300x600

300x600 refers to a digital advertising banner size of 300 pixels in width and 600 pixels in height. It is part of the IAB standard ad unit portfolio and is commonly known as the half-page ad due to its vertical, tall format. In desktop web contexts, it is typically placed in sidebars or within content rails where space allows a tall creative without occupying the full width of the page.

Creatives for 300x600 can be static images (JPEG, PNG), animated GIFs, or rich media and HTML5 banners. The format supports diverse interactions, including expandable or interactive elements, depending on the publisher's capabilities and ad server.

While it offers strong visual presence and higher impact than smaller banners, its usage is less universal on mobile devices because of limited screen width, and it can affect layout or load times on pages with limited bandwidth. Advertisers sometimes pair 300x600 with other sizes in a campaign to maximize reach and viewability through responsive ad strategies.

Programmatic publishers and ad networks commonly support 300x600 within the IAB standard set, and it is available through major ad servers such as Google Ad Manager. Designers should consider safe zones and non-interference with site navigation, as the tall banner can occlude content on small viewports.

See also: IAB standard ad unit portfolio, common desktop ad sizes.