Today’s guest post comes from Daniel Dur, edited only for formatting.

The overrated screen enlargement  – 16:9 to 18:9

I was a fan of wide screens. Starting with my first 16:10 laptop some 9 years ago and going through all my 5 smartphones, that were all 16:9 (even in a time when 16:10 was the norm). Somehow, I never understood 4:3 screens and this is one of the reasons I didn’t like the first iPhones and the iPads.

Fast forward to 2017, I am a proud owner of a OnePlus 5. I really like it, including it’s 5.5″, 16:9 aspect ratio screen, with capacitive navigation buttons. Yeah, good old off-screen capacitive buttons. I know, some (including Google) find them old-fashion, but not me.

But, because the good things don’t last long, since a few days ago there is a roumor floting aroung that OnePlus is going to lunch a 5T, with 6″ screen, in a 18:9 aspect ratio. The screen is suppose to have the same width, both in terms of mm and pixel count. Just its length will be a little longer. The bezelless trend is suppose to hit OnePlus too and blow the buttons from the bezels to the screen.

Fine, bigger screen, more pixel count, a different aspect ratio, a big screen that’s hand friendly. Until you spot the catch:
THE USABLE SCREEN SPACE (when not in full screen apps) WILL NOT BE THAT MUCH BIGGER!

Let’s do the math:

A 5.5″ (139.7mm) diagonal on a 16:9 screen would make the screen be about about 121.8mm × 68.5mm in size. A 6″, 18:9 screen with the same width will have a 136.3mm length. So the difference between the two screens’ length is 14.5mm. Let’s set this aside.

According to Google, the navigation bar should be 48dp.  We can use this formula to convert dp (Density-independent pixels) to pixels: px = dp * (dpi / 160). At 400dpi, 48dp = 120px.

Third point is shorter: 2160px – 1920px = 240px.

Which brings us to the conclusion: the bigger screen is going to be 240 pixels taller overall, but most of the time is only going to be only 120 pixels taller because the rest of the 120 pixels are usually going to stay occupied by the navigation bar. The other side of the story is the thin bottom bezel: no matter how thin it will be, it would only be fair to add about 7.25mm to that size (the physical size of the navigation bar).

In the end I want to emphasise that the rumored OnePlus 5T is only used as an example here. I have nothing against it and a similar situation can be found when comparing other phones like the S7 and S8, respectively.

Just don’t get totally bought by the advertising and believe everything!