| Camera | 13MP main, 2MP macro, 2MP depth, 5MP front | 64MP main, 16MP front |
| Battery and charging | 5,000mAh, 10W charging | 5,000mAh, 30W Dart charging |
| Memory | 3GB or 4GB RAM, 32GB or 64GB storage, microSD | 4GB to 8GB RAM, 64GB or 128GB storage, microSD |
| Weight | 190 g | 177 g |
| SIM-free price | From £189.00 | From £180.00 |
Frequently asked questions
Is the realme C21 worth buying?
It is worth buying if your priority is battery life and low cost rather than performance. The 5,000mAh battery, microSD slot and headphone jack cover the basics well. Anyone who takes a lot of photos, plays games or wants 5G should look at a higher tier, because the HD screen, Helio G35 chip and 10W micro-USB charging all show their limits.
How long does the realme C21 battery last?
The 5,000mAh battery routinely lasts a full day of normal use and can stretch towards two days for light users, helped by the low-resolution screen and efficient Helio G35 chip. The trade-off is charging: it tops up at 10W, so a full charge takes a couple of hours.
Does the realme C21 support 5G?
No. The realme C21 is a 4G LTE phone, so it connects to UK 4G networks only. At this price 4G is the norm, and it makes little practical difference for calls, messaging and streaming.
Can you add a memory card to the realme C21?
Yes. It comes with 32GB or 64GB of storage and takes a microSD card of up to 256GB, which is useful because the built-in storage fills quickly once you add apps and photos. It also has a dedicated 3.5mm headphone jack.
Is the realme C21 camera any good?
The 13MP main camera takes acceptable photos in daylight but becomes grainy indoors and at night. The 2MP macro and 2MP depth sensors add little in practice, and the 5MP front camera is basic. Treat it as a phone for occasional snaps rather than photography.
Should I get the realme C21 or the realme 8?
The realme 8 is a significant step up, with a 6.4-inch Full HD Super AMOLED screen instead of an HD LCD, a much faster Helio G95 chip, a 64MP main camera and 30W Dart charging over USB-C. Both have 5,000mAh batteries. Choose the C21 only if you want the lowest outlay and long battery life, and the realme 8 if screen quality, photos or speed matter at all.
Realme C21 Specifications
Spec Scores
Under £200 Phones · 128 phones
- Helio G35
- Octa-core (4x2.3 GHz Cortex-A53 & 4x1.8 GHz Cortex-A53)
This phone
22%
Avg
28%
Best
45%
This phone
22%
Avg
49%
Best
100%
Based on calibrated CPU benchmark rankings (60%) and GFXBench GPU scores (40%). Apple chipsets included via editorial calibration since AnTuTu under-represents Apple's architecture.
- 6.5 inches
- 720 x 1600 pixels
- IPS, 400 nits peak
This phone
34%
Avg
45%
Best
79%
This phone
34%
Avg
61%
Best
98%
Based on panel type (LTPO is the modern flagship gold standard), resolution, refresh rate, peak brightness, screen size, and HDR10+ / Dolby Vision support. Marketing peak-brightness claims are capped at 3500 nits to prevent inflation.
- Single camera setup
- 13 MP main camera
- 1080p video recording
This phone
19%
Avg
30%
Best
49%
This phone
19%
Avg
41%
Best
98%
Based on main-sensor size (1-inch / 1/1.3" beats 1/2.0"), telephoto reach (periscope > 5x > 3x optical), image processing tier (Apple Pro, Pixel Pro, Galaxy Ultra, Honor Magic Pro, Xiaomi Ultra), pro video features (ProRes, Apple Log, Dolby Vision), camera-partnership branding (Leica, Hasselblad, Zeiss) and OIS. Older flagships are de-rated since image processing pipelines have advanced significantly each generation. Megapixel count is deliberately downweighted — it correlates poorly with real-world camera quality.
- 5 MP front camera
- 1080p selfie video
This phone
29%
Avg
39%
Best
92%
This phone
29%
Avg
55%
Best
92%
Based on selfie megapixels and max selfie-video resolution.
- 5,000 mAh
- 10W wired
This phone
49%
Avg
49%
Best
67%
This phone
49%
Avg
52%
Best
100%
Based on battery capacity (mAh) adjusted for platform efficiency calibrated against NotebookCheck, Tom's Guide, GSMArena and CNET reviewer tests. Apple A-series gets +45% (iOS process freezing + LTPO 1Hz + tuned panels make iPhone Pro Max outlast many 6500+ mAh Android phones in measured tests). Top Snapdragon / Dimensity flagships get +15%, budget chipsets are penalised −15% to −25% to reflect less efficient displays and looser background limits. Charging speed is excluded — see the separate Fast charging tag for that.
General
Dimensions
165.2 x 76.4 x 8.9
Weight
190 g
SIM
Nano-SIM + Nano-SIM
Operating System
Android 10, Realme UI
Colours
Radio
FM radio
Body
Cross Black, Cross Blue
Camera
Primary Camera Megapixels
13
Primary Camera Video
1080@30fs
Second Camera
13 , f/2.2, 26mm (wide), 1/3.06", 1.12µm, PDAF 2 (macro) Auxiliary lens
Selfie Camera Features
HDR, panorama
Primary Selfie Camera
5 , f/2.2, (wide), 1/5.0", 1.12µm
Video Resolution
1080
Selfie Video Resolution
1080@30fs
Display
Type
IPS LCD, 400 nits (typ)
Display Size
6.5
Display Resolution
720 x 1600 pixels, 20:9 ratio (~270 ppi density)
CPU & Memory
Chipset
Helio G35
GPU
PowerVR GE8320
CPU
Octa-core (4x2.3 GHz Cortex-A53 & 4x1.8 GHz Cortex-A53)
Memory Card Slot
microSDXC (dedicated slot)
Internal Storage
Sound
Loudspeaker
Yes
3.5mm Jack
Yes
Connectivity & Data
2G
GSM 850 / 900 / 1800 / 1900
3G
HSDPA 850 / 900 / 2100
4G
1, 3, 5, 7, 8, 20, 28, 38, 40, 41 - International
Network Speed
HSPA, LTE
Network Technology
GSM / HSPA / LTE
Wi-Fi
Wi-Fi 802.11 b/g/n
Bluetooth
5.0, A2DP, LE
USB
microUSB 2.0, OTG
NFC
No
GPS
GPS, GLONASS, BDS
Battery
Battery
5000
Charging
10W wired Reverse wired
Other
Sensors
Fingerprint (rear-mounted), accelerometer, proximity, compass