Karbonn has been making news recently with its dual-core Android-based smartphones and the A21 is the latest entrant in its Android smartphone line-up. The recent advertisements state that the phone can do two jobs at a single given time, which is true to quite an extent given that it is equipped with a dual-core processor. Well, let's find out if the phone is really smart enough.

4.5-inch display, Android ICS OS.

4.5-inch display, Android ICS OS

Design and build

The A21 from Karbonn has a great design and an aesthetically appealing exterior. The dual-tone black and white body makes it look a class apart and trust us, it does not feel like any of the cheap phones. Though the handset looks classy, the chassis is made from a strong and durable plastic with a semi-matte and glossy finish. It can get pretty ugly looking after a bad fall or if it is not properly handled. The edges especially are glossy and the white rear panel can get smudged with dirty hands pretty fast. The front panel features four capacitive buttons for Home, Menu, Back and Search along with a large 4.5-inch LCD display. Towards the top is the earpiece and a front camera, and next to it is a translucent window that hides the proximity and light sensors. The rear panel sports a camera and an LED flash towards the top and a speaker grill on the bottom. The volume rocker is placed on the right while the power and audio jack are seen on the top. The right side has the micro USB interface. Overall, the design looks impressive and does sport a good look for a phone priced in the the Rs 10,000 bracket (approximate price in the local market). Lastly, the rear panel opens up to the battery compartment where you can see the two SIM slots and a hot-swappable microSD card bay. 

5 MP rear camera with single LED flash.

5 MP rear camera with single LED flash

Features and performance 

The A21 from Karbonn’s Duple series of smartphones features a dual-core Qualcomm Snapdragon processor clocked at 1.2GHz. As per our benchmarking utilities, we found the processor running on a maximum 1.15GHz—so either the processor is underclocked for stability or the speed of the processor is rounded-off to 1.2GHz for the spec sheet. Coupled with the processor is an Adreno 203 graphics processor and 512MB of RAM. Here again, as per the benchmarking apps, the information passed out about the RAM is that 386MB is in use by the operating system itself and the rest is available for user apps. This amount of memory does not feel sufficient enough for a dual-core based hardware but is good enough for casual and basic operations. The internal storage provided is 4GB, which can be extended using a microSD card. The display is a large 4.5-inch LCD with a resolution of 480 x 800, but all our tests reveal a resolution of 540 x 960 pixels. A 5MP camera with an LED flash is provided on the rear and a 1.3MP camera for video calling is available on the front panel. 

Dual tone black and white body with glossy front and back panels

Dual-tone black and white body with glossy front and back panels

The A21 features dual SIM support, of which one is capable of 3G while the other is 2G. So you have an option of using one SIM for the Internet channel while the other can be used for voice calls. The Internet can also be connected using the Wi-Fi b/g/n interface. Other connectivity options are Bluetooth and a micro USB PC interface. A-GPS onboard can be used for your navigation purposes. Lastly, a 1800 mAh battery completes the phone’s specification section.

Volume rocker on the right side

Volume rocker on the right side

Power and audio jack on the top

Power and audio jack on the top

On the performance front, we did find the phone faster than most single-core processor based Android phone in the market. However, after using it for a while with a few apps and games, we did find it getting a bit sluggish thanks to the insufficient memory provided for the user apps, which runs out in no time if you use memory-heavy apps including a live-wallpaper. Casual free games downloaded from the Play store would suffice, but keep away from high-definition and GPU heavy games as they could get sluggish in no time and you will lose out on battery life in no time. 

1800 mAh battery, hot-swapable microSD card, DUAL SIM GSM

1800 mAh battery, hot-swapable microSD card, dual SIM GSM

Benchmark tests using AnTuTu, Quadrant, NenMark2 and Linpack were also done. AnTuTu scored 6566, Quadrant scored 1827 and NenaMark2 gave us a frame rate of 27.8 fps. Linpack resulted in 44.28 MFLOPs and 66.85 MFLOPS in single-thread and multi-thread tests respectively. Analyzing the scores with a similar hardware-powered handset revealed the scores of the A21 was almost 10 percent higher than the rest. Summing up the entire performance, we conclude that the A21, though powered by a dual-core processor, does not perform as anticipated. Hence, don’t expect this phone to perform as high-end phones would. Casual usage and a few apps in multi-tasking would suffice the performance as expected. But this is the least one can expect from a phone in the Rs 10K bracket. If you want sheer performance, you should look at models from different brands. 

