Digitaland Advertising Blog

This cheat sheet is for ad ops teams, traffickers and producers who need the numbers before they brief a designer or upload a creative. It puts the HTML5 ad specs of CM360, DV360, Google Ads, The Trade Desk, Amazon, Yahoo, LiveIntent and direct publishers in one place. Every limit links to the platform’s own spec page, so you can check it yourself.

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Banner ad specs by platform: the cheat sheet

Here are the core limits, platform by platform. Each one comes from the platform’s own published spec, linked in the sections below.

Animation length and border rules vary just as much:

For the pixel sizes themselves, see our IAB standard banner sizes guide.

Display ad file size limits: initial load, subload and ZIP

A weight limit can mean three different things. Check which one a spec uses before you build.

• Initial load is everything the ad requests to draw its first frame, before the page finishes loading.
• Subload is what the ad may load after the page’s load event.
• ZIP size is the upload package. It says little about how heavy the ad is in the browser.

The IAB Tech Lab’s New Standard Ad Unit Portfolio defines these terms. It measures weight after gzip compression and caps the initial load at 10 file requests. It also says to use the initial-load figure for static and backup images.

IAB also asks for no more than 30% CPU load per ad and no animation past 15 seconds. If your banner runs heavy, our 5 tips to reduce HTML5 banner size will help.

Google CM360 and DV360 creative specs

Google’s two ad platforms are generous on weight and strict on packaging.

CM360’s HTML5 page sets these rules for the ZIP:

• Up to 100 files.
• Allowed types: HTML, JS, CSS, images (JPG, GIF, PNG, SVG), JSON, XML and web fonts.
• No local storage or session storage.
• No percent sign in any file name.
• No backup image inside the ZIP.

DV360 also allows 100 files per ZIP. It sets no ZIP size limit, but asks you to keep files small to meet publisher limits. File names must stay at 200 characters or fewer. Backups are optional and go in their own upload field. Without one, DV360 serves a blank image. CM360 serves nothing. Our HTML5 backup image guide covers both cases.

Google Ads HTML5 and image ad specs

Google Ads is the tightest Google platform. Not every account can upload HTML5 at all.

• Eligibility: account open more than 90 days, more than $9,000 lifetime spend, and a good policy record.
• HTML5 ZIP: 600 KB or smaller, with no more than 40 files.
• Assets: referenced by relative path inside the ZIP. Only Google Fonts and a few Google-hosted libraries may load from outside.
• Size tag: an ad.size meta tag in the head.
• Image and GIF ads: 150 KB maximum. GIF animation must stop after 30 seconds and run slower than 5 fps.

Accounts that miss the bar run image or GIF ads instead. That makes a well-made static set part of the deliverable, not an extra. Our guide to static vs dynamic banners explains when each one fits.

The Trade Desk HTML5 ad specs

The Trade Desk’s creative specifications (PDF, March 2025) are the most detailed on this list. Its hosted HTML5 system “requires that you upload a static backup image.”

Two details catch teams out. Click tag names are case-sensitive, and the platform defaults to clickTAG, not clickTag. And the primary HTML file must sit at the root of the ZIP, not inside a folder.

Amazon Ads: the strictest weight limits

Amazon’s technical guidelines for third-party HTML ads cover non-expanding desktop placements on Amazon’s own sites. They are short and strict.

• Weight: 200 KB for the HTML ad in 300×250, 728×90, 160×600 and 300×600.
• Static files: 40 KB, or 50 KB for 300×600.
• Animation: up to 3 loops, 15 seconds maximum.
• Requests: no more than 10 HTTPS requests.
• CPU: no more than 30%.
• Code: minified and concatenated, no console statements, no Flexbox, and requestAnimationFrame for JavaScript animation.
• Fallback: a static backup in a noscript tag, plus a static image when the ad fails to load.

The no-Flexbox rule surprises modern developers. Check it before the build starts, not at QA.

