People repeat that vertical video “works better”. That is true in one sense and sold in another. We looked at what has been published, and by whom, because a platform’s figure often exists to sell its own format. Pages read on 15 October 2026.
A phone is held upright
The first argument is physical. According to ScientiaMobile’s MOVR report for the third quarter of 2017, iPhone users hold their device in portrait about 97% of the time, and Android users up to 94% on 6.5-inch screens. On a large tablet the share drops: about 27% for an iPad Pro. The page describes neither its sample nor its method, and the data date from 2017: it is an order of magnitude, not a recent measurement.
In that position a horizontal 16:9 video takes the width of the screen and a little under a third of its height (simple arithmetic: 9 over 16, divided by 16 over 9). The rest is black, or filled with something else. A vertical 9:16 video fills it all. That frame is described in The 9:16 vertical video format.
Less effort, easier processing
An academic study (Mulier, Slabbinck and Vermeir, Journal of Interactive Marketing, 2021) compared vertical and horizontal video ads on mobile. In a large-scale field study, vertical ads drew more interest and engagement. Two experiments show viewers process them more easily, and the authors explain it by effort: full screen, you do not have to turn the phone. The effect is stronger among Generation Z than Generations X and Y.
Two caveats: the study is about ads, not about an expert’s advice, and the page we read gives no sample sizes.
Snapchat’s figure, and what it is worth
The best-known claim is “nine times”. Snapchat said its users were, in some cases, nine times more likely to watch a vertical video to the end than a horizontal one. Social Media Examiner reported it in February 2016 as Snapchat’s own data, true “in some instances”, and asked whether independent studies would confirm it. Contently quoted it as early as May 2015.
So: a figure from a platform whose app is vertical, published without a method, and limited to some cases. It points the same way as the 2021 study; it does not replace it.
Sound off, and text on screen
A vertical video starts playing in a feed, most often without sound. LinkedIn says so in its page on autoplay. In a study by Verizon Media and Publicis Media, 69% of respondents said they watch videos without sound in public places; these are declared habits, published by an ad seller and an agency. We detail these sources and their limits in Video captions: watching with the sound off.
That is a second advantage of full screen: captions are large. They are not what makes vertical video more watched; they are what makes it readable.
Platforms’ figures sell their format
In June 2025 YouTube said Shorts totalled 200 billion views a day. Tubefilter points out that YouTube counts every appearance in the feed as a view. It is a volume of displays, not of time watched.
The same rule applies to surveys published by ad vendors: a survey by YuMe, reported by MediaPost in June 2017, said 79% of novice viewers found the format more engaging. The article gives no sample and no method; these are stated opinions, from a company that sells advertising.
What these figures do not say
- Conversion. We found no independent study linking vertical to more customers. The measures concern interest, engagement or completion.
- Length. A vertical video is usually short, and the shorter a video, the more often it is watched to the end. Part of the gap may come from there, and the sources do not separate the two effects.
- Content. A format holds a glance for a second. What holds it after that is the first sentence; see How long should a short be?.
- The screen. Off the phone, the argument reverses: on a television, horizontal fills the screen. Nielsen measured in July 2026 that YouTube made up 14.2% of US television time.
The choice between the two formats is covered in Horizontal vs vertical video.
What you can take from it
Posting vertical is a good choice for a video watched on a phone, because the frame matches the screen and lowers the effort. It is no guarantee of attention. You still need a clear idea in the first seconds, captions and the right length.
Dailies Studio makes its shorts in 9:16, captioned, from the calls you record, in French or in English. The format is right; the idea comes from you.
Key takeaways
- A phone is held upright almost all the time (97% for iPhone, MOVR 2017, method not described).
- A 9:16 video fills the screen; a 16:9 one uses about a third of it.
- A 2021 study of ads measures more interest and less effort for vertical video.
- The figures from Snapchat, YouTube and ad vendors come from people who sell the format.
- No source we found links vertical to more sales.
Sources
Pages read on 15 October 2026.
- ScientiaMobile, Smartphone and Tablet Portrait Orientation Usage 2017 Q3, 7 November 2017.
- Mulier, Slabbinck and Vermeir, This Way Up: The Effectiveness of Mobile Vertical Video Marketing, Journal of Interactive Marketing, 2021.
- Social Media Examiner, Snapchat Gains Momentum, 17 February 2016; Contently, Mary Meeker’s Internet Trends, 29 May 2015.
- LinkedIn, autoplay; Verizon Media and Publicis Media, 2019 study.
- Tubefilter, Shorts, 200 billion views, 18 June 2025; MediaPost, YuMe, 6 June 2017.
- Nielsen, The Gauge, July 2026, 10 September 2026.