In an 18:9 world, we need a new way to quantify screen size

By Alex Dobie
last updated

With the arrival of the 5.7-inch LG G6, we have entered the era of 18:9 smartphones. Taller displays are set to become a major trend in phones in 2017, with Samsung rumored to use an even taller "18.5:9" configuration in its upcoming Galaxy S8, which looks set to come in 5.8- and 6.2-inch flavors. Apple, too, may switch to a taller display with on-screen controls for its upcoming iPhones, which have also been rumored to use 5.8-inch panels.

In the smartphone world, we've become reliant on diagonal measurements of the screen as a way to quantify the size of a device — 4.7- to 5-inchers were small, 5.7 and up was "phablet" territory. For the most part, it worked, because we were dealing with the same aspect ratio across the board — standard 16:9, same as the majority of TVs.

But as phones with 18:9 panels start to ship, it's tempting to directly compare the diagonals with their 16:9 forerunners That can be misleading.

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Consider the two phones above, the HTC U Ultra and LG G6. Both have 5.7-inch screens, meaning, corner-to-corner, the active portion of the display measures around 5.7 inches (with whatever rounding up or down the manufacturer wants to factor in there.) But it's plain to see in the photo that the U Ultra has a way larger screen, and that's because of the basic geometry of the thing — its screen area is bigger.

After taking out a tape measure and taking some readings, here are the screen areas for these "5.7-inch" devices:

  • LG G6: 86.5cm²
  • HTC U Ultra: 90.2cm² (not including the second screen)
  • (And for good measure let's throw in the Nexus 6P: 90.7cm²)

The diagonal measurement alone doesn't tell the full story. In this instance, the 16:9 phones have a larger display area. Of course they're also much wider, which may be undesirable for one-handed use. But the point is they aren't truly the same size.

A 16:9 display at 5.7 inches is absolutely not the same as an 18:9 display at 5.7 inches

By the same token, don't expect a 5.8-inch Galaxy S8 to offer the same phablet-class real estate as a Note 5 or GS6 edge+. It'll be taller, and you may see more emails or lines of web content at once, but the screen area will be substantially different. The same argument applies to the Galaxy S8 Plus, which is around the same physical size as a Note 7.

Things become even more confusing when you recall that the G6 has software keys eating into that 5.7-inch diagonal, whereas the U Ultra, with its capacitive buttons, does not. If you exclude the portion of the screen lost to soft keys, the G6's screen area is reduced to 80.5cm². (Though admittedly, many apps can clear away the soft keys and use the full display size.) This factor alone should make the 5.8-inch GS8 feel a lot like a 5.2- or 5.5-inch phone to Galaxy owners used to off-screen keys.

That's not to say talk of phones like the LG G6 (and its contemporaries) delivering more screen in a smaller form factor is total BS. The G6 is substantially smaller than the iPhone 7 Plus, while also managing to deliver a slightly larger screen area — 86.5cm² to the 5.5-inch iPhone's 84.5cm².

Bottom line: A 16:9 display at 5.7 inches is absolutely not the same as an 18:9 display at 5.7 inches, because geometry. Equating the two is misleading at best. Screen area is a much more accurate way to pin a number on how large a screen is. So until manufacturers start printing area measurements on device boxes, we'll just have to use common sense to cut through the marketing.

Alex Dobie
Alex Dobie
Executive Editor

Alex was with Android Central for over a decade, producing written and video content for the site, and served as global Executive Editor from 2016 to 2022.