Your HTML5 campaign ZIP goes in. Backup images, GIFs and MP4s come out. Every size. Every platform. Free. JPGGIFMP4 Try it free

Yahoo and publisher-direct specs

Yahoo’s HTML5 guidelines push weight limits down to each ad format page. Two rules apply to every format:

• Keep everything loaded before a click or tap under 4 MB.
• Keep the clickTag readable, not minified, so reviewers can check it.

Site-served Yahoo ads must be self-contained, with every font and library in the ZIP. If you add a backup, it goes inside the ZIP. Yahoo also warns that Chrome’s Heavy Ad Intervention may unload ads that use too much network or CPU.

Direct publisher specs are smaller and more varied. A few examples:

• The Seattle Times takes a JPG of 15–60 KB or an HTML5 file of 200 KB per size, with a border on white backgrounds.
• Are Media asks for a 40 KB backup on rich units and a 1px solid border on white creative.
• Advance Ohio’s 2025 spec lists a 60 KB backup image.

Always ask for the publisher’s current spec sheet. Our rich media creative specs guide covers the larger formats.

Email banner specs: static and GIF only

Email can’t run JavaScript, so HTML5 is out. LiveIntent (Zeta Global) runs ads inside email newsletters. It accepts only PNG, JPG or GIF.

• Weight: 250 KB for static, 4 MB for GIF.
• First frame: the GIF must show the complete ad in frame one.
• Timing: 8 seconds per loop at 5 fps, up to 3 loops. Animation stops after 30 seconds.
• Border: at least 1px on white or gray backgrounds.
• Required sizes: 300×250, 970×250 and 970×550, plus larger square and portrait sizes.

So a display campaign that adds email needs a second set of files. Our free tool turns an HTML5 banner ZIP into backup images, GIFs and MP4s, so the email set comes from the finished banner. For email rendering issues, see our guide to dark mode in email.

7 banner spec mistakes that get creatives rejected

1. Checking the ZIP instead of the initial load. A small ZIP can still load too much before the page does.
2. Too many files at load. IAB and The Trade Desk cap the initial load at 10 files. Amazon caps HTTPS requests at 10.
3. The wrong click tag case. The Trade Desk defaults to clickTAG. Amazon asks for clickTag.
4. Animation past 15 seconds. IAB, The Trade Desk and Amazon all stop there.
5. No border on a white ad. The Trade Desk, LiveIntent and publishers like Are Media ask for one.
6. Browser storage in the code. CM360 and DV360 reject HTML5 that uses local or session storage. Amazon bans it too.
7. The backup in the wrong place. Google wants it beside the ZIP. Yahoo wants it inside.

How to build one banner set that passes every spec

The fastest route is to design once, to the strictest spec on the plan. Here is the order our producers follow:

1. List every destination first. Get the media plan before design starts, including email and direct publishers.
2. Set the weight budget to the lowest limit. For a 300×250, IAB’s 150 KB initial load also clears Amazon’s 200 KB and The Trade Desk’s 300 KB.
3. Keep the first load to 10 files or fewer. Sprite sheets help. Load the rest after the page’s load event.
4. Cap animation at 15 seconds. End on a frame that holds the full message.
5. Add the basics to every file. An ad.size meta tag, a readable click tag in the right case, no browser storage.
6. Export the statics. A backup per size at 40 KB or less, and GIFs for email and Google Ads.
7. Package per destination. Backups beside the ZIP for Google and The Trade Desk, inside it for Yahoo.

Our designers check every static at 100% so fine print stays readable after compression. For the full workflow, see how a PSD becomes a finished HTML5 banner. If you’d rather hand the specs to a studio, here’s how to outsource HTML5 banner production.

Frequently asked questions

Sources

• Google CM360: HTML5 file requirements
• Google CM360: Image and HTML5 assets
• Google DV360: HTML5 creatives
• Google Ads: display ad requirements
• The Trade Desk Creative Specifications (PDF, March 2025)
• Amazon Ads technical guidelines
• Yahoo HTML5 guidelines
• LiveIntent ad specs and creative requirements
• IAB Tech Lab New Standard Ad Unit Portfolio (PDF, 2017)
• The Seattle Times creative guidelines
• Are Media digital advertising guidelines
• Advance Ohio 2025 digital ad specs (PDF)