What Is the Ideal Length Of An Online Video Ad?

Conventional wisdom says that the perfect film is two hours long and that the perfect pop song is three minutes long, but how long is the perfect online advert?

We encounter video adverts online on a daily basis. Some are promoted on Twitter, others appear in banner ads and others are spread directly across social media platforms or ‘dark social’ like email and IM. And with a spot’s ‘viewability’ (i.e. its ability to not only gain but retain a viewer’s active attention) set to become the industry marker for 2015, you have to wonder: what length of ad is most likely to engage viewers?

Ask pretty much anyone if attention spans are decreasing and they’ll say “yes”, before tuning out to check their newsfeed. Every day we’re told that the 21st Century cocktail of 24 hour news, clickbait ‘listicles’ and smartphone games have left us hopefully impatient, picking up and dropping stories the second we’re bored. Goldfish with 4G, essentially. But is this actually true?

Well, partially, yes. Unruly’s Viral Video Chart has recorded the most-shared videos online since 2006, and has a lot to tell us about what we like to spread online. Taking the average lengths of the top 20 most-shared video ads of all time, we can ascertain the optimum viral video length: short and snappy, or in-depth engagement.

When we asked this question way back in 2012, the answer was a little surprising. The average length of a video in the top 10 was a languorous 4 minutes and 11 seconds.

In other words, enough time to microwave a medium-size potato or listen to The Beatles’ “I Wanna Hold Your Hand” 1.74 times. And if you think 2012’s surprise 30+ minute epic KONY2012 was skewing the average, the video actually didn’t actually make the cut. In fact, adding in Invisible Children’s epic PSA boosted average video length of a robust 6 minutes 12 seconds.

Two-and-a-half years on, the picture has changed. Taking the current most-shared videos of all time, the average video length is 2 minutes and 53 seconds, a drop of 78 seconds from the previous average.

This shift takes some explaining. At the shorter end of things, Kmart’s ‘Ship My Pants’ comes in at a pithy 35 seconds, while 2012’s Gymkhana 4 maxes out our list at a whopping 9 minutes 15 seconds. In between, only three videos lasted over four minutes, while 10 lasted under 2 minutes.

The obvious conclusion to all this is that attention spans are getting shorter, and shareable videos along with them. While there is no denying that the length of popular video adverts has decreased in the last three years, examining the specifics of the list reveals a lot more variety.

Ken Block and his Gymkhana series may be an outlier in single-handedly dragging up the average, but trackverts (a relatively recent invention) like La La La and Cornetto’s Yalin put a natural song-length cap on their videos. Similarly, more complex set-ups that require longer exposition like Christmas Food Court Flash Mob and Pepsi’s Jeff Gordon: Test Drive are equally well-represented. So, it’s just not just bite-sized teasers that are sharing well.

The rise of short form video platforms like Vine and Instagram is one way of accounting for this shift. Although no short form videos currently make our top ads chart yet, their immense popularity in larger video sharing indicates why average video length might be decreasing on average.

Especially as more and more brands learn how to play short form to their advantage, we’re likely to see a “Win me over in 6 seconds” mindset continue to dominate the sharing sphere.

However, this doesn’t mean brands shouldn’t play outside this framework. On the contrary, there are so many other factors far more important than video length in determining a video ad’s viral spread.

Emotional engagement, motivation for sharing and choice of platform (YouTube, Facebook, short-form etc) are far more important determinants for a video’s success online. And, equally, there’s no discounting the element of surprise. For instance, who would’ve predicted an 11 minute surreal art film could have become one of late 2014’s surprise hits?

So, to all the brands currently in pre-production on an epic 8-minute spot and kicking themselves, don’t abandon hope yet. Yes, video ads may be getting shorter on average but your second count is going to make or break your spot: there’s far more to it than that. After all, good content comes in all shapes and sizes.