NokiaXR21

How we test call clarity

We test call quality by calling in both a quiet room and with a simulated noisy environment.

How we test battery

Our phone test simulates a full day’s phone use, including making calls, taking photos, watching videos and navigating through a map app. The best phones last for 30 hours or more, while the worst conk out after just 16 hours. We also check how the battery copes with just a 15 minute charge and how long it takes to reach 100%.

How we test camera

We check how well your pictures and videos come out on both the front and rear lenses, looking at colour accuracy, flash uniformity and the quality of the zoom. We test in 10 different shooting environments to make sure the cameras are consistent and use mannequins with different skin tones.

How we test ease of use

This covers a range of tests from how well the menu is laid out to how easy it is to unlock the phone and the sensitivity of the touchscreen, so you won’t be left with a phone that’s frustrating to use.

How we test display

You want a phone with a vivid, detailed and easily readable display, so we check how the screen looks in different light conditions and use microscopes to asses sharpness and resolution.

How we test speed

Our speed tests include both the speed of the processor, and how responsive the phone is during various tasks.

How we test audio quality (external speakers)

We assess the sound quality of the external speakers with a range of different music, so you can be assured that it will do your favourite tracks justice.

How we test durability

We check the build quality of each phone by seeing how well the screen copes with being scratched and if it can survive a sudden burst of rain. If it’s waterproof, we also put the manufacturer’s IP rating to the test.