Topscroll
A screen-high ad above the site’s header as the page opens. The reader scrolls past it into the page.
Guide · updated November 2026
Every standard web banner size in one place: the IAB and Google display sizes, which ones to make first, mobile and desktop, what an HTML5 banner may weigh, and the high impact formats Nordic news sites sell.
The banners here are one live sample, Kestrel, a made-up brand, shown at each size. Its photos were made with AI.
Each box is drawn at the same scale, so you can see how the sizes compare. Pick a screen to see which sizes run there.
The sizes most sites have slots for. If you only make a few, make these first.
Sizes are in CSS pixels, width × height. Names vary from site to site; the size is what the ad slot asks for.
| Format | Size | Screen | Where it usually sits |
|---|---|---|---|
| Medium rectangle (MPU) | 300 × 250 | Desktop and mobile | In the article, in the sidebar, between posts in a feed |
| Large rectangle | 336 × 280 | Desktop | In the article text |
| Leaderboard | 728 × 90 | Desktop and tablet | Above the page header, or between sections |
| Large leaderboard | 970 × 90 | Desktop | Across the top of the page |
| Billboard | 970 × 250 | Desktop | Across the top of the page, above the content |
| Half page | 300 × 600 | Desktop | In the sidebar, often sticky as you scroll |
| Wide skyscraper | 160 × 600 | Desktop | In the sidebar |
| Skyscraper | 120 × 600 | Desktop | In the sidebar; an older size, still sold |
| Portrait | 300 × 1050 | Desktop | In the sidebar, the full height of a screen |
| Banner | 468 × 60 | Desktop | In the content; an older size, still sold |
| Square | 250 × 250 | Desktop and mobile | In the sidebar or the content |
| Small square | 200 × 200 | Desktop and mobile | In the sidebar or the content |
| Mobile leaderboard | 320 × 50 | Mobile | Across the top or the foot of the screen |
| Large mobile banner | 320 × 100 | Mobile | Across the screen, in the content |
| Mobile fullscreen | 320 × 480 | Mobile | Over the page, between page views |
In 2017 the IAB’s New Ad Portfolio moved its guidelines towards ads defined by aspect ratio rather than fixed pixels. The fixed sizes above are still what most ad slots and rate cards ask for.
Many readers are on a phone, so plan for both. Phones are about 360 to 430 CSS pixels wide, and mobile sizes are 320 wide, so they fit the narrowest common phones with room to spare.
Swedish and Norwegian sites sell some sizes of their own, wider on desktop and taller on phones. MAiKE’s standard set is built from them.
MAiKE’s standard set also has 160 × 600, 300 × 600 and a large 980 × 600.
An HTML5 banner is a small web page shown in a frame in the ad slot: HTML, CSS, images, fonts and sometimes a little JavaScript. Most sites and networks ask for it to meet a spec. These are the parts that usually come up.
Each site and ad network sets its own limit. Many ask for a first load of around 150 KB, with more allowed once the page has loaded. Images and fonts are usually the heaviest part.
A click goes through a clickTag: the ad server passes in the landing page’s address, so it can count the click and change the address without a new banner.
Specs often limit how long a banner animates and how many times it loops. Many end on a still frame that carries the brand and the message.
Phones and many laptops have high-density screens, so pictures are made at about twice the banner’s size, then compressed to stay light.
A 728 × 90 and a 300 × 600 are different shapes, not the same ad scaled. Each size needs its own layout, with text big enough to read at that size.
Before you build, ask for the site’s spec: sizes, weight, animation and how it wants clicks tracked.
Nordic news sites also sell ads that fill the screen as you scroll. They aren’t a fixed box: they’re built at the size of a screen, 1920 × 1080 on a desktop and 414 × 896 on a phone, and many publishers run them with High Impact JS, which hands the ad the reader’s scroll.
A screen-high ad above the site’s header as the page opens. The reader scrolls past it into the page.
A window in the article. As the reader scrolls past, it shows a fullscreen ad behind the page.
A slot two screens tall. The ad holds the screen for a screen of scrolling, then the page moves on.
A fullscreen ad over the site as it opens, before the reader goes on to the page.
MAiKE builds all four, at a real screen size, with High Impact JS support. See a midscroll on a sample news page →
How MAiKE does it
MAiKE is an AI banner maker from Madington. Give it the page you advertise and the formats you need, and it builds the HTML5 banner in each of them.
One Kestrel sample, four shapes, each with its own layout. Kestrel is a made-up brand; its photos were made with AI.
The 300 × 250 medium rectangle. It fits in an article or a sidebar on a desktop and in the feed on a phone, so almost every site has a slot for it.
728 × 90 on a desktop. The mobile leaderboard is 320 × 50, and the large leaderboard 970 × 90.
320 × 50 and 320 × 100 across the screen, 300 × 250 in the feed, and 320 × 480 for a fullscreen ad. Many Nordic sites also sell 320 × 320 and 320 × 250.
Each site and ad network sets its own limit. Many ask for a first load of around 150 KB, with more allowed once the page has loaded. Check the spec before you build.
Ads that fill the screen or most of it as the reader scrolls, such as topscroll, midscroll, double midscroll and welcome page. They are built at screen size rather than as a fixed box.
Yes. Paste the link to the page you advertise and pick the formats. MAiKE builds the banner with a layout for each size, high impact included. Custom sizes work too, and your own named formats once the MAiKE team has set them up with you.
Bring a page you advertise and your format list. We’ll show you MAiKE building them.