336×280 – Large Rectangle

What is a 336×280?

336×280 ads are also known as large Rectangles (or LREC). As the name implies, it is essentially the big brother to a 300×250 (or Medium Rectangle) ad unit. An LREC is 336 pixels wide by 280 pixels tall. The 336×280 ad unit was delisted by the IAB in 2011, but has been seeing an increase in usage since 2022.

The 336×280 ad can be run in its own ad slot but is more commonly set up as a multi-sized ad slot with a 300×250.

The 336×280 large rectangle is a highly successful ad unit on AdSense, both in terms of performance and the eCPM it commands. However, it is not very common on other ad networks, which is why the IAB delisted it in 2011 in favour of the 300×250 ad unit.

An LREC is usually placed on the side of content, in the same place an MPU would be. When no Large Rectangle is available to deliver, AdSense will show a centred 300×250 instead.

What it looks like

The LREC dimensions are 336 x 280 pixels. Below is a live example of this ad unit.
Note: For technical reasons, the live ad may not always load; instead, a backup image will show.

336×280 Advice for Site Owners

If you use AdSense as your ad network, you can expect a high RPM for 336×280 ads. If no 336x280s are available, a 300×250 will appear, making it a useful ad space. It is worth pursuing if your site looks good with this ad size.

This ad unit is rarely used outside of AdSense. This means if you sell ads to multiple ad networks, this ad size might cause problems. The best way to manage this is to ensure your 336×280 ad slot is used as a multi-sized ad slot with a 300×250 so you don’t have to worry about editing your site.

This ad unit has the same aspect ratio as the very popular 300×250. It wouldn’t be surprising if it made a comeback in the coming years, as increasing screen resolutions will once again make old sizes seem smaller.

336×280 Advice for Ad Buyers

This ad unit is usually very successful, so it should be considered for an ad buy. It is often reasonably priced as there is sometimes less competition for this ad size. However, in many cases, you can expect to pay the same CPM or CPC as an MPU, as that is what you will ultimately be competing with.

This ad size has the same aspect ratio as a 300×250, so it should be very easy to design. If you are already creating an MPU, you can scale it up, making the extra ad unit’s costs minimal.

Top Tip: A 336×280 is essentially a large MPU, so it should be used for interactive or video ads to get the most out of it.

Summary

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