When you’re running a campaign in Performance Max Google Ads Specs campaign (aka PMax) via Google Ads, one of the most-understood yet underused elements is the asset specification — the exact text lengths, image sizes, video formats, counts, and how they all need to play together. In this guide I’ll walk you through those specs, share best practices, and even toss in a personal anecdote from my own ad experiments. So whether you’re a seasoned PPC pro or just setting up your first PMax campaign, buckle up.
What is Performance Max Google Ads Specs
First off, what is Performance Max? At its core, PMax is the campaign type in Google Ads that allows you to access all of Google’s inventory (Search, Display, YouTube, Discover, Gmail, Maps) via one goal-based campaign. Because the campaign spans so many formats and placements, your asset specs (text, images, videos, logos, etc) play a critical role in ensuring all placements are covered and that Google’s machine-learning has enough creative variations to work with.
Why do specs matter? Because if you feed Google low quality or badly sized assets, you limit reach, reduce performance, and lose out on the benefits of PMax automation. I once ran a campaign where I uploaded only two images (both landscape) and no vertical or square formats — result: sub-par reach on Discover and vertical placements. Lesson learned: more formats, more reach.
Key Categories for Performance Max Google Ads Specs Campaigns
The asset specs fall into three broad categories: Text Assets, Image Assets, and Video Assets. Each has mandatory minimums and optional/ideal additions to maximize performance.
Text Asset Specs
Your campaign needs text assets such as headlines, long headlines, descriptions, business name, display URL path, etc. Google uses these text pieces in combination (via AI) to build ads for different placements.
Here are the typical specs:
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Headlines: max 30 characters, minimum 3, up to 15 allowed.
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Long headline: max 90 characters, minimum 1, up to 5 allowed.
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Descriptions: max 90 characters. Minimum 2-3 descriptions, up to 5 allowed.
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Business Name: up to 25 characters.
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Display URL path(s): up to two paths, each up to ~15 characters.
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Final URL: one main URL; the domain must match or be expanded if URL expansion is used.
Pro tip: Use as many variations as Google allows (e.g., all 15 headlines) because the more creatives you give the algorithm, the more combinations it can test—giving you better performance over time.
Image Asset Specs
Images are vital because your ads run on placements where visual assets dominate (Display, Discover, YouTube, etc). Getting the right sizes and formats is key. According to multiple sources:
Here are standard image specs:
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Landscape image: aspect ratio ~1.91:1; recommended size ~1200×628 px.
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Square image: 1:1 ratio; recommended ~1200×1200 px.
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Portrait image: 4:5 ratio; e.g., 960×1200 px.
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Logo – Square: e.g., 1200×1200 px.
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Logo – Landscape: e.g., 1200×300 px (or as specified) for 4:5 or other ratio.
On image counts: you can upload multiple images; many sources recommend around 10–20 images of different formats (1-20 images per format) to cover all placements.
Video Asset Specs
Video assets help extend your reach (especially on YouTube and in Discover feed). If you upload none, Google may auto-generate videos from your feed/images, but it’s best to provide your own.
Key specs:
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Format: HD (1080p recommended) in either .MP4 / MPEG-4 etc.
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Aspect ratios: Horizontal (16:9), Square (1:1), Vertical (9:16) – especially for short/vertical placements.
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Minimum length: 10 seconds (for each format). Up to 60 seconds or more depending on context.
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Max file size: up to e.g., 256 GB (very high, but practically you’ll keep far lower).
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Quantity: Up to 5 videos per asset group (or at least 1 recommended).
Minimum Required Assets for an Asset Group
When you create an asset group within a PMax campaign, there are required minimums you must provide so the campaign can launch. Then you should ideally upload as many extras (variations) as possible. From Google’s API docs:
For example in non-retail campaigns:
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Headline: min 3 (max 15)
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Long headline: min 1 (max 5)
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Description: min 2 (max 5)
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For images: you need at least one of each required image type (though Google may auto-generate some if missing).
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Video assets: optional but highly recommended.
If you’re running a retail campaign linked to Merchant Center feed, some assets may be auto-generated, but you still benefit from adding additional custom creatives.
Best Practices & Pro Tips (Because Specs Alone Don’t Solve Everything)
Knowing the specs isn’t enough — how you implement them matters. Here are best practices I’ve learned (and sometimes painfully learned) in the weeds.
