In the world of display advertising, the Skyscraper (160×600) usually gets all the glory. But what happens when your website’s sidebar is too narrow for a wide ad, or you don’t want a massive banner dominating the entire vertical height of the page?
Enter the 120×240 Vertical Banner.
This compact vertical unit is the Swiss Army Knife of sidebar advertising. It is slim enough to fit into older or tighter website layouts, yet tall enough to display a product image, a headline, and a call-to-action without looking cramped. While it’s considered a “classic” size, it remains highly effective for advertisers who know how to use it strategically.
What is the 120×240 Vertical Banner?
The 120×240 ad is defined by the Interactive Advertising Bureau (IAB) as a “Vertical Banner.” It is essentially the younger sibling of the Skyscraper.
- Width: 120 pixels (fits very narrow columns)
- Height: 240 pixels (short enough to be less intrusive)
- Aspect Ratio: 1:2 (a perfect vertical rectangle)
Unlike the massive 160×600 Skyscraper, which requires a dedicated wide rail, the 120×240 can fit snugly into “left rail” navigation menus or crowded right-hand sidebars without breaking the site’s layout.
The “Ad Stacking” Strategy
One of the biggest advantages of the 120×240 format is the ability to use a strategy called Ad Stacking.
Because the unit is only 240 pixels tall, many publishers will stack two of them vertically in the same sidebar slot. This allows them to:
- Double the Inventory: Sell two ad spots in the space of one Skyscraper.
- Diversify Offers: Show two different products (e.g., “Web Hosting” on top and “Email Software” on the bottom) to see which one the user clicks.
- Combat Banner Blindness: Two smaller, distinct colorful boxes often catch the eye better than one long, monotonous gray tower.
Design Best Practices for 120×240
Designing for a narrow vertical space requires a different mindset than designing for a wide horizontal banner. You have to guide the user’s eye downward.
1. Top-to-Bottom Hierarchy
Since the ad is twice as tall as it is wide, stack your elements logically:
- Top: The Hook (Headline or Brand Logo)
- Middle: The Hero (Product Image or Key Benefit)
- Bottom: The Action (CTA Button)
2. Keep Copy Minimal
You only have 120 pixels of width. Long sentences will break into too many lines and become unreadable. Stick to punchy phrases of 2-4 words.
Bad: “Click here to find out how you can save money on insurance today.”
Good: “Save 50% on Insurance.”
3. High-Contrast Buttons
Because the ad is small, your Call-to-Action (CTA) button needs to pop. If your background is white, make the button bright orange or blue. Place it at the very bottom of the ad to act as the “period” at the end of the sentence.
When Should You Use This Size?
While the 300×250 Medium Rectangle is the king of content ads, the 120×240 Vertical Banner shines in specific scenarios:
| Scenario | Why 120×240 Wins |
| Narrow Sidebars | Many WordPress themes have sidebars that are only 150px wide. A 160px or 300px ad simply won’t fit. |
| Navigation Menus | It fits perfectly under a vertical navigation menu on the left side of a page. |
| Affiliate “Tiles” | Great for showcasing book covers, software boxes, or product packaging which are naturally vertical. |
Conclusion
The 120×240 Vertical Banner proves that you don’t need to take over the whole screen to make a sale. By fitting into tight spaces and offering a clean, vertical canvas for your message, it remains a reliable workhorse for affiliate marketers and smart publishers.
If you have a sidebar that looks empty but is too small for a big ad, the 120×240 is likely the perfect puzzle piece to monetize that space.