72 Comments
  • In the future when OEM stop to having good gross margin from this 18:9 panels (like it it happened with 16:9 that's why they shift for 18:9) we will have phones with 21:9, so basically we will have a sword like smartphone in our pockets. Form over function all over again
  • Well if the entire front of the G6 were screen then it may well be a 21:9 panel. Would that be a bad thing? The phone would keep the same dimensions but without the bezel. Consider the G5 to the G6. The G6 is basically the same size (a smidgen smaller actually) as the G5 - and no more sword like but the screen is significantly bigger.
  • Remember those spoof ads for the iPhone where there was a 3ft tall iPhone 6 (right after the 5 came out with one more row of icons)? This is starting to remind me of that spoof.
  • Also the first thing I thought of.
  • Is different here. The aspect ratio is not the same as screen size. A phone with 21:9 will be very tall and very narrow. That's why most android tablets are now 4:3 and not 16:9 as they use to be previously.
  • Frankly I've been shocked by the return of 4:3 tablets, I never would've predicted that would happen, there it definitely makes sense to have that aspect ratio. So this is a good thing. On the phone it seems like there are definite advantages to the 18:9 device that LG just put out. I'm not entirely convinced it's a bad thing in terms of usability. There will be apps/scenarios when it won't be ideal, but then again, it's a phone.
  • Agree...here's how it goes down:
    CEO to the Marketing Department: "people, we need something new to push" Marketing: "umm...since smartphones mostly do the same basic things and are stuck in a rut we'll come up with some new BS and tout it's benefits while basically keeping what it does in a rut. How about tweaking the screen size?" CEO: "brilliant, we'll say how it can be one-handed and do everything it did before, but we won't tell them the last part" Marketing: "yes, then everyone will come on board and the tech media will jump all over it because it's the same new old thing" CEO: "yes, and people will pre-order and stare at them for hours thinking how great the new break-through is while doing the same old thing"
  • Alternatively we can start looking at the vertical size of the entire phone. For example, instead of saying "The S7 has a 5.1" display" just say "The S7 is 14cm tall". Because in the end, what people came most about is the actual dimension of the phone, not really the screen size.
    In LG's case, it would help them to say for example that the G6 is as tall as the G5 but the screen area is bigger. That conveys the message much better than the screen size and ratio mumbo-jumbo.
  • Only mentioning the vertical height trips up with non-usual ratios of a narrower or wider phone, just look at the blackberry passport just under that metric.
  • The passport isn't really a normal device. Not only normal smartphones lack a keyboard, the aspect ratio was such a flop it was never repeated. But I understand your argument. Which can be simply solved by mentioning how tall the device is and how wide.
  • Area would probably work fine
  • Overall area? Too complicated. You'd be required to do maths to figure out the exact size of the phone.
    By mentioning how tall and wide it is, you cut the maths out of it. And it becomes simplified as you can simply pick up a ruler and see right away the size.
  • I think the size of the display when displaying a 16:9 video would be a good idea to visualize the size a smartphone with a non-standard ratio.
  • Math to the rescue!
  • Yep. And we need to stop measuring curved screens as if they were flat. We need to measure the screen as viewed from above as this is the screen size that we can actually see.
  • Actually, measuring a curved screen as a flat screen is a very good approximation. I've just done calculations about the S7 Edge, which has a display with a very high curvature (much higher than that the Note7 or S8s, for instance), and here are the results, compared to the specifications of the curved screen :
    If you take the curve into account and see it from above, you get :
    - a width of the display of 6.79 cm instead of 6.85 cm (a 1% difference);
    - a usable area of 82.7 cm² instead of 83.4 cm² (a 1% difference);
    - a 5.45-inch screen instead of a 5.5-inch screen (a 1% difference).
    As for the screen-to-body ratio of the S7 Edge, it goes from 76.1% down to 75.4%. And that was with a really pessimistic approximation for the curvature of the display.
  • So your saying that having a phone with a curved display makes the phone less than 1% thinner. Hardly an advertisement for curved displays.
  • No, I'm saying that a curved display will lower your screen usable area by 1%. But it doesn't mean that is cannot make a device less wide. The side bezels of the display, on curved smartphones like the S7 Edge, is also curved. But this bezel is necessary for most smartphones because there are electronics for the display in it.
