If you’re new to display advertising, you may not know that each ad-platform supports different banner sizes. This article aims to make you familiar with the most common ad dimensions of the most used ad-platform. We will show you examples of ad sizes, how to maximize their effectiveness and explain which ones you should use for the highest ROI.

This article is part of a series of articles for founders, marketers, and anyone interested in the display advertising world. If you need to market your product or service you've come to the right place.

You can read the previous article of this series "Why you Should Invest in Search Engine Advertising". In this article we went through the benefits of including SEA (Search Engine Advertising) into your advertising strategy.

Does banner format really matter?

To the end-user it may look like all Ad formats are similar, the truth is that not all of them are going to meet the same goals & expectations. Different sizes require different strategies, text, creativity, and call to action!

In our first article in this series, we've covered how modern advertising works and the lifecycle of an advertising campaign.

Let’s analyze as an example a famous tech-news website like TechCrunch. Their website supports only 3 types of IAB banner formats!

TechCrunch available Ad units
TechCrunch available Ad units
  • On desktop & tablets:
    - IAB – 300×250
    - IAB – 728×90 (desktop only)
  • On mobile:
    - IAB – 300×250
    - IAB – 320×50 (mobile only)

Choosing the wrong format could effectively limit your campaigns’ reach. Using uncommon ad formats not only could result in your ads being disapproved but could also mean they are distributed inefficiently in the ad auction phase.

Most savvy advertisers will focus their efforts on 4 to 5 banner sizes only, and will also run a lot of A/B tests to find their best banner combinations.

Did you know? Display Advertising (with IAB formats) is the most commonly used strategy for “brand awareness”, as the CTR and CPM are extremely low.

You probably will have to test most banner formats to optimize your ROAS in your business vertical. As your marketing expenses grow and you acquire a better understanding of banner formats that achieve your goals, you will start cutting off underperforming formats.

After researching this topic we noticed that no major ad-networks gives data on banner performances.

Ads placed above the fold will almost always outperform creatives placed below, so keep that in mind when buying ad space.

However, a global trend appears after analyzing 3rd party data sources on banner advertising. Here you can find the list of popular ad formats you should strongly consider for your business.

Medium Rectangle (300×250)

Known as “Medium Rectangle” this banner format is generally the best-performing ad size, most widely-used, and the most expensive (because valuable).This banner size has over 40% of global inventory on any given Ad Network and is by far the most valuable weapon in your display advertising strategy.

One of the reasons for its popularity is its ability to perform well on both desktop and mobile.

300×250 - Banner generated on Abyssale.com
300×250 - Banner generated on Abyssale.com

Leaderboard (728×90)

Also known as “Horizontal Banner”, it is amongst the best-performing ad slots (2nd most used among global ad inventory).

Likely to be amongst the most expensive ad formats available (with the 300x250), but generally worth it due to its high performance.Usually displayed at the top of websites, it can also be found between articles on news, media, and entertainment platforms. It is most of the time one of the first elements a user will see, this explains it’s higher cost.

728×90 - Banner generated on Abyssale.com
728×90 - Banner generated on Abyssale.com

Wide Skyscraper (160×600)

The 160×600 ad size is mostly placed by publishers below the fold and on the side of websites.

This is why it won’t perform as well as the 300×250 or 728×90 ad formats. You can generally expect a reasonably low CPM for this ad unit on most ad networks.

160×600 - Banner generated on Abyssale.com
160×600 - Banner generated on Abyssale.com

Half Page Unit (300×600)

The 300×600 Half Page Unit  (or HPU) is a highly successful banner format in terms of performance. However, it is not yet part of the standard Ad list because of the limited inventory available.

This banner format should be considered since it is one of the best performings when used well. It has, however, an expensive CPM compared to other ad units.

It can usually be viewed on entertainment and/or news websites. Widely used by luxury brands, GAFA’s, and other huge brands because of its size that allows capturing audience attention.

300×600 - Banner generated on Abyssale.com
300×600 - Banner generated on Abyssale.com

Mobile Leaderboard (320×50)

Known as a ”Mobile Leaderboard”, or “Smartphone Leaderboard” this ad unit is one of the mobile-specific ad formats available.

Very effective if used right, the Mobile Leaderboard often doesn’t cost much. This ad unit also has plenty of inventory available.

Since the real estate is very small you’ll have to make sure your message is concise to convey and ensure you’re using simple & clear graphics.

Large Mobile Banner (320×100)

Also known as the "Large Mobile Banner" it is the big brother of the 320x50 ad unit. Mobile-specific banners are rather small, but the 320x100 is the largest available mobile-specific ad format available.

It yields better performance than other mobile banner sizes. However, its popularity comes with a price! You can expect a higher CPM than a 320x50 ad unit, this is why you should test both formats if you're targeting mobile devices and see what is your ROAS to understand if you should keep both of them in rotation.

To get the most out of any mobile-specific banner you have to make the best use of the small space available to you. This means having a very concise message and call to action, which can fit in the space.

What's next?

Hopefully, this article helped you in understanding how different banner formats work, how you should use each format to target your audience based on budget device and ROI.

  • A key takeaway from this article is that the most popular choices are not necessarily the best choices for you.
  • Another takeaway is the importance of A/B testing banner formats, and not only focusing on testing different creative content: a change in format, could show you improvements in ROAS (Return On Ad Spend) very quickly while A/B testing.

Wouldn’t it be amazing if there was a platform that could help you create variations of banners, format, design and call to actions - so that you could A/B test quickly what works best for you? 💚😉

In the next article we’re going to do a deep dive into banner design for you to create an efficient and measurable display ad campaign.

Anatomy of a Relevant Banner Design
As you are probably aware consistent branding is one of the most important elements of advertising. Brand consistency allows you to create a sense of belonging. As your brand grows more people will recognize it, consistency in branding allows your brand to be ...