How long should an ad be? Video ad lengths by platform

How long an ad should be depends on where it runs: there is no single right length, and each platform publishes its own limits and recommendations. YouTube bumper ads are 6 seconds, Google recommends 15 seconds for skippable in-stream and in-feed video ads, Facebook plays in-stream and Stories ads of 15 seconds or less in full, X recommends 15 seconds or less, and Snapchat recommends keeping Sponsored Snaps under 10 seconds.

The platform numbers below are quoted from each platform's own help or ads-guide page, read on 2026-09-27. They are each platform's recommendations and limits, not a promise about results, and they can change. The Sume facts come from Video generation, Timeline 1.0, Video trim, and Generate avatar video.

What length does each platform recommend for video ads?

Some pages set a hard range and a separate recommendation; Meta's pages add the length that plays in full. TikTok's in-feed page lists a maximum but no recommended length. Ratios, sizes, and safe zones are in the spec posts for Meta Feed and Reels, TikTok, and LinkedIn.

What happens if a video ad runs longer?

Past the full-play length, several placements cut the ad short or split it, and one sets a floor:

• Facebook in-stream shows the first 15 seconds of a longer ad and then truncates it; viewers can resume it from a context card below the main video. Meta adds that its desktop and mobile duration limits may vary by objective.
• Facebook Stories splits an ad longer than 15 seconds into separate Stories cards and shows one, two, or three before offering Play Full. Instagram Stories may split an ad of 16 seconds or longer.
• YouTube Shorts plays only the first 60 seconds of a longer ad in the Shorts feed, with an overlay at 50 seconds that lets viewers watch the rest on the YouTube watch page.
• Too short matters too: Demand Gen videos shorter than 10 seconds won't serve on YouTube in-stream.

Which ad lengths cover the most placements?

Reading the table together (our summary, not a platform rule): a 6-second cut fits YouTube bumpers and Snapchat's under-10 advice; a 15-second cut plays in full on Facebook in-stream and in both Stories placements and matches Google's and X's recommendation; and a 30-second cut meets Demand Gen's more-than-15 and LinkedIn's 15–30. All three stay under the Shorts recommendation of 60 seconds. For bumpers specifically, see YouTube bumper ad specs.

How do I make a video ad at an exact length with AI?

Decide the cuts first, then make each one at its length. With Sume, the length is set in a different place on each surface:

• One generated clip: duration in whole seconds, from the model's supported_durations on GET /v1/videos/models. Most models stop at 15 seconds; seedance-2.5 (4–30 s) and wan-3.0 (2–30 s) make a 30-second clip in one generation.
• A talking presenter: an avatar video accepts a script Sume estimates at 4–60 seconds. Shorten a longer script or split it into several jobs.
• Several clips with a voiceover or music: a Timeline 1.0 render's length is audio.duration_seconds (1–1,800 seconds), so the 6-, 15-, and 30-second versions are one render each.
• One finished Sume-hosted clip: video trim cuts a range into a new MP4 with start plus end or duration (0.2–900 seconds), and keeps its audio unless you send audio: "drop". Cut on a pause, not mid-word.

curl -X POST https://api.sume.com/v1/video-trim \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: ad-cut-6s-001" \
  -d '{
    "video_url": "https://media.sume.com/artifacts/artf_demo/ad-master.mp4",
    "start": 0,
    "duration": 6
  }'