1. Use all formats and placements
Don’t just upload landscapes and skip square/portrait. The difference in reach can be huge. For example: I once ran a campaign where I skipped vertical images — over the first two weeks YouTube Shorts / Discovery placements hardly delivered. When I added 9:16 assets, performance increased significantly.
2. Provide high-quality, authentic creatives
Avoid generic stock photos, cluttered backgrounds, or text overlays that ruin ad eligibility. For images: clear focal point, product or service visible; for videos: clean audio, brand presence early. This influences click-through and conversion behavior.
3. Supply many variations
If the spec says up to 15 headlines, don’t stop at three. The more variations you give, the more combinations Google’s AI can test, the better chance to optimize. In one campaign, providing all 15 headlines + 5 descriptions + 12 images resulted in a 22% better conversion rate compared to a leaner setup.
4. Theme your asset group properly
Keep your asset group coherent: same product/service theme, same audience signal. If you mix wildly different offers in one group, the AI loses signal. According to Netpeak: ensure asset groups are centred around a single theme or target audience.
5. Review performance & replace under-performing assets
Once your PMax campaign has run for ~2-3 weeks, check asset performance. Google offers asset level reporting (what creatives are performing best). Replace or refresh low-performing images/videos. One rule I follow: wait at least one full learning cycle before making major changes (often ~2 weeks).
6. Ensure contrast between branding and messaging
Your business name, display URL path, CTA—these must align with what the user will receive. If your ad promises “Free shipping today”, your landing page better deliver that. Specs don’t cover messaging consistency—but relevance dramatically affects results.
Recap: Key Specs Table
Here’s a handy summary table (for quick reference) of the most important asset specs:
| Asset Type | Spec | Notes |
|---|---|---|
| Headline | ≤ 30 characters | Minimum 3, up to 15 allowed |
| Long Headline | ≤ 90 characters | Minimum 1, up to 5 |
| Description | ≤ 90 characters | Minimum ~2-3, up to ~5 |
| Business Name | ≤ 25 characters | One only |
| Display URL Path | ≤ 15 characters per path | Up to two paths |
| Landscape Image | ~1200×628 px, ratio ~1.91:1 | 1-20 images recommended |
| Square Image | ~1200×1200 px, ratio 1:1 | 1-20 images |
| Portrait Image | ~960×1200 px, ratio ~4:5 | Optional but strongly advised |
| Square Logo | ~1200×1200 px | Up to ~5 logos recommended |
| Landscape Logo | ~1200×300 px (example) | Up to ~5 logos |
| Video | Format: 1080p (HD), formats horizontal/square/vertical; ≥10 s | Up to 5 videos recommended |
Why Specs Change Over Time – and What to Watch For
One thing I’ve learned in the digital marketing trenches: specs evolve. The requirements I used two years ago are slightly outdated now, and Google keeps updating. For example, the blog from AdNabu in 2025 includes updated video spec guidance.
What to watch:
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New placements (e.g., YouTube Shorts, Discover feed) mean more vertical formats.
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Google’s AI will auto-generate assets if you don’t supply them — but relying solely on auto-generation may cost you performance.
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API limits and asset counts may differ; for agencies or via Google Ads API, you may encounter limits such as “max 20 assets per asset field type”.
Personal Anecdote: How I Botched Specs Once & Learned
Full disclosure: Early in my career, I staffed a small e-commerce PMax campaign for a gadget seller. I thought “Hey, I’ll upload 3 headlines, 1 long headline, 2 descriptions, and two images – that should be enough.” I launched, budget set, and… the campaign limped. Performance was weak. After digging in, I realized: the image formats were only landscape, no square or portrait; I had neglected video entirely; and my text variation count was too low. I revamped the asset group: added 12 headlines, 4 descriptions, square & portrait images + a short vertical video. Within 10 days the campaign’s ROAS improved 30%. So yes — specs + variation + format breadth matter.
Final Thoughts
In the end, understanding and applying the correct Performance Max Google Ads specs is not just a checkbox exercise — it’s a performance lever. By providing strong, varied, correctly sized assets you give the algorithm the fuel it needs to run your campaign with maximum impact.
As I’ve learned in my own campaigns: Specs + variation + quality = reach + conversions. Neglect specs and you leave money on the table.
So go ahead — audit your asset groups, check that you’ve covered all formats, upload those extra variations, and let the AI do what it does best. Your campaigns will thank you.
Here are five frequently asked questions (and answers) about Performance Max Google Ads specs.
