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Ad Size Preview Tool

Designers and developers often forget the exact proportions of standard ad units. Use this tool to visualize common IAB formats at actual pixel dimensions. Preview before you design or implement.

Standard Mobile Social Video

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Preview Mode
Canvas Area: Auto 300 x 250
300 x 250

? How to Use Ad Size Previewer

  • Step 1: Browse Available Sizes - View the complete list of IAB standard ad sizes with their names and dimensions.
  • Step 2: Click to Preview - Select any ad size to see a preview box at actual pixel dimensions on your screen.
  • Step 3: Check Proportions - Use the preview to understand how the ad unit will look relative to your content layout.
  • Step 4: View Device Category - Note whether the size is for desktop, mobile, or both. Implement accordingly in your responsive design.
  • Step 5: Compare Multiple Sizes - Select different sizes to compare which fits best in your available ad slots.
  • Step 6: Use for Design Reference - Designers can use actual dimensions when creating ad space mockups or placeholder graphics.

Frequently Asked Questions

What is the most popular ad size?

The 300x250 Medium Rectangle is widely considered the most popular and versatile ad size. It works on both desktop and mobile, fits naturally within content, and has the highest advertiser demand. Nearly every ad campaign includes 300x250 creatives.

What are IAB standard ad sizes?

The Interactive Advertising Bureau (IAB) defines standard ad dimensions for the digital advertising industry. Standard sizes ensure ads display correctly across all websites. Popular IAB sizes: 300x250, 728x90, 160x600, 300x600, 320x50. Stick to standards for best fill rates.

Do I need all ad sizes on my website?

No! Focus on 3-5 high-performing sizes. Essential sizes: 300x250 (must-have), 336x280 (higher CPM), 300x600 (desktop sidebar). Mobile: 320x50 or 320x100. Too many sizes can slow page load without proportional revenue increase.

What's the difference between 300x250 and 336x280?

336x280 (Large Rectangle) is slightly bigger than 300x250 (Medium Rectangle). The larger canvas allows better creative display, often resulting in 5-15% higher CPM. Use 336x280 where space permits. Both have excellent advertiser demand.

Which ad sizes work best in mobile?

Top mobile sizes: 300x250 (universal, in-content), 320x50 (mobile leaderboard, header/footer), 320x100 (large mobile banner, higher CPM), 336x280 (if screen width allows). Avoid desktop-only sizes like 728x90 or 970x250 on mobile layouts.

How do I create responsive ad slots?

Options: 1) Use ad network auto-ads (automatically selects sizes). 2) Implement responsive ad units that adjust to container width. 3) Serve different ad sizes based on viewport using CSS media queries. 4) Use SDK/JS to detect screen size before requesting ads.