One important decision you will need to make about your video is its length. While many people will tell you the length of the video has important implications for metrics and a platform’s algorithm, there’s a more important, maybe surprising, factor for deciding on the length of a video.

To illustrate this point, let me roll back the years. When I was much younger, I did a lot of public speaking. It didn’t take long before I reached that ultimate challenge every presenter should face – speaking to teenagers. Teens present a unique challenge in that they aren’t easily impressed and they will gladly show you how disinterested they are, given the chance.

Maybe they have plenty of time to hone these rare talents through hours and hours of class time in schools. Maybe it’s just an inherent, instinctual trait they are born with. Maybe they will grow out of it. But for whatever reason, they don’t are one of the toughest crowds to speak to.

So when faced with this unicorn in the world of public speaking, I seized the moment, and asked a mentor how long I should speak. This grizzled veteran pied piper of adolescents didn’t hesitate to tell me the secret. “How long should you speak to teenagers? Not one second more than they want to listen.”

I was a bit underwhelmed by the advise.

It turned out to be true, though, as I later learned. The same is true for videos. How long should your video be? Not one second longer than anyone wants to watch.

Let’s unpack this

It’s true that certain platforms favor content packaged in a specific time. Facebook is trying to crack this formula, but hasn’t settled yet. Instagram has moved from under 15 seconds to longer running videos. YouTube, the ruling platform for videos, has moved from loving short-form content to liking longer-form content (It keeps people watching longer, right?!).

All of these platforms want to keep attention for as long as possible. They fear boredom like I feared it in my teen audience, because when boredom comes, attention leaves. Whatever impact you thought you might have becomes irrelevant. Apathy is the enemy of social media.

Regardless of a platform’s preference or any metrics you can apply to a video, if your audience stops watching, your impact is over.

So how do you plan a video’s length? The only way to plan the length is by measuring attention

Hacking attention

The reason our videos are different is because we concentrate solely on hacking peoples brains through their eyes. It’s not really even attention. It’s really connection. Attention is petty. Likes, hearts, thumbs-up, are easy to get and easy to for-get. Sparking joy, creating an emotional reaction, turning apathy into interest – that’s what video is made for. It’s why video will always outperform text on a screen and simple graphics. Connection is what we’re made for.

Every video you plan should use every second to transform the viewer. It should attempt to transport them from their mundane life into something new. It should inspire. It should impress.

As long as you can do that, you can make your videos as long as you want. Peter Jackson, the director of the Lord of the Rings movies, asked movie-goers to sit through the longest movies in modern cinema. Then he released longer versions of the films for home viewing. And people bought them! He understood the fan base of the books and capitalized on them.

If you want to move an audience, for entertainment or for marketing, the best thing you can do is plan for their eyes to wander and hold it off as long as possible. And then stop. If your video is seven seconds, that’s fine. If it’s ten minutes, go for it. But don’t ask them to watch one second longer than they want, or you’ll pay for it in apathy.