The display diagonal has always been the established, standard method for specifying the size of a smartphone's display. What can often be overlooked is that if two devices have a different aspect ratio, the sizes aren't directly comparable.
Currently, the LG G6 is responsible for this discussion, and the Galaxy S8 will intensify it: how can the size of one display be compared against another? The diagonal is not sufficient. The reason for this is mathematics – more precisely, geometry.
The LG G6 has an aspect ratio of 18:9 (or 2:1) and a diagonal of 5.7 inches. Because of the form factor, this means that, in comparison with another 5.7-inch display: it’s narrower, but taller. Nevertheless, there is less space on the display. In comparison with the Nexus 6P, you can see: the 16:9 Nexus has a display area of 89.6 cm² while that of the LG G6 is only 83.8 cm². So, we are dealing with a difference of about 6 cm² (the rounded display corners of the G6 are not taken into consideration).
We face a very similar problem with the Galaxy S8 and the S8 Plus: both will probably have the 1,440 x 2,960 resolution, which gives an aspect ratio of 2.06:1 (or however Samsung will refer to it).
An example illustrates the situation: if the Galaxy S8 appears with the 16:9 format, the display would be 92.74 cm² in size. However, because it will have a different aspect ratio, the display is expected to be only 85.38 cm². For comparison, the Galaxy S7 Edge presents a display area that is 83.39 cm².
Narrower, but taller: what difference does it make?
The new form factor requires a tradeoff, especially for games, because they can’t switch to the native resolution of the display. Either there are black bars at the edge, or the content at the top and bottom is cut off. To demonstrate this, here is a screenshot from Sky Dancer:
In everyday use, on the other hand, the taller display results in more content being visible. So, on a web page, there are more lines displayed in articles and a messenger can show more messages. It’s also clear that this can differ from app to app. Thanks to Nougat’s standard ability to adjust the display size of icons and text, the effect can also be slightly modified.
Display area of selected smartphones
|LG G6||1,440 x 2,880||2:1||5.7 in||6.47 cm||12.95 cm||83.84 cm²|
|LG G5||1,440 x 2,560||16:9||5.3 in||6.6 cm||11.73 cm||77.44 cm²|
|Nexus 6P||1,440 x 2,560||16:9||5.7 in||7.1 cm||12.62 cm||89.57 cm²|
|Galaxy S7||1,440 x 2,560||16:9||5.1 in||6.35 cm||11.29 cm||71.7 cm²|
|Galaxy S7 Edge||1,440 x 2,560||16:9||5.5 in||6.85 cm||12.18 cm||83.39 cm²|
|Galaxy S8 (rumored)||1,440 x 2,960||2.06:1||5.8 in||6.44 cm||13.25 cm||85.38 cm²|
|Galaxy S8 Plus (rumored)||1,440 x 2,960||2.06:1||6.2 in||6.89 cm||14.16 cm||97.56 cm²|
|Comparison: 5.8 in, 16:9||1,440 x 2,560||16:9||5.8 in||7.22 cm||12.84 cm||92.74 cm²|
|Comparison: 6.2 in, 16:9||1,440 x 2,560||16:9||6.2 in||7.72 cm||13.73 cm||105.97 cm²|
|Lenovo Phab2 Pro||1,440 x 2,560||16:9||6.4 in||7.97 cm||14.17 cm||112.92 cm²|
To explain: the data in the table were calculated with the DPI Calculator on sven.de. We assume that the pixels are square. The calculated results are from the width and height data. Actual values for individual devices may differ slightly.
Conclusion: a display diagonal is not enough for size comparison
With the new generation of smartphones from LG and Samsung, classic ideas about the size of smartphone displays have been shaken: a 5.7-inch smartphone may not be comparable to another 5.7-inch smartphone, precisely because the aspect ratios require very different housing concepts. This is the case with the LG G6: despite the display, it is quite compact and almost the same size as a Nexus 5X with a 5.2-inch display (screenshot comparison pictured above).
More data points are necessary in order to compare different displays. Display area is a good start, especially since the smallest differences become apparent. However, this too, is only a guideline. So, the appeal of the classic info about the diagonal size is that it intuitively gives you a sense of its size compared to others and the overall size of a smartphone – this is hardly possible with the addition of data points about the area.
Is your smartphone's display large enough for you to read comfortably? What do you think of the LG G6's display?