300×250 [MPU]

What is an MPU?

The 300×250 ad unit is an IAB standard ad unit with the dimensions of 300 pixels wide by 250 pixels tall.

This ad size is also known as an MPU in the UK, or Med Rec, MREC, or Medium Rectangle in the US.

This ad unit is commonly placed above the fold, and is often used as part of a multi-size ad slot with a 300×600 ad unit. It is generally the best performing ad size, as well as the most expensive/valuable.

The acronym MPU used in the UK is a confusing one as it has a different meaning depending on who you ask. It seems to be a mystery somehow lost to the ages, however the different meanings of the acronym reveal different things about this ad size, so are still useful:

  • Mid Page Unit” (or very occasionally “Mid Position Unit”) is the one you will hear most often. It is called this because these ads are often used in the middle of long articles – you scroll down and it breaks up an article, therefore keeping some value in having one long page instead of lots of shorter pages. Ads used like this will make/cost less money than their above the fold counterparts.
  • Multi Purpose Unit” is the second most common explanation of this acronym. It is probably the most accurate, as MPUs are used as the base for other “new” ad units that are launched – which are in fact just regular MPUs. The best examples of these “new” ad units are Video MPUs  which are just MPUs with videos in them (sometimes people charge/pay more for these, but there is no real reason to). Also many variations of Overlays are often spawned out of MPUs, with each ‘new’ ad unit pretending to be something new and special, but never actually quite getting there!
  • Message Plus Unit” is a rare explanation of this acronym, but one which still comes up. The idea behind it is that an MPU can deliver a message, plus something more. Like with Multi Purpose Unit, it is simply referring to how useful the MPU size and shape is to launch other units, or to contain videos.


What it looks like

Here is what a 300×250 looks like:

This MPU ad size is 300x250 pixels or a live example >


300×250 Advice for Site Owners

You can generally expect the highest CPM for this ad unit, along with the 728×90, especially if you position it above the fold.

This ad unit is often used as part of sponsorships, or else as a way to spawn other ad units, so should definitely be placed on every page.

It is often tempting to place several MPUs on a single page, however only the top most placement on any page will command a very high CPM. If you do put multiple MPUs on a page, make sure you are able to differentiate between them when placing ads so that you can sell guaranteed above the fold placements at a higher rate.

Tip: If an advertiser wants to spawn an overlay out of an MPU, charge them overlay prices + MPU prices for it.


300×250 Advice for Ad Buyers

The 300×250 is possibly the best advertising unit available, and is therefore the most expensive.

You should be able to embed videos into this ad unit without a problem – only the lowest rent site owners will charge you extra for this.

This unit is prevalent across all of the internet, and is often used multiple times on a page. If you are buying this ad unit then always check the positioning of it on the site you are buying from. Also make sure that if there are many 300×250’s on the same page, that you are getting what you pay for – only pay above the fold prices for above the fold placements. 300x250s further down the page will get much worse performance.



300x250 Definition


Find out more

Ad Size Guide

Author: Justin Driskill

Justin is the founder of The Online Advertising Guide and a freelance Digital Projects Manager.

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