HTML5 Banner Ad Specs by Platform (2026 Guide)

HTML5 banner specifications aren’t one-size-fits-all

HTML5 banner specifications are rarely as simple as “keep it under 150 KB and make it 300×250.” The correct requirements depend on where the creative will be uploaded, how it will be served and which publishers or exchanges are included in the media plan.

Google Ads, Display & Video 360, Campaign Manager 360, Amazon DSP and AdRoll all handle HTML5 creative differently. A ZIP that uploads successfully to one platform can be rejected by another because of its file weight, animation length, clickTag implementation, folder structure or use of externally hosted assets.

This guide brings the main HTML5 display ad requirements together in one place. It is written for agency producers, designers, developers and media teams who need to brief, build, check and traffic display creative without a last-minute rejection delaying the campaign.

Quick answer: There is no universal HTML5 banner file-size limit. Google Ads uploaded HTML5 ads are generally limited to 150 KB, AdRoll also allows ZIP files up to 150 KB, Amazon DSP lists a 200 KB maximum for common desktop HTML placements, and Google Marketing Platform products support different upload and serving limits. Always check the platform, serving route, publisher requirements and media plan before production begins.

If you need a set built and checked against the correct platform requirements, Banner Squad provides HTML5 banner design and production across standard display, programmatic, rich media and interactive formats.

HTML5 banner specifications at a glance

The table below is a practical starting point, not a replacement for the final media specification. Publishers and exchanges can impose tighter limits than the main ad platform.

Platform	Typical delivery	Key file limit	Animation	Click handling	Important note
Google Ads	One HTML5 ZIP per creative	150 KB	Must stop within 30 seconds	Google-compatible exit/click handling	HTML5 upload access is subject to account eligibility
Display & Video 360	HTML5 ZIP or third-party served creative	Uploaded ZIP can contain up to 100 files; served download is capped at 5 MB	Up to 30 seconds for standard display	Click tag required	Publisher limits may be considerably lower
Campaign Manager 360	HTML5 ZIP or ADZ	Up to 100 files and 9.5 MB for an HTML5 asset bundle	Confirm against placement requirements	At least one click tag	Must load in an iframe; avoid nested ZIP files
Amazon DSP	Site-served or third-party iframe	200 KB HTML for common desktop display sizes	Confirm by format and placement	Confirm serving requirements	Static limits can be much lower, particularly on mobile
AdRoll	One ZIP per HTML5 ad	150 KB	Must stop within 30 seconds	clickTagvariable required	External-domain code references and CDN calls are not permitted
Adform, Flashtalking, Innovid, Celtra and Weborama	Platform-hosted or third-party served	Format, publisher and serving-route dependent	Placement dependent	Platform-specific exits or tags	Work from the campaign’s supplied specification rather than a generic limit

Producer’s rule: If a media plan says 150 KB, build to 150 KB even when the ad server technically accepts more. Successful upload does not guarantee acceptance across every publisher in the buy.

Why HTML5 banner specs vary

An HTML5 banner is effectively a small web page. Its ZIP can contain HTML, CSS, JavaScript, images, SVGs and fonts. When the ad loads, it may also request additional files, tracking pixels or dynamic content.

That creates several different measurements:

• Compressed ZIP size: the file uploaded to the platform.
• Initial load: everything required for the first visible frame.
• Polite load: additional assets loaded after the publisher page has completed its initial load.
• Total download size: all creative files downloaded when the ad serves.
• File or request count: the total number of files or external calls made by the creative.

These figures are not interchangeable. A platform may accept a relatively large ZIP but still restrict its total served download, initial load or number of HTTP requests. A publisher can then add another, tighter layer of requirements.

Before briefing production, confirm:

1. Which platform will host the creative?
2. Will the files be uploaded directly or served through a third-party tag?
3. Are there publisher-specific limits in the media plan?
4. Is the placement standard display, mobile, in-app, rich media or dynamic?
5. Are backup images, tracking pixels or multiple click exits required?

