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realme C21 review: Colourful, cheap but just too slow

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realme C21
Finder score
  • Battery Score 3.5
  • Camera Score 3
  • Design Score 3.5
  • Performance Score 3


Quick verdict: The realme C21 has some attractive style and onboard NFC, but it’s otherwise overshadowed by more powerful phones in the budget space.


  • Nice design
  • NFC onboard
  • 5,000mAh battery

  • Slow performance
  • Average cameras
  • microUSB charging

In this guide

  • Review
  • Details
    • Pricing & Availability
  • Ask a question


Pricing & Availability

Launch price (RRP) $0
Launch date 2021-03
realme C21

We've seen a huge number of real budget phones make their way through Finder's labs of late, and in many cases, I've ended up comparing them to one of my favourite budgets handsets of recent years, realme's excellent little realme C3.

The realme C21 could be seen as the next logical extension of realme's pursuit of low-cost buyers. It costs less than $200, comes with multiple cameras and plenty of style that's been realme's trademark to date. However, the budget space is far more competitive than it was when the realme C3 launched, and that makes the realme C21 a harder handset to recommend.



  • Blue or Black plastic finish
  • 6.5-inch 720p display
  • Fingerprint sensor is a little too high up
realme C21

The realme C21 ships in two fairly simple colours that realme describes as "Cross Black" or "Cross Blue". The colours are rather inherent, and they're "Cross" colours presumably due to the diagonal X pattern that forms on the rear of the phone body. However, they're resolutely plastic-body phones, and you're not going to fool anyone that they're made to a premium standard. That's to be expected for a sub-$200 handset from any manufacturer, however.

The realme C21 uses a rear-mounted fingerprint sensor. Ordinarily, this is my preferred solution for ease of access, but in the case of the realme C21, it's very high up the body, which means it's a little harder to easily access than I'd like. Your own digit length and comfort may vary.

At the front, the realme C21 uses a 6.5-inch 1600x720 pixel display with a teardrop style notch that realme refers to as a "mini-drop" screen – not because you should bounce it off the floor, but because of that notch-style choice. It's moderately unobtrusive, and like so many other budget phones, you're stuck with a maximum 720p output for video watching or gaming.

Controls are kept simple with volume and power up the right-hand side and combination SIM and microSD card tray at the right. Unlike some competing budget Android phones we've tested recently, there's no dedicated Google Assistant button if that's important to you.



  • Triple lens with macro and mono
  • Can't shoot with the mono lens
  • Maximum 4x digital zoom
realme C21

In the budget space, we've seen a lot of phones ship with a primary higher megapixel sensor and one of the seemingly endless array of 2MP macro lenses, so it's not some great surprise to see realme opt for that mixture as well. However, alongside its primary 13MP f/2.2 sensor and 2MP f/2.4 macro lens, there's a tertiary monochromatic 2MP f/2.4 sensor as well.

However, my initial excitement at being able to test out a budget phone with a true mono lens was instantly snuffed out, as realme simply uses that third mono lens to provide contrast to the primary and macro lenses, rather than let you shoot with it outright. Admittedly, at 2MP, you wouldn't get stunning shots, but I really do miss the days of actual mono lenses on phones.

Like every other macro lens on a budget phone – and that's essentially every budget phone right now – the realme C21 doesn't impress with picture fidelity when shooting up close. You'll need plenty of patience and luck to get pleasing photos, many of which tend to end up with somewhat oversaturated colours once they've been through realme's AI optimisations.

This once again leaves the primary lens as the one you'll spend most of your time with, and it's simply OK without being particularly notable. The realme C21 doesn't launch its camera software particularly quickly, and you're limited to a scant 4x digital zoom if you do need to get closer to your subject without physical movement.

The issue here is there's no huge jump up from the realme C3. While that was a slightly more expensive phone when it launched, over time, it's reasonable to expect improvement in this space. You can get decent shots from the realme C21, but that's about as far as you can ever go.



