How long should your AI video be? Length per platform

The ideal length of an AI video depends on where you post it: for Reels, TikTok and YouTube Shorts, short clips of roughly 7 to 30 seconds usually perform best, while explainer and story videos can run longer. With AI video there's an extra factor, because you pay per second of render and most models only generate a few seconds at a time. Length is therefore a choice about attention, technique and cost all at once.

Below you'll see how long a video can be per platform, what works best in practice, and how to build a longer video out of short AI clips.

Why length matters more with AI video

With regular video, a longer clip mainly costs you extra editing time. With AI video, every extra second also costs real money, because you pay per second of render. A ten-second clip simply costs more than a five-second one.

On top of that, AI video models usually work in short chunks, often around five to ten seconds per render. If you want a longer video, you combine several clips. Thinking short and focused pays off twice: you hold the viewer's attention and you keep your costs low.

How long can a video be per platform?

The maximum length varies by platform, but it's almost always well above what you need for social content.

• YouTube Shorts: up to 3 minutes. Since October 15, 2024, vertical or square videos up to three minutes count as a Short (according to YouTube Help).
• Instagram Reels: several minutes in-app, and longer when uploaded. Even so, Reels under 90 seconds have the best chance of reaching new audiences (according to Buffer).
• TikTok: up to 10 minutes recorded in-app and up to 60 minutes when uploaded (according to Metricool). In practice, most popular clips stay well under a minute.

The common thread: you're allowed to go long, but shorter almost always wins on these platforms, because the algorithm rewards viewers who watch your clip all the way through.

What is the ideal length per goal?

Choose your length based on what the video needs to do, not on the maximum.

• Scroll-stopper for Reels, TikTok or Shorts: 7 to 15 seconds. One strong idea, landing right away. The shorter it is, the higher the chance people watch to the end and replay it.
• Mini-story or product demo: 15 to 60 seconds. Enough room for a beginning, a middle and an end, without losing attention.
• Explainer, tutorial or website video: 1 minute or longer. Here your audience watches on purpose, so you can expand. Still, build a video like this from several short, sharp clips.

How to build a longer video from short clips

Because an AI model only makes a few seconds per render, a longer video comes together by stacking smartly. Plan in advance which shots you need, just like a storyboard.

1. Write a short prompt per shot: subject, motion and camera.
2. Generate the individual clips in the video generator, or first make a starting frame in the photo generator and bring it to life.
3. Place the clips back to back in your edit, or use the video-extend feature to let a clip continue in a chosen direction.

That way each individual render stays short and affordable, while the end result is still a continuous story.

Keep your costs in check

Because you pay per second, a tight plan is literally worth money. Decide in advance how long each clip should be, and don't default to the maximum duration "just to be safe."

A sharp prompt helps here too: the clearer you describe what happens in those few seconds, the fewer test renders you need. Not sure how to describe a clip? The prompt generator turns your idea into a complete description with motion and camera.

Frequently asked questions

How long can a YouTube Short be?

Since October 15, 2024, vertical or square videos up to 3 minutes count as a YouTube Short. For the best watch time, you usually stay well under a minute.

What is the best length for a Reel or TikTok?

For reach and a high completion rate, 7 to 30 seconds usually works best. Reels under 90 seconds have the best chance of reaching new audiences, according to Buffer.

How many seconds does an AI video model generate at once?

Usually around five to ten seconds per render, depending on the model. For a longer video, you combine several clips or use the video-extend feature.

Ready to make your first clip at the right length? Create an account and generate a short, sharp video that fits your platform exactly.