Ad sizes are referred to by their size in pixels, with the width first, followed by the height and using the word “by” to connect them. For example, 300×250 is said as “300 by 250”.

If you have custom ad unit sizes that are unique to your site, feel free to keep using them (as stand alone or within a multi-size ad unit), as they’re likely key products in your direct sales strategy. Though for programmatic, you’ll see the highest yield by sticking to industry standard sizes.

Medium Rectangle – 300×250

This size is the most popular, accounting for 40% of display ads served across the web. This size is most often found in the sidebar on desktop or inline on mobile.

Leaderboard – 728×90

With a frequency of 25%, this size is one of the most recognizable. This size is friendly for use across desktop and tablet and is a great option for within article content between paragraphs.

Wide Skyscraper – 160×600

Tying with the leaderboard for second most popular, this ad size also accounts for 25%. It’s most likely to be seen in the sidebar.

Halfpage – 300×600

This size is often coupled in an ad unit with a 300×250. While you will see greater a fill rate from 300×250 (as 300x600s only account for 5% of ads on the web), you will see higher CPMs from 300×600 due to its real estate and ability to be “high impact”.

Super Leaderboard – 970×90

This size is usually found at the top of the page and makes up 5% of ads on the web. Because it has the same height as the more popular 728×90, it’s recommended that this size be included as a flex option for ad units that appear above the fold on desktop in order comply with content shift standards.

Billboard – 970×250

While only 1% of frequency on the web, this large, high impact size yields high CPM and is recommended to include as a flexible option with 728×90 and 970×90.

Mobile Banner – 320×50

Designating ad space on mobile is challenging, so in order to create a non-invasive experience for the user while also giving publishers a better opportunity to sell mobile ad space — the mobile sticky footer arrived. 320×50 is the recommended size for the mobile sticky footer, but should be a size that’s accepted within nearly all ad units, as it represents 12% of advertising demand.

Recommended Flex Groups

In order to maximize fill rate, it is recommended that ad units be set up to accept multiple sizes. Your ad server will then deliver whichever size is most needed to meet ad campaign goals. For example, within an ad unit, you may see a 300×250 ad creative, but when you navigate to another page or refresh the current page, a 300×600 may appear in that same ad unit. Your ad server will make the best decision for each individual impression based on delivery goals.

By default, Newspack detects the screen size of the user and requests the appropriate size ad from your ad server. For example, if you set up an ad unit to accept 300×250, 300×600, and 320×50, it will show a 300×250 or 300×600 for desktop users and 300×250 or 320×50 for mobile users.

When an ad unit can accept more than one size, it is called a multi-size ad unit or flexible ad unit.

Here are a few recommended combinations:

Sidebar units: 300×250, 300×600, 160×600, 320×50

Between blocks on the homepage: 728×90, 970×90, 970×250, 320×50

Within article content with a sidebar: 728×90, 300×250, 320×50

Within article content with no sidebar: 728×90, 970×90, 970×250, 320×50