  • Helio G35 isn't a fast processor
  • Onboard NFC is a nice plus
  • realme UI struggles
realme C21

The realme C21 is built around MediaTek's Helio G35 platform with 4GB of RAM and 64GB of onboard storage, expandable via microSD. MediaTek remains the processor maker of choice for cheap smartphones because they're highly affordable parts, but they're not often particularly quick. The Helio G35 is a new one through the Finder labs, with many of realme's competitors opting for the Helio G25 instead. On paper, that should give the realme C21 something of an edge over its competitors.

In reality – both in day-to-day usage and synthetic benchmarks – it's a difference that's often hard, if not impossible, to see.

Here's how the realme C21 compares against a range of similarly priced handsets using Geekbench 5's CPU test:

And here's how its IMG PowerVR GE8320 GPU compares using 3DMark's Slingshot Extreme graphics test. Like so many of its competitors, it doesn't quite have the grunt for the newer Wildlife test:

The realme C21 is a little slower than the C3 was, but then that was a phone that originally sold for more than $200. The more striking comparison there is the Motorola Moto G10, a phone that outdoes the C21 by a significant amount. With any synthetic benchmark, there can be room for fudging, not to mention manufacturer juicing, so I then turned to actual app usage, and here again, it became apparent that the realme C21 was just a step behind its contemporaries. Lag was common in most apps, and especially any kind of graphically busy modern game app, where it wasn't uncommon to see dropped frames and long load times.

To an extent, that's to be expected in budget phones, but it's just that little bit worse on the realme C21. The most likely culprit here is realme's launcher, realme UI 1.0, which runs on top of Android 10. The comparably priced Moto G10 has a cleaner Android interface, which means it's got a bit more headroom for apps as a result. If you like the brighter style of realme UI that may be a price you're willing to pay, but I'd rather have a faster, more responsive handset.

One feature that you don't see much on cheaper Android phones that is packed into the realme C21 is NFC. The NFC chip in the realme C21 means that it can be used with payment systems such as Google Pay, making it a handy credit card alternative in its own right.

Battery life

Battery life

  • 5,000mAh battery performs slightly under expectations
  • microUSB charging is disappointing
realme C21

The realme C21 ships with a 5,000mAh battery, which is a pleasing quantity in a sub-$200 handset, although not unique to realme in this space. While that's the general ceiling most makers are putting on their phones for weight, cost and safety reasons right now, it does rather make you wonder how phones that cost multiples of the price point of the C21 justify smaller battery capacities.

That aside, to put the realme C21 to the test, I ran it through Finder's standard comparative battery test, looping a full resolution YouTube video for an hour from a full battery to get a figure on battery drain. As a reminder, while battery usage can be wildly variant, what we look for here is at least 90% battery remaining after an hour as that's a sign of a phone that should have no issue lasting through at least one full day of regular usage.

Here's how the realme C21 compares:

That 92% figure is fine, and a good indicator of a phone that should be able to manage a day easily and even a second one if you're a light user, although again it's worth noting that comparable phones in the same price bracket did ever so slightly better than the realme C21 in this test.

It's also a little disappointing to see realme stick with the older microUSB charging standard for the realme C21 where competitors are finally switching over to USB-C.

Should you buy the realme C21?

  • Buy it if you want a cheap phone and you really like the realme C21’s style.
  • Don't buy it if you want the best phone you can get in the sub-$200 space.

The realme C3 was a revelation in the budget space for value and features, but the realme C21 just doesn't quite reach those heights. There's little that's terribly wrong with it as a phone at this price point, and it's a nice looking device with inbuilt NFC if that's important to you. However, competitors have really stepped up their game since the realme C3 came to market, while it appears that realme was just treading water.

Pricing and availability



Display Size
6.5 inches
1600 x 720px


Rear camera megapixels
13MP + 2MP + 2MP
Rear camera aperture size
f/2.2 + f/2.4 + f/2.4
Video recording
Front camera megapixels
Front camera aperture size

Physical Dimensions

165.2mm x 76.4mm x 8.9mm


802.11 a/b/g/n
Network category speed

Power, storage and battery

Helio G35
Operating system
Android 10
Internal storage
External storage support
Up to 16GB
Battery capacity

Device features

Headphone jack
Fingerprint sensor
Water resistance rating

Images: Alex Kidman

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