Standard HTML5 banner ad sizes

The required dimensions should always come from the approved media plan. However, these sizes appear regularly across display campaigns:

Size	Common name	Typical use
300×250	Medium rectangle	Desktop, mobile web and in-content placements
336×280	Large rectangle	Desktop and in-content placements
728×90	Leaderboard	Desktop headers and content breaks
160×600	Wide skyscraper	Desktop sidebars
300×600	Half page	High-impact desktop placements
970×250	Billboard	Premium desktop placements
320×50	Mobile leaderboard	Mobile web and app inventory
300×50	Mobile banner	Mobile web and selected network inventory
970×90	Super leaderboard	Premium desktop inventory

Producing only the 300×250 can restrict available inventory. Equally, automatically creating every possible size wastes budget if the media plan only includes five placements. Lock the final matrix before rollout and choose a master size that gives enough room to establish the animation, hierarchy and timing.

Banner Squad normally builds one animated HTML5 master for approval before adapting the campaign across the remaining sizes, versions and languages. That prevents an unapproved animation decision being repeated across an entire deliverables matrix.

Google Ads HTML5 specifications

Google Ads allows advertisers to upload HTML5 display ads as ZIP files, but uploaded HTML5 access is not automatically available to every account.

Main Google Ads requirements

• Supply one ZIP file for each creative size.
• Keep the uploaded HTML5 ad within the platform’s 150 KB file limit.
• Include the creative dimensions in the HTML metadata.
• Use supported local assets and secure URLs.
• Ensure animation stops within 30 seconds.
• Make the click area and exit behaviour compatible with Google Ads.
• Avoid unsupported techniques, intrusive behaviour and automatic audio.

Google states that accounts may need to meet eligibility requirements before HTML5 uploads are enabled, including a good policy and payment history and more than US$1,000 in lifetime spend. If HTML5 upload access is unavailable, responsive display ads or uploaded static assets may be needed instead.

Review Google’s current uploaded display ad specifications and HTML5 access requirements before delivery.

Banner Squad production note

A 150 KB cap is restrictive once a campaign includes large product photography, several fonts or complex animation. Optimisation should be considered during design, not left until export. Reusing assets, reducing unnecessary font weights, simplifying masks and compressing imagery early usually protects more visual quality than aggressively crushing the finished banner at the end.

For campaigns where speed and maximum compatibility matter more than motion, static banner production may be the more practical route.

Display & Video 360 HTML5 specifications

Display & Video 360 is frequently shortened to DV360. It supports uploaded HTML5 creatives, Campaign Manager 360 creatives and third-party ad tags, so the applicable requirement depends on the serving route.

Main DV360 requirements

• Uploaded HTML5 creatives should be packaged as ZIP files.
• A ZIP can contain up to 100 files.
• The HTML should declare the creative dimensions with an ad.size meta tag.
• A click tag must be included so the landing page can be configured and measured correctly.
• Standard display animation should not run for more than 30 seconds.
• Autoplay audio is prohibited; autoplay video must begin muted.
• Pop-ups and automatically launched surveys are prohibited.
• Total creative download is limited to 5 MB when served.
• A maximum of 100 HTTP calls is allowed per ad.

Google’s upload documentation notes that an HTML5 ZIP itself has no upload-size limit, while its serving guidelines cap the total downloaded creative files at 5 MB. This distinction is one reason conflicting “DV360 file limit” answers appear online. The publisher or exchange may still demand a much smaller creative, so the media brief remains the working specification.

Use Google’s current DV360 HTML5 creative requirements and HTML5 display guidelines as the primary technical references.

Banner Squad production note

Do not treat 5 MB as a target. It is a platform ceiling, not a recommended production weight. Lighter initial loads reduce the risk of publisher rejection and give the creative a better chance to render before the user scrolls past the placement.

Rich media, video and interaction can introduce different requirements. These campaigns should be scoped against the exact serving route and placement before development begins. See our approach to rich media display ads and interactive banner ads.

