The Ultimate Guide to Standard Web Banner Sizes: Which Dimensions Drive Real Results?

Whether you are designing a high-converting display campaign for Google Ads, building out programmatic placements, or preparing assets for a client, getting your dimensions right is the difference between a high-performing ad and wasted ad spend.

When your ad doesn’t fit the container, platforms stretch, crop, or reject it entirely. To ensure your creative assets look sharp and professional everywhere they appear, let’s break down the Interactive Advertising Bureau (IAB) standard web banner sizes that dominate digital marketing today.

The Big Four: The Highest-Performing Ad Sizes

If you are working with a tight budget or limited design resources, you don’t need to build every single dimension under the sun. Focusing on the four most widely used and highest-inventory sizes will cover the vast majority of publisher sites:

1. Medium Rectangle (300 x 250 px)
   • Best For: Embedded within content paragraphs, sidebars, and mobile web pages.
   • Why it works: It offers the highest inventory across the web because it integrates seamlessly into editorial layouts without disrupting the user experience.
2. Leaderboard (728 x 90 px)
   • Best For: The very top of desktop websites (header banners).
   • Why it works: It’s prime real estate. Users see it instantly upon landing on a page, making it ideal for brand awareness.
3. Large Rectangle (336 x 280 px)
   • Best For: Text-heavy articles and content-rich sidebars.
   • Why it works: Slightly larger than the standard medium rectangle, giving designers more room for compelling imagery and clear calls-to-action (CTAs).
4. Half Page / Skyscraper (300 x 600 px)
   • Best For: Sticky sidebars and high-impact visual storytelling.
   • Why it works: Often called a “half-page” ad because of its massive surface area, it commands attention and yields higher engagement rates than smaller banners.

Comprehensive Cheat Sheet: Standard Banner Dimensions

To make planning your next campaign effortless, here is a breakdown of the standard desktop and mobile banner sizes categorized by shape:

| Ad Type | Dimensions (Width x Height in Pixels) | Best Placement / Use Case |
| :— | :— | :— |
| Leaderboard | 728 x 90 px | Top of desktop pages / headers |
| Large Leaderboard | 970 x 90 px | Premium top-of-page brand showcases |
| Billboard | 970 x 250 px | High-impact homepage takeovers |
| Medium Rectangle | 300 x 250 px | In-content, sidebars, universal fit |
| Large Rectangle | 336 x 280 px | Inside articles, high engagement |
| Half Page | 300 x 600 px | Sidebars, rich media, high impact |
| Wide Skyscraper | 160 x 600 px | Vertical desktop sidebars |
| Mobile Leaderboard | 320 x 50 px | Bottom or top of mobile web viewports |
| Large Mobile Banner | 320 x 100 px | High-visibility mobile sticky banners |

Key Best Practices for Banner Design

Knowing the dimensions is only half the battle. To turn impressions into clicks, keep these core design principles in mind:

• Prioritize High-Contrast CTAs: Your button or call-to-action (“Shop Now”, “Learn More”) should stand out immediately against the background.
• Keep Copy Minimal: Users scroll fast. Aim for a punchy headline and clear value proposition that can be read in under two seconds.
• Optimize File Size: Keep your GIFs, HTML5 files, or static images lightweight (ideally under 150KB) to ensure rapid loading times and avoid ad-network throttling.
• Design for Retina Displays: Always export your raster assets at 2x resolution so they remain crystal-clear on high-density screens.