    Imagine a display that needs 3mm of bezels on each side. If the display is curved with an angle of about 45 degrees on the side, like the S7 Edge, it means that the actual bezel will only add 1.7mm to the width of the phone instead of 3mm. The difference is significant.
  • Don't want to doubt your figures but having done some of my own calculations I have come up with the following figures. A 5.1" (12.954cm) 16:9 screen has a height of 11.29cm and a width of 6.35cm. Therefore the area of the screen is 71.69 square cm.
    Assuming a curved screen has a 3mm radius 4.7125mm of the screen is taken up by each curved side. This reduces the flat width of the screen. by 9.425mm and results in an overall reduction in the width of the screen by 3.425 mm (9.425 - 6mm). This gives an overall width of the screen as 6.0075cm when viewed from above. A screen of 6.0075cm x 11.29cm has a viewing area of 67.82 square cm which is 94.6% of the viewable area on the flat screen phone. The flat area if the screen is 5.4075 x 11.29cm giving a flat screen area of 61.05 square cm which is only 85.16% of the flat screen phone. I do not think this is a good trade off to save 3.4mm on the width of the phone.
  • That's because your hypotheses are wrong.
    The main mistake you made is that you considered that the extremity of the display was perpendicular to the flat part of the display. But that is not true. The side of the curved display makes an angle of up to 45 degrees only with the flat part of the display, not 90 degrees. See for yourself : i-cdn.phonearena.com/images/articles/261013-thumb/GalaxyNote7-Feature-Design-Main.jpg
    That changes everything! (and makes the calculations more difficult) ;) And actually, the radius of the curve of the S7 Edge is about 3.7 mm according to my own measurements, in case you're interested.
  • The whole diagonal screen size method was obviously created by men. "Hey baby, I'm packing a 6.2 incher in my pants." It'll never change, especially in this age of Alternative facts.
  • Hang on, are you sure that those areas of the display are correct? They sound huge -- the total front area of the G6 (not the screen) is 14.89cm * 7.19cm = ~108cm squared, so how are you getting the screen size as 865cm squared?
  • Lol! Yeah, that ain't right.
  • Think they got the decimal point in the wrong place. My Nexus 5X screen is 6.5cm x 11.5 cm giving an area of 74.75 square centimetres.
  • I'm sure he wanted to write mm, not cm. It's pretty obvious that our phones are not nearly 1 square meter in size!
  • PPI, screen area, screen to body ratio and HxWxD dimensions should be the standard.
  • 18:9 == 2:1
    As it seems there will not be a standard it will be better to compare with surface measures as square cm or mm plus the ratio 4:3, 16:9 or now 2:1 and others.
    Do not expect any help from brands, from 4:3 (16:12) to 16:9 they did not change the diagonal measure and in PC monitors does matter, the 24" is now even less "big" screen that 21" (4:3) where As 21/5= 4.2 and 3x4.2=12.6 and 24 /18(.36)= 1.33 and 9x1.33=12 (11.77 with the calculator) so to achieve 12.6 (21" 4:3) high, you will need to solve this 9* (x/18.36)=12.6 so X= 12.6*18.36/9= 25.7 21" 4:3 high => 26" 16:9 high and almost nobody made those conversions at the time of that change.
  • This actually places even more importance on actually looking at and holding (where possible) a phone in person.
  • I'm a screen size guy... I have the note4 and I want to go bigger. So you're saying people like me who read that 6.2 inch size of the S8plus (And jumped for joy) are under the wrong impression.
  • Now people who slept through their geometry class will go gaga over this article. Probably for now, the ratio should be accompanying the screen diagonal size when marketing. LG G6 5.7" 2:1 screen
    Qualcomm Snapdragon 830
    (i just made that up) It's like it's imperative to put what specific snapdragon the phone has - not because common people understand what it is but because geeks would want to know.
  • I agree. I still wouldn't want a phone with an 18:9 screen. It's way too tall. Had they used a 16:9 screen in the same size with the same bezels the phone would be perfect.
  • I had thought this was going to talk about how stupid the ration 18:9 was when it was actually just 2:1. Obviously not where you were going. LOL!
  • The sad thing is I've already noticed my switching from a 16:10 to a 16:9 phablet (Huawei Mediapad X1 to Xiaomi Mi Max) wasn't that great of an idea for reading (which I do a lot) and the occasional Office work (which I do very rarely). I think I wouldn't like 18:9.
  • And what do you get when you play a 16 by 9 movie on an 18 by 9 screen? I am going to guess that it is actually a smaller picture with dead space on the sides? Can someone with an 18x9 do a side-by-side comparison?
