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Realme C21

Realme C21 64GB deals

The Realme C21 is in our catalog but no UK retailer currently stocks it.

Spec scores Under £200 Phones · 140 phones
Performance 1.1 /5
Display 1.7 /5
Rear Camera 1 /5
Front Camera 1.5 /5
Battery 2.5 /5
View full breakdown

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 64GB

No 64GB deals available

No UK retailers currently stock the Realme C21 in 64GB.

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 Not available 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.
Compare realme 8 deals

Realme C21 Specifications

Spec Scores

Under £200 Phones · 140 phones

  • Helio G35
  • Octa-core (4x2.3 GHz Cortex-A53 & 4x1.8 GHz Cortex-A53)
140 phones in this group →
This phone
22%
Avg
28%
Best
48%
647 phones in catalog →
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
140 phones in this group →
This phone
34%
Avg
45%
Best
79%
647 phones in catalog →
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
140 phones in this group →
This phone
19%
Avg
30%
Best
49%
647 phones in catalog →
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
140 phones in this group →
This phone
29%
Avg
39%
Best
92%
647 phones in catalog →
This phone
29%
Avg
55%
Best
92%

Based on selfie megapixels and max selfie-video resolution.

  • 5,000 mAh
  • 10W wired
140 phones in this group →
This phone
49%
Avg
49%
Best
72%
647 phones in catalog →
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

Cross Black, Cross Blue

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

32GB 3GB RAM, 64GB 4GB RAM

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