Banner ad sizes that earn their place on the display network

The sizes worth making first

Size	Name	Where it appears
300 x 250	Medium rectangle	Inside article content and sidebars. The most widely used size on the network.
336 x 280	Large rectangle	Wider content columns, where the medium rectangle looks undersized.
728 x 90	Leaderboard	Across the top of desktop pages.
320 x 50	Mobile banner	The standard mobile slot. Small, so the message has to be one line.
300 x 600	Half page	Desktop sidebars. Large enough to carry an offer and a form.
160 x 600	Wide skyscraper	Narrower sidebars. Almost always needs a vertical layout, not a squeezed one.

Why six beats twenty

Every size needs its own layout. A leaderboard is a single line of copy beside a logo; a half page is a headline, a supporting line, a button and an image. Shrinking one design into every slot produces text nobody can read and buttons nobody can hit.

Six well built sizes cover the placements that carry most impressions. Add the rest only if the placement report shows a slot you are missing, which is a decision made from data rather than from a size list.

What the creative has to do in one second

• Say what the offer is. Not the brand name alone.
• Carry one action, with a button that looks like a button.
• Keep the logo small. The viewer already knows where they are.
• Use contrast that survives a low quality placement beside a busy article.
• Avoid text baked in at a size that disappears on a phone.

How to judge whether display is working

Display is usually the weakest channel on a last click basis and a useful one on a first touch basis. Judge it on view through enquiries and on the lift in branded search, not on the click through rate alone. If a placement never produces either, block it and move the budget.

That is the same standard we apply in a card: every channel has to show what it contributed, and a channel that cannot is a cost rather than an investment.