Skippable in-stream: no max length, under 3 minutes recommended

What Google's page says

Google Ads' video ad formats page (read 2026-10-09) lists skippable in-stream ads with no maximum length and under 3 minutes recommended, and says they bill per view, counting 30 seconds of watching or the whole video if it is shorter. Other rows on the same page matter if you cut several versions from one master.

The 179-second trim

If your master is 5 minutes and you want to follow the under-3-minutes guidance, the cut has to be 179 seconds or less. A video trim request takes start and either end or duration, for example start: 20 and duration: 179, and returns a new MP4 for $0.02. The duration field accepts 0.2 to 900 seconds, and the source can be up to 1,800 seconds.

{
  "video_url": "https://media.sume.com/artifacts/artf_demo/master.mp4",
  "start": 20,
  "duration": 179,
  "precision": "exact"
}

Why trim and not re-render

A Timeline render would also work, but it bills per output minute rounded up, so 179 seconds is 3 billed minutes at $0.30. A trim is a flat $0.02 per job, and it does not need an audio spine because it works on one clip. If you only need a different in-point and length, trim is the cheaper path. If you need transitions or a different soundtrack, render with Timeline.

precision: exact re-encodes with libx264 and yuv420p, while keyframe stream-copies and can start a GOP early; read actual_start_seconds in the result when you use the latter.

Version family from one master

The same page gives you the lengths for the versions you probably want from a 5-minute master. Cutting a 179-second skippable, a 59-second Shorts ad and a 6-second bumper is three trim jobs at $0.02, $0.06 in all. Billing models differ across these formats, so a longer file is not just a creative choice: skippable ads bill when the viewer watches 30 seconds or the whole video if shorter, and bumpers bill by impression.

What to check before you upload the cut

Confirm the result's duration_seconds is 179 or less, since a clamped range returns a trim_clamped_to_source warning when your end falls past the source. Then probe the file with video inspect if you want stills of the first seconds, which is where a skippable ad earns its view. The default inspect returns eight evenly spaced stills and is billed by its own compute, so it is not a flat fee.

None of this changes Google's rules for the ad itself, which live in Google Ads policy. This post covers only the length guidance on the formats page and the mechanics of cutting to it.