Demand Gen Video Specs: Sizes, Length, and Aspect Ratios (2026)

Demand Gen video ads accept four aspect ratios: horizontal 16:9, square 1:1, vertical 9:16, and vertical 4:5, with 9:16 recommended for YouTube Shorts. Uploaded video must be at least 5 seconds, but anything under 10 seconds will not serve on YouTube in-stream, so 10 seconds is the practical floor. Google recommends going past 15 seconds for reach, accepts up to five videos per ad, and takes MPG (MPEG-2 or MPEG-4) files up to 256 GB. These specs were checked against Google Ads Help in July 2026.

Demand Gen is where Google video advertising lives now that Video Action Campaigns are gone, and the spec sheet catches a lot of advertisers off guard because it is not the old YouTube video ad spec. It is a display-and-video hybrid that serves across YouTube, Discover, and Gmail, and the format rules reflect that. Here is the whole thing, with the two places Google's own pages disagree flagged so you know which number to trust.

What are the Demand Gen video specs?

Google accepts video assets in four aspect ratios and recommends uploading more than one so the system does not have to crop your creative to fit a placement. The recommended resolutions below are Google's HD targets.

On the technical side, Google recommends at least 720p, accepts MPG files in MPEG-2 or MPEG-4, and sets a ceiling of 256 GB or 12 hours, whichever is smaller, which no ad will ever come close to. You can upload between one and five videos per ad.

How long does a Demand Gen video have to be?

An uploaded Demand Gen video must be at least 5 seconds. That is the hard technical minimum, but it is not the number that matters most. Videos under 10 seconds are ineligible to serve on YouTube in-stream, so a clip between 5 and 10 seconds locks itself out of one of the largest surfaces in the campaign. Treat 10 seconds as the real floor unless you have a specific reason to run shorter.

For an upper bound, Google recommends going past 15 seconds to maximize reach, and the crop and trim tool works on source video anywhere from 5 to 300 seconds. Here is the one genuine conflict in Google's documentation, and it is worth knowing about. The detailed asset specification page lists the 5 second minimum, the 300 second trim ceiling, and one to five videos per ad. A separate, simpler Demand Gen page lists a 10 to 60 second duration and three videos per aspect ratio. The detailed asset page is the more authoritative source, so the safe read is: at least 10 seconds to stay eligible everywhere, and 10 to 60 seconds as the practical sweet spot that both pages agree is fine.

Which aspect ratio should you upload?

Upload as many as you can produce, because Demand Gen serves across surfaces that each favor a different shape. If you can only commit to one, the vertical 9:16 asset is the highest-leverage choice, and here is the reasoning. Vertical 9:16 is the format Google explicitly recommends for YouTube Shorts, and Shorts is where the cheap, fast-growing inventory sits. A horizontal-only campaign simply cannot reach that placement well.

There is a catch that trips up vertical-only advertisers, so be clear-eyed about it. You cannot buy YouTube Shorts placement in isolation with Demand Gen. Google's own help page states you will not be able to buy only YouTube Shorts ads through a Demand Gen campaign. Your ads serve across all the campaign's surfaces, and a 9:16 asset will run on Shorts beautifully but may be letterboxed or cropped on horizontal surfaces. The clean solution is to give the campaign a vertical asset plus a horizontal and a square one, so every surface has something native to serve. It is common to research what shapes and hooks competitors are already running before you commit, and an ad spy tool that pulls live competitor creative makes that a five-minute job rather than an afternoon of scrolling.

What happens if you do not upload a video?

Demand Gen will make one for you, and it is on by default. If you provide text and image assets plus brand guidelines, Google uses image-to-video generative AI to build 10-second clips, hosted on a Google-owned channel you cannot manage or edit. On top of that, two enhancement checkboxes are switched on by default: one that derives vertical and square versions from your horizontal video, and one that cuts shorter versions of whatever you upload. So even a clean 9:16 upload can spawn machine-made square, horizontal, and shorter variants unless you uncheck those boxes in the ad settings.

None of this is inherently bad, but the auto-generated version tends to look generic, and you lose control over the exact frames that represent your brand. Most performance teams would rather upload real creative in each ratio and switch the enhancements off, so the campaign optimizes between assets they actually chose. This is the same dynamic that plays out on the Google shopping side, where Performance Max video assets get auto-generated the moment an asset group has no active uploaded video.

Bidding and budget, briefly

Specs are only half the setup, so here is the rest in one paragraph. Demand Gen bidding covers Maximize clicks, Maximize conversions, Maximize conversion value, Target CPA, Target ROAS, Target CPC, and value-based bidding. Google recommends a budget of at least 10 times your target CPA, and there is no minimum budget requirement for Maximize clicks. The system needs roughly 50 conversions to establish a stable baseline, so the usual advice is to start on Maximize conversions and move to Target CPA or Target ROAS once you have cleared that mark.

The short version for a creative brief

If you are briefing whoever makes your video, hand them this: produce vertical 9:16 at 1080 x 1920 as the priority asset, keep every clip at 10 seconds or longer so it stays eligible for in-stream as well as Shorts, aim for the 10 to 60 second window, add a horizontal 16:9 and a square 1:1 version for full surface coverage, and export as MP4. Burn captions in, because a large share of Demand Gen impressions play muted in feeds.

That last point is where most of the performance difference lives. The spec gets you eligible; the hook and the caption get you watched. If producing vertical creative in volume is the bottleneck, the Demand Gen video ads workflow builds captioned 9:16 clips from a product URL, several angles at a time, so you can fill the vertical slot and still have variations to test. For the Shorts placement specifically, the YouTube Shorts ad maker covers the same ground, and if you want the underlying billing math, our breakdown of YouTube ads cost explains how each format charges.