Muze AIIn short
YouTube ad specs are defined by format rather than by file size. Bumper ads are capped at 6 seconds. Non-skippable in-stream is commonly documented as up to 15 seconds, with 20 seconds permitted in some markets. Skippable in-stream can run long and becomes skippable after 5 seconds, which makes the first 5 seconds the only guaranteed exposure you have. The stable ratios are 16:9 for standard in-stream and 9:16 for Shorts, with 1:1 accepted on some surfaces. On Shorts the interface overlays the title, channel name and action buttons, so keep essential text out of roughly the bottom quarter and the right edge. Durations and market exceptions change, so check Google Ads Help before final delivery.
Check this before you ship
Ad specs change, often quietly. Aspect ratios are stable and safe to build against. Exact pixel margins, file size ceilings and duration caps are not, and reserved interface areas differ by placement and by app version. Treat the numbers on this page as a starting point, then check the platform's own current specification before you sign off on a production file.
Last reviewed: . Official sources: Google Ads Help Centre, video campaigns (official), YouTube Help Centre.
The rule that outlives every redesign
Keep essential text and branding toward the centre of the frame, and preview the ad in the real placement before you launch it.
Assume nobody watches past the fifth second. Put the brand and the offer inside it, then earn the rest.
Everything below is detail on top of that. Ratios are the stable layer and are safe to build against. Pixel margins, file size ceilings and duration caps are the volatile layer, which is why they are marked as commonly documented rather than stated as fact.
YouTube aspect ratios by placement
| Format | Aspect ratio | Duration |
|---|---|---|
| Skippable in-stream | 16:9, 9:16 and 1:1 accepted | Skip becomes available after 5 seconds. Long runtimes are permitted. |
| Non-skippable in-stream | 16:9, 9:16 and 1:1 accepted | Commonly documented as up to 15 seconds, with 20 seconds allowed in some markets. |
| Bumper | 16:9, 9:16 and 1:1 accepted | Maximum 6 seconds. No skip. |
| In-feed video | 16:9 preferred | No fixed cap. Thumbnail and title carry the click. |
| Shorts | 9:16 | Short by definition. Build for a vertical, sound-on-optional loop. |
| Masthead | 16:9 | Reserved buy, arranged with a Google sales contact. |
Duration rules differ by market and Google has revised the non-skippable cap before. Confirm in Google Ads Help for the markets you are running in.
Safe zones, as a share of the frame
In-stream ads run inside a player, so the risk is player chrome across the bottom. Shorts is the placement that genuinely covers your frame, and it covers it in the same places Reels and TikTok do.
Percentages are used here on purpose. Pixel margins go stale every time an app ships a redesign, whereas the proportion of the screen the interface occupies moves far less. Reserved areas still vary by placement and by app version, so treat these as a design margin rather than a measurement. For the concept itself, see safe zone in the glossary.
| Placement | Keep clear | What sits there |
|---|---|---|
| Shorts | Roughly the bottom 25 to 30 percent and about the right 12 percent | Video title, channel name and call to action across the bottom. Like, dislike, comment, share and sound controls down the right. |
| In-stream, 16:9 | The bottom strip of the frame | Player controls, progress bar, the skip button in the lower right, and auto captions when a viewer has them on. |
| In-feed thumbnail | Assume a duration badge in one corner | Runtime badge and, in some surfaces, a sponsored label. Do not put a word you need in that corner. |
These percentages are widely used working figures, not published constants. Confirm against the official specification above, and preview the creative in the live placement before sign-off.
File and asset requirements
| Item | Commonly documented value |
|---|---|
| Hosting | The ad video is an upload on your own YouTube channel. It can be unlisted. |
| Upload ceiling | Up to 256 GB or 12 hours, whichever comes first |
| Thumbnail | 1280 x 720, JPG or PNG, under 2 MB |
| Recommended resolution | 1920 x 1080 for 16:9, 1080 x 1920 for 9:16 |
| Captions | Supply a caption file rather than relying on auto captions |
The upload ceiling is a YouTube platform limit rather than an ads limit, and it is not the constraint you will hit. Duration rules are.
Text fields on video campaigns
| Field | Commonly documented limit |
|---|---|
| Headline | Short. Assume you have roughly a line. |
| Long headline | 90 characters |
| Description | 90 characters |
Field limits differ between video campaign subtypes more than they do on search. The campaign builder enforces the live number, so use it as the source of truth rather than a published table.
The skip button is the only spec that matters
On skippable in-stream, five seconds is the whole guaranteed impression. Everything after it is optional viewing you have to earn, and most viewers do not grant it.
This is why a 6 second bumper and the first 6 seconds of a longer edit are usually the same creative problem. Solve that, and the rest of the runtime is for people who already chose to stay.
Vertical is now a first class citizen
Shorts inventory is served from the same video campaigns as in-stream, so a 16:9 only asset gets letterboxed or pillarboxed into a vertical surface where every competing piece of content is full screen.
Supplying a genuine 9:16 cut is the single highest value production decision on YouTube right now, and it is the one most brands skip because they already have the horizontal file.
Sound is on, but do not rely on it
YouTube is a sound-on environment relative to a social feed, which tempts brands into audio-dependent creative. Shorts scrolling and muted autoplay surfaces break that assumption.
Burn in the key line as on-screen text, keep it out of the bottom quarter on vertical, and supply a caption file.
Frequently asked questions
- How long can a YouTube ad be?
- It depends on the format. Bumper ads are capped at 6 seconds. Non-skippable in-stream is commonly documented as up to 15 seconds, with 20 seconds permitted in some markets. Skippable in-stream can run considerably longer, but the viewer can skip after 5 seconds, so the effective length is 5 seconds plus whatever you earn.
- What is the YouTube Shorts safe zone?
- The central area of a 9:16 frame that the Shorts interface does not cover. The bottom carries the video title, channel name and call to action, and the right edge carries the like, comment and share buttons. Keeping essential text and branding out of roughly the bottom quarter and the right 12 percent is the widely used guidance, and the exact reserved area changes with app releases.
- What aspect ratio should a YouTube ad be?
- 16:9 for standard in-stream, commonly 1920 x 1080. 9:16 for Shorts, commonly 1080 x 1920. Both are accepted in video campaigns, and supplying both means your ad is native on whichever surface it serves rather than letterboxed into one of them.
- Do I have to upload the video to YouTube first?
- Yes. A YouTube video ad references a video hosted on a YouTube channel. It can be set to unlisted, so it does not have to appear on your public channel page.
- What size should a YouTube thumbnail be?
- Commonly documented as 1280 x 720 in JPG or PNG, under 2 MB. That matters for in-feed video ads, where the thumbnail and title do the work of persuading someone to click rather than the video itself.
- Is a bumper ad worth running at 6 seconds?
- Six seconds is enough for one idea and one brand impression, which is the correct expectation. It is a poor format for explaining anything and a good one for repetition, so it works best alongside a longer skippable edit rather than instead of it.
Related
Other platforms
Specs are the easy half
Getting the file right is one afternoon. Knowing which creative is losing money this week is the other job. Muze reads Meta, Google, Amazon and Shopify from ChatGPT or Claude and tells you. Every change previews before it runs, and new campaigns are created paused.
See how Muze works