  • These 18:9 phones are narrower so the available "height" to fit in the 16:9 video in landscape mode will be less. The corresponding "width" of the video will be reduced as well. Result: A smaller viewing area with vertical black bars on both sides of the screen. It's akin to watching old 4:3 television shows on newer 16:9 televisions.
  • When you play a 16:9 movie on a 18:9 X-inch display, the area of the display that is used is exactly the same as if you were playing this movie on a 16:9 Y-inch movie, where Y=0.91*X.
    For instance, when you play a 16:9 movie on the LG G6, which has a 5.7 inch display, it's as if you were playing it on a 5.2 inch 16:9 screen. Which means that a movie would look bigger on the LG G5 (5.3 inch) than on the LG G6!
  • Simple: you see the film in 16;9 and get those lovely black bars on the side. And if the picture isn't anamorphic, you might get black bars on top as well. Yay, black bars galore!
  • Standard parameters for defining screen should be:
    1. PPI
    2. Screen area: sq.cm or sq. inches
    3. Screen height: cm or inches
    4. Screen ratio Screen diagonal makes no sense at all when comparing different ratios and can be very misleading. This simply seems to be a ploy to get the average consumer to fall for the marketing pitches of bigger is better where they may actually be getting smaller screen real estate in these so called 5.8" "large" screens. The behind the scenes story is not user convenience, it's better profit margins due to savings on screen cost.
  • Just when you thought vertical video couldn't get any more annoying...
  • Why is this still being marketed as 18:9? It's just 2:1 ratio.
  • Because it makes for an easier and more intuitive comparison to the 16:9 standard.
  • Because people are stupid and it sounds cool. They're just conditioning us to the flexible clam shell phones to come.
  • Well, I was looking forward to the new S-line but judging by this it will be smaller than my Note 5! In hope it will get Nougat soon I probably gonna stick with it. Oh, damnable choices!
  • I'm curious as to the note actual screen size vs the S8+ actual screen size also.
  • I hope to god they dont ruin the Note with this stupid decision. If they could just pack the SAME 5.7" screen on the Note 7 and place it inside a body that has the absolute minimal top and bottom (and side) bezels, I would be SOOO happy. Especially if the bottom bezel was as short as it is on the S8 AND had the capacitive buttons built into them (not including the FP, have that under the screen xD). I've been wanting a really minimal bezel phone for YEARS, and I KNOW I'm not alone.
  • If we didn't change the way we measure television screen sizes, why would change for phone screens? This seems silly.
  • As long as the comparisons are Apple to Apple (no pun intended) it is ok to measure by one standard - in this case screen diagonal. But when there are multiple ratios using a diagonal as a measure of comparison can be misleading. TV's moved from 4:3 to 16:9 period. But looking at the sheer number of phones being sold there will definitely be multiple screen formats selling in parallel at the same time. It is important then to define screens by their screen real estate, height and width - not their diagonal.
  • The difference with TVs is we went from an older 4:3 aspect ratio to a new 16:9 ratio, and nearly all TVs have the same aspect ratio ... so the comparison is fine. Nobody is comparing a new 16:9 display to an old 4:3 one anymore. In phones, we're looking at situations in which people are legitimately comparing 16:9 phones to 18:9 or 18.5:9 phones.
  • Exactly - and we have 4:3, 16:9, 21:9 and other sizes for computer monitors and they all use diagonal measurement. The existing standard for screen size is diagonal measurement PLUS screen ratio. No need for anything else. That already IS the standard, has been for 40 years, and it works fine.
  • No, it doesn't work fine. Especially if you want a multi-monitor setup with different monitors, it's a headache to find out the height of your display, like if you want to use a 21:9 display with a 16:9 one. If manufacturers told the height and width of the display you won't need to find out the ratio or the diagonal length as all the info is in there in 2 numbers instead of 3 and more useful even. And it will even help in finding out how much bezel is there in your monitor or phone.
  • Original Note with 16:10 plus soft keys was ideal size. I like the width, but all current large screen devices are a little taller than I would prefer. Though I'm not complaining about a little extra for front speakers on Nexus 6 or 6P. They are taller but have the speakers and on screen buttons make display about the same.
  • I just had a scary thought while reading this. Will we now also have a new ratio for photos?