Processor clocked at 1.15 GHz, display resolution shows 540 x 960 pixels

Processor clocked at 1.15GHz, display resolution shows 540 x 960 pixels


As stated earlier, the 4.5-inch LCD display sports a resolution of 540 x 960. The quality of the display is excellent with a good balance of brightness, contrast and colours. The display is crisp and clear except for the viewing angle from the top (in portrait mode) or from the left (in landscape mode). The display quality tends to fail to quite an extent especially while watching a movie in landscape mode. You have to keep your eye at flat 90 percent angle from the screen—deflect slightly towards the left and the contrast goes down. Deflect further away and the display turns negative. Viewing from the right has a very little variation and is good enough. So if you are watching a video with friends, make sure they are viewing it from the right side. Apart from this issue, we did not find any other glitches. 

Stock ICS launcher, few freee apps thrown in

Stock ICS launcher, few freee apps thrown in

User interface

The A21 features the Android ICS v4.0.4 operating system, which can be further upgraded over the air (OTA) as and when the manufacturer releases an update. It uses the stock ICS home launcher and a few apps are throws in for free. As mentioned earlier, we did find the UI a bit sluggish—thanks to the low available memory. Use of a memory manager app is a must if you ought to keep the phone running smoothly.  


We did playback a few movies ranging from standard definition ones to full HD flicks. The built-in video player is not good enough to handle HD videos and we did try using MoboPlayer and MX player as an alternative. We found that the phone could handle SD videos without any issues. However, HD videos were a tad jittery while full HD 1080p videos were almost unwatchable. The processor was monitored at the different video playbacks – it was at around 35 percent while playing SD videos and 100 percent while playing 720p and 1080p videos. The videos were not handled by the GPU at all and hence, the playback wasn’t smooth enough. We also witnessed a little heat building up on the rear panel whilst watching movies. Though this may feel normal, it is a sign of a high strain on the processor. 

Audio playback on the device is just as good as any phone can handle, but the bundled earphones are not as one would need. The audio quality of the earphones is below average and just good enough for voice calls. We recommend using a better quality earphone if you want to enjoy music and movies. The onboard speaker is mono and the audio quality and volume levels are just about good enough in close proximity. No complaints here.

The 5 MP rear camera is an average shooter

The 5 MP rear camera is an average shooter


We were not impressed with the capture quality of the 5MP main shooter. Outdoor shoots were decent, but brightly lit areas get overexposed. Low-lit areas or indoor shoots turned out to be a bit like a water-coloured painting while brightly lit areas and outdoor shoots were slightly overexposed in certain areas. Zoom in to any of the photos and you will see the smudges immediately, so don’t expect too much from the rear camera. Looking at the entire image in 100 percent is just about good enough for casual shoots and uploads to social networking sites. We also did find the shooter a tad slow whilst shooting—the image is captured with a delay of about one second after you hit the shutter release button. This makes it difficult to capture the exact moment of the action you desire. The front camera is good enough for video chats when in close proximity. Further away, the pics and videos are no good and worse than a standard VGA camera.

indoor photos are below average with noisy images

Indoor photos are below average with noisy images

Battery life

The battery provided with the handset is a decent 1800 mAh, which will give you a maximum of around 5–6 hours of talk time as per the manufacturer’s specifications and claims. Casual usage of the phone during the day made the battery on our test piece last for about 7 hours, during which we used the phone in the wireless network surfing the Internet, made voice calls, shot a few pictures, played a few games and watched a few video clips. This battery life cannot be considered as an exact value as it would differ because the usage from person to person would vary. 


To end the entire experience with the Karbonn A21, we would state that the phone is definitely better than lower budget single-core Android-based handsets in the market. However, it could do better as it sports a dual-core processor. But the low budget price and the feature set it sports makes it a good value for money. The phone does beat the other ones in the similar segment in terms of sheer performance scores. The MRP of the Karbonn A21 is Rs 11,990, but the unit is available for approximately Rs 9,900 in the local market. On the other hand, there are not many dual-core Android phones with a price tag below the Rs 10,000 price mark, which makes us recommend this phone to those looking for a large screen dual-core handset for cheap. The Superfone Canvas II is an alternative, but this one seems better. 

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