The IAB Leaderboard Standard
The 728x90 leaderboard is one of the original IAB (Interactive Advertising Bureau) standard ad units and remains the most widely deployed banner format on the web. Introduced as part of the Universal Ad Package, this horizontal format is designed to sit at the top of a page, spanning most of the content width. Its wide, slim profile ensures high viewability without dominating the page layout. According to Google, the 728x90 leaderboard is consistently among the top-performing ad sizes in terms of available inventory and advertiser demand.
Optimal Page Placement and Viewability
Leaderboard ads perform best when placed above the fold, typically between the site header and the main content area. This position guarantees the ad is seen before a user scrolls, which directly impacts viewability metrics and CPM rates. Some publishers also use leaderboard units between content sections or at the bottom of articles as a secondary placement. Avoid placing them below long-scroll pages where viewability drops below the IAB threshold of 50% pixel visibility for at least one continuous second. Sticky leaderboard implementations that remain fixed at the top of the viewport have gained popularity for improving viewability scores.
Performance and File Size Considerations
For static leaderboard creatives, keep the file size under 150KB as recommended by IAB standards. Animated formats such as GIF or HTML5 should stay under 200KB for the initial load, with polite-load assets capped at 2MB. Google Ads enforces a maximum file size of 150KB for uploaded image ads. Use modern image formats like WebP where supported, and ensure text within the banner is legible at the actual display size since 90 pixels of height limits vertical space significantly. Always design with a clear call-to-action that is large enough to be clickable.
Design Best Practices
Given the constrained vertical space of just 90 pixels, effective leaderboard design requires a disciplined approach. Limit your message to a single headline, a brand logo, and one clear call-to-action button. Use high-contrast colors to separate the CTA from the background, and avoid small body text that becomes unreadable at scale. Ensure the ad has a visible border or distinct background color so it does not blend into the page. For responsive campaigns, consider pairing the 728x90 with a 320x50 mobile banner to cover both desktop and mobile placements within the same ad group.