Web Banner Sizes: Standard Ad Dimensions Cheat Sheet

Navigating Web Banner Sizes: The Essential Guide for Digital Marketers and Designers

When launching a digital advertising campaign, choosing the right creative dimensions can make the difference between a high-converting masterpiece and wasted ad spend. While automated tools and responsive ads have simplified modern workflows, understanding fixed web banner sizes remains a foundational skill for high-impact design.

Standardized by organizations like the Interactive Advertising Bureau (IAB), these dimensions ensure your visuals load cleanly across thousands of disparate publisher sites, mobile apps, and programmatic ad exchanges.

The “Fab Five” Core Display Sizes

You don’t need to design dozens of variations to capture a massive audience. Building a toolkit around the top five standard sizes will unlock roughly 80% of all available display inventory across the web.

| Dimensions (px) | Common Name | Typical Placement | Device | Strategy & Value |
| :— | :— | :— | :— | :— |
| 300 × 250 | Medium Rectangle | In-content, sidebars, below articles | Desktop & Mobile | The gold standard. High volume, highly versatile, and fits neatly into editorial layouts. |
| 728 × 90 | Leaderboard | Header, footer, above main content | Desktop | Classic top-of-page real estate; ideal for brand messaging and logos. |
| 160 × 600 | Wide Skyscraper | Right rail / sidebar (often sticky) | Desktop | Vertical format that stays in view longer as users scroll down. |
| 300 × 600 | Half-Page | Sidebar, embedded between content | Desktop | High-impact canvas; excellent for storytelling and immersive visuals. |
| 320 × 50 | Mobile Banner | Top or bottom of mobile screen | Mobile | Essential for smartphone traffic; features near-universal fill rates. |

Expanding Your Reach: High-Impact & Specialty Formats

If your budget allows or your campaign demands a premium look, extending your creative suite to include secondary sizes will grant access to exclusive publisher inventory.

• Large Rectangle (336 × 280): Slightly larger than the medium rectangle, it fits the exact same editorial spaces while giving designers a bit more breathing room for imagery and calls to action (CTAs).
• Billboard (970 × 250): A massive top-of-page canvas built for high-end brand campaigns and major product launches.
• Large Mobile Banner (320 × 100): Twice the height of a standard mobile banner, offering enhanced legibility and better click-through rates (CTRs) on smaller screens.

Best Practices for Designing Banner Ads That Convert

1. Keep File Sizes Lean: Most static display networks enforce a strict limit (typically 150 KB max for standard HTML5/image assets) to ensure lightning-fast page load times. Heavy ads get throttled or blocked entirely by modern browsers.
2. Prioritize Hierarchy: Every banner needs three elements: a clear company logo, a compelling value proposition, and a distinct button-style CTA (