Performance Max Asset Specs: Image Sizes, Character Limits and Requirements

A Performance Max asset group takes headlines up to 30 characters, long headlines and descriptions up to 90 characters, a business name up to 25 characters, and images in three ratios: 1.91:1 landscape at 1200 x 628, 1:1 square at 1200 x 1200, and 4:5 portrait at 960 x 1200. Images upload as JPG or PNG at 5 MB or less. To publish an asset group you need at least 3 headlines, 1 long headline, 2 descriptions, a landscape image, a square image, and a square logo. You can add up to 15 headlines, 5 long headlines, 5 descriptions, and 20 images.

Those are the numbers. The more useful question is which of them you should actually hit, because the minimum to publish and the amount that makes a campaign work are very different, and Google's own interface does a poor job of explaining the gap. Here is the whole spec sheet, followed by what to do with it.

Performance Max text asset specs

Character limits are counted the same way in every language, except that each character in double-width languages such as Japanese, Korean, and Chinese counts as two.

The requirement that catches people out is the short headline rule: at least one of your headlines has to be 15 characters or fewer. That slot exists because some placements have very little room, and if you skip it your asset group will keep flagging as incomplete no matter how many 29-character headlines you write. Your business name also has to match your domain or your legally verified business name, so it is not a place to put a tagline.

Performance Max image and logo specs

Images are capped at 20 per asset group across all ratios, upload as JPG or PNG, and must be 5 MB or smaller. Google recommends at least 4 landscape, 4 square, and 2 portrait images. The portrait ratio is technically optional and skipping it is one of the most common self-inflicted wounds in Performance Max, because the vertical placements on YouTube Shorts and Discover then have to be filled by cropping a landscape image, and an automatic crop of a wide image is where your product or your text ends up sliced in half.

Video is optional. If you supply none, Google assembles one from your images and text. Those auto-generated videos are usually serviceable and occasionally awful, and they will run whether or not you ever look at them, so it is worth opening the asset group and watching what got built in your name.

What is actually required to publish an asset group

The minimum set, for an asset group without a Merchant Center feed attached, is 3 headlines, 1 long headline, 2 descriptions, a business name, a final URL, one landscape image, one square image, and a square logo. If a Merchant Center feed is attached, the products themselves can carry the campaign and the asset requirements relax.

Meeting the minimum gets you a campaign that runs. It does not get you a campaign that works. Performance Max builds ads by mixing your assets into combinations across Search, Display, YouTube, Discover, Gmail, and Maps, so the number of distinct assets you supply is the number of experiments the system is able to run. Three headlines and two images is a very small experiment.

How many Performance Max assets should you actually add?

Fill the slots. In practice that means 11 to 15 headlines, 3 to 5 long headlines, 4 to 5 descriptions, and at least 4 landscape, 4 square, and 2 portrait images per asset group. This is the single clearest line between asset groups that perform and asset groups that quietly waste budget, and it is also the recommendation almost nobody follows, because producing 15 headlines and 10 images per asset group is real work.

Variety matters as much as volume. Fifteen headlines that reword the same benefit give the system fifteen versions of one idea. A useful headline set covers genuinely different angles: the outcome, the price or offer, the objection, the audience, the proof. If you are stuck for angles, it helps to write against the questions your customers actually ask rather than the features you want to talk about, the same discipline that makes responsive search ad copy work.

Do you need a separate asset set for every asset group?

Yes, and this is where the workload multiplies. An asset group is the Performance Max equivalent of an ad group: one theme, one final URL, one complete set of assets. Splitting a campaign into four themed asset groups is usually the right structural call, and it also means four complete asset sets rather than one. Most teams respond by making the second, third, and fourth asset groups thin copies of the first, which defeats the point of splitting them.

The honest constraint here is production cost, not strategy. Nobody chooses a worse campaign structure on purpose; they choose it because the designer has a queue. A generator that turns a landing page URL into the full set of ratios and copy variants removes that constraint, which is what our Performance Max asset generator is built for: paste the URL for each theme, get the landscape, square, and portrait images plus the headline and description variants, export, and upload.

What is a good Ad Strength for Performance Max?

Aim for Good or Excellent, and treat the score as a completeness checklist rather than a performance prediction. Ad Strength largely measures whether you filled the slots and varied the assets. It does not know whether your offer is compelling, and a Poor asset group can still convert while an Excellent one flops. What a Poor rating reliably tells you is that the system has too few combinations to test, which is a real problem worth fixing.

The quickest moves that lift it are adding the portrait image ratio, using all five long headline and description slots, adding the short headline of 15 characters or fewer, and adding sitelinks. Asset-level reporting in Performance Max is thin, mostly Low, Good, and Best labels rather than numbers, so teams that want a real answer about which creative earned the revenue export the conversion data and ask the data questions in plain English instead of waiting on the interface to tell them.

Common Performance Max asset mistakes

• One image stretched to three ratios. Uploading the same landscape file resized to square and portrait produces awkward crops and dead space. Compose each ratio properly, keeping the product and any text away from the edges.
• Text baked into the image. Overlay text gets cropped by automatic resizing and can look broken at small display sizes. Put the message in the headline and description fields, where the system can adapt it.
• Skipping the portrait ratio. The vertical placements are a large share of modern inventory, and leaving 4:5 empty hands your Shorts and Discover impressions to an automated crop.
• Ignoring the auto-generated video. It will run. Watch it before it does.
• One asset group for everything. A single group covering every product gives the model one blurred signal and no way to match creative to intent.
• Logo files that fail the minimum. A 128 x 128 logo is technically accepted and looks poor everywhere it appears. Upload 1200 x 1200.

A practical build order

Start with the final URL for the theme and write the long headlines first, because 90 characters forces you to state the actual value proposition. Cut those down into short headlines, making sure one lands at 15 characters or fewer. Write descriptions that add information rather than repeating the headline. Then build images in all three ratios from the same visual idea so the set looks like one campaign, and check each one at small size before uploading. Finally, add sitelinks and let Google generate the video, then review it.

If you also run standalone Display campaigns alongside Performance Max, the banner set is a different job with its own dimensions, covered in our guide to Google display ad sizes. And if the bottleneck is writing 15 headlines per theme rather than the images, the Google ad copy generator handles the text side inside Google's character limits.

Get the full asset set built from one URL

Performance Max rewards completeness, and completeness is a production problem before it is a strategy problem. Adscreator takes a product or landing page URL and returns the headlines, long headlines, and descriptions inside Google's character limits along with on-brand images rendered at 1200 x 628, 1200 x 1200, and 960 x 1200, so an asset group can be filled properly in one pass instead of over a week. Pricing is flat at $39 per month on Starter, or $29 per month billed yearly, with no credit meter, so building a complete set for every asset group costs the same as building one. Build your Performance Max assets and upload them to Google Ads yourself.