  • They want you to see 18:9 and say Wow! that is bigger than 16:9! They chose that number very carefully to show while it's the same width, it is taller. Otherwise they would have just said what 18:9 really is --> 2:1 which actually seems silly. And also, the talk of 21:9 is silly because that is really 7:3 which 75% longer than a 4:3 screen; that is just crazy.
  • So is their a way I can find the 16:9 equivalent of an 18:9 screen size? Like apple went from 3.5 to 4 inches with the iPhone 4s to 5.
    So isn't the g5 like a taller 5.x inch 16:9 screen?
  • I'm pretty sure 16:9 video will look about the same on the 6.2 inch s8 plus as the 5.7 inch note 7. The screen widths are about the same. So the s8 plus sounds about perfect for me.
  • I'm pretty sure they just up sized you into the "larger" and substantially more expensive phone.
  • Great points! And as you mention towards the bottom of the article, a 5.7" screen that has off-screen buttons is NOT the same as a 5.7" screen with on-screen-only OS navigation buttons. I always took this into account when phone shopping for my next phablet, but i think a lot of people don't when comparing specs.
  • I definitely do. Even with the S8's impressive bezels, it still equates to a larger bottom bezel when considering the nav buttons, and that's compared to its predecessor. The only way this thin bottom bezel is going to work, is if its SUPER thin (around 3mm?), just enough to hold, or the bottom bezel that is on the S8 now, also has capacitive buttons (maybe not the fp scanner?). But again, the S8's bezels now are too tall for simply just being there. Nav buttons, or eliminate them entirely. Nothing els
  • Is samsung really 18.5:9 when the .5 is for screen buttons
  • We need to move to 2 measurements to describe a phone, like "this phone is a 200/150", which would mean it's 200 mm squared total amount of phone surface area with a 150 mm squared screen area. Simple, and don't need to worry about diagonal dimensions (which I always thought was a strange way to measure anyway) or aspect ratio. Plus, that would instantly tell you how much bezel is on the phone.
  • Why they didn't just shrink the device and make it less wide, maintaining the same, large 5.7" screen, rather than making this odd size, stupid rounded corners, thicker side bezels.. It's beyond me. I understand that the rounded corners is one of those inevitable things that we will have to get used to once the entire front panel of phones are all screen, so the display will naturally be rounded, making rounded screens now more of a transitional feature more than anything.. But still... Lets shrink the tallness and width of these 5.7" phones as we are able to eliminate the bezels.. OEM's, if you want to release a bigger phone, well then... Do it right. None of this 30:9 crap.. Just give us a 16:9, upscaled 6" device inside of your average 5.7" device. Simple as that! EDIT.. One last thing.. The whole screen to body ratio thing for me at least is an indication of how usable the device is. For instance, if I know the screen is 5.7" and the STBR is 90%, then I can tell just from the numbers that the phone is incredibly short and has super thin bezels, which is essential for a truly usable device. With the iPhones massive bottom (specifically), the device is very hard to use fully, whereas the Note 7 in comparison is WAY easier, and a Note 8 with super thin bezels would be THAT much easier to use. We could almost fit an entire 5.7" screen inside the body of a Nexus 5.. And that thing feels like a kids toy compared to other phones.
  • It's the same thing that happened with tvs. A 50" 4:3 tv has a bigger screen area then a 50" 16x9 tv. We'll get used to it.
  • If you watch a 2:35.1 or 2:40.1 movie though it should fill the entire screen and not have any black bars on the top/bottom of the screen
  • there will still be black bars but smaller. 2:1 is not the same as 2.35:1 right? so 2:1 for movies is good but for youtube not.
  • I say just go with cm².
  • This to shall pass. Nothing like a fad.
  • Why don't they just put cell modems in tablets, and call it a day, already!
  • These new screen ratios sound like a drag. I'd hate viewing video surrounded by black borders.
  • U r absolutely, completely 100% right. I just hope users come to their senses and start demanding 16:9. This fad of 18:9 needs to go ASAP
  • I approve the new screen format. I do not approve the withdrawal of p2.Ali, yes, it was a setback.
  • To the manufacture reading these comments. Please offer the following on a phone:
    1. 6" diagonal - 16.9 ratio - 2K viewable flat screen without nav. buttons.
    2. Design the web browsers so that the text flows within the frame when zooming in or contracting the page for reading purposes. I am tired of having to scroll left and right when reading articles.. - HTC's browser on the M8 was the last browser I am aware of with this functionality.
  • Opera still has text wrapping. IMO, a mobile browser is useless without that function.