Campaign Manager 360 HTML5 specifications

Campaign Manager 360, commonly called CM360, is an ad server rather than a media-buying platform. Creative can be hosted in CM360 and then served into placements bought through DV360 or other media partners.

Main CM360 requirements

• Package each HTML5 creative as its own ZIP or ADZ file.
• Include no more than 100 files in the asset bundle.
• Keep the asset bundle within CM360’s 9.5 MB upload limit.
• Include a complete primary HTML document.
• Declare the dimensions using an ad.size meta tag.
• Include at least one readable click tag.
• Make sure the creative can load inside an iframe.
• Include only files referenced by the primary HTML document.
• Do not place ZIP files inside the creative ZIP.
• Avoid hard-coded landing-page URLs when the trafficker needs to control and report the final destination.

CM360 detects click tags during upload. Keeping the clickTag variable readable allows the trafficker to change the destination after upload and preserves click measurement. Google specifically advises against obscuring or minifying the clickTag itself, even if other production code is minified.

See Google’s documentation on preparing HTML5 assets for CM360 and CM360 display creative asset options.

Banner Squad production note

The CM360 upload allowance does not override the placement specification. A creative can be valid inside CM360 and still be too heavy for a publisher. The safest workflow is to collect both the ad-server requirements and the publisher specification before the master is built.

Amazon DSP display ad specifications

Amazon DSP supports display advertising across Amazon-owned properties and other sites around the web. Specifications vary between desktop, mobile, onsite, offsite and individual Amazon formats.

For common desktop display placements, Amazon currently lists:

Placement	Size	Maximum HTML weight	Maximum static weight
Medium rectangle	300×250	200 KB	40 KB in most markets
Leaderboard	728×90	200 KB	40 KB in most markets
Wide skyscraper	160×600	200 KB	40 KB in most markets
Large rectangle	300×600	200 KB	50 KB
Billboard	970×250	200 KB	Placement dependent

Amazon applies different static requirements to mobile placements. For example, its mobile leaderboard and mobile medium rectangle specifications include high-density image dimensions and considerably lower file-weight limits.

Always confirm whether the campaign is onsite or offsite, whether Amazon will host the creative, whether a third-party iframe will be used and whether high-density source files or safe zones are required.

Check Amazon’s current desktop and mobile web display specifications before production. Banner Squad also provides Amazon Ads creative production for campaigns spanning multiple placements and sizes.

Banner Squad production note

Do not assume the desktop layout can simply be scaled down for Amazon mobile. High-density image requirements, safe zones and smaller file limits can change how imagery, typography and calls to action need to be handled.

AdRoll HTML5 specifications

AdRoll accepts animated HTML5 ads for web inventory. Its requirements are comparatively clear and strict, making it important to build within the limit from the start.

Main AdRoll requirements

• Supply each HTML5 ad as a separate ZIP.
• Keep the complete ZIP to 150 KB or less.
• Place one complete HTML document at the root of the ZIP.
• Include all referenced code and assets inside the package.
• Ensure the ad can load in an iframe.
• Declare the creative size using an ad.size meta tag.
• Declare and use a clickTag variable.
• Stop animation within 30 seconds, including any loops.
• Load assets securely over HTTPS.
• Do not reference code on external domains.
• Do not use CDN calls, local storage or session storage.

AdRoll recommends 300×250, 300×600, 160×600, 970×250, 728×90 and 320×50, although final availability still depends on publisher inventory.

See AdRoll’s current animated HTML5 ad guidelines. Banner Squad also has a dedicated AdRoll creative production service.

Banner Squad production note

Because AdRoll requires commonly used JavaScript libraries to be included in the 150 KB package and does not allow CDN calls, the development approach matters. A heavyweight animation library can consume a large part of the allowance before images, fonts and creative assets are added.

What about Adform, Flashtalking, The Trade Desk, Innovid, Celtra and Weborama?

These platforms can support multiple creative types and serving workflows, including platform-built formats, uploaded assets, third-party tags, dynamic creative and publisher-specific rich media. That makes a single universal ZIP limit misleading.

For these campaigns, obtain the following before creative production starts:

• Platform and serving account
• Creative format or template name
• Publisher and placement list
• Initial and total load limits
• Polite-load allowance
• Approved libraries and external domains
• Exit or click-tracking implementation
• Dynamic feed requirements
• Impression and verification trackers
• Backup image requirements
• QA or platform certification process

If the campaign uses a managed rich-media platform such as Celtra, Innovid or Weborama, production may need to take place inside the platform rather than being delivered as a generic HTML5 ZIP. Banner Squad produces creative for Celtra, Innovid and Weborama workflows as well as standard uploaded display.

The files an HTML5 banner ZIP should contain

A conventional HTML5 display package contains:

• A primary index.html or other clearly identified HTML file
• CSS, either embedded or stored locally
• JavaScript required for animation and interaction
• Optimised JPG, PNG, GIF or SVG assets
• Local font files where permitted
• The ad.size metadata required by the platform
• The correct clickTag or platform-specific exit implementation

Avoid including:

• Source design files
• Unused images or font weights
• Nested ZIP files
• Hidden operating-system files
• Hard-coded URLs when the ad server must control the destination
• Unapproved external libraries or insecure HTTP assets
• Development files that are not referenced by the creative

Every extra asset creates more weight and another opportunity for a broken path. A clean package is easier to validate, traffic and troubleshoot.

Why HTML5 banner ads get rejected

Most rejections come down to a short list of production issues.

1. The creative exceeds the applicable file limit

Check whether the error refers to the ZIP, initial load, polite load or total download. Reducing only the ZIP compression may not solve a served-download issue.

2. The clickTag cannot be detected

The variable may be missing, incorrectly named, minified, hard-coded or disconnected from the clickable area.

3. The dimensions are missing or incorrect

The ad.size metadata must match the actual stage dimensions and the placement selected in the platform.

4. The animation runs for too long

The visible sequence may be under 30 seconds while a background loop, delayed timeline or repeated CTA animation continues indefinitely.

5. The ZIP structure is wrong

Common problems include an extra containing folder, several HTML entry files, assets outside the package, nested ZIP files or broken relative paths.

6. External assets are blocked

Fonts, libraries or images may work in a local preview but fail when the platform blocks external domains, insecure URLs or CDN calls.

7. The publisher has a tighter specification

Passing the ad-server validator does not guarantee that every exchange or direct publisher will accept the creative.

HTML5 banner QA checklist

Before delivery, check every size against the actual campaign specification:

• Dimensions match the media plan

• Filename follows the agreed naming convention

• ZIP opens without corruption

• Primary HTML file is present and loads correctly

• File weight is within the specified limit

• Initial, polite and total loads are within limits where applicable

• ad.size metadata is correct

• clickTag or exit event is detected and works

• Landing page opens in a new tab where required

• Animation stops within the allowed duration

• No automatic audio plays

• All assets load over HTTPS

• No unsupported external calls are made

• Copy, pricing, dates and legal lines match the approved source

• Logo and CTA remain legible at the smallest sizes

• Backup JPG or PNG is included when required

• Creative has been tested in the destination platform or approved validator

Banner Squad tests and packages every delivery so it is ready for trafficking. You can also use the Banner Squad HTML5 validator to carry out an initial technical check.

How AI-generated creative changes HTML5 production

AI tools can now generate campaign imagery, copy variants, layouts and motion concepts at speed. They can increase the number of assets entering production, but they do not remove platform requirements.

An AI-generated visual still needs to be compressed. Automatically generated layouts still need to be adapted intelligently across 300×250, 160×600 and 320×50. Every variation still needs approved copy, the right click behaviour, a valid ZIP and a final QA pass.

The production challenge is therefore shifting from “Can we make enough assets?” to “Can we control, adapt and validate all the assets we can now make?” For agency producers, a clear matrix, approved master and platform-specific QA process become more important as the number of versions increases.