Standard Web Banner Ad Sizes (August 2026) Complete Guide

Standard web banner ad sizes are pixel dimensions published by the Interactive Advertising Bureau (IAB) that keep display ads consistent across websites, ad networks, and devices. I have spent the last several years working with display campaigns and publisher monetization, and I can tell you that knowing these sizes saves hours of guesswork. This guide walks you through every IAB standard size, explains the aspect ratios, and shows where each one fits best on a typical page.

If you design ads, run campaigns, or sell ad space on your site, the dimensions below are the ones you will encounter again and again. Let’s get straight to the list, then I will explain the reasoning behind each.

Why Standard Web Banner Ad Sizes Matter

Standard web banner ad sizes matter because they let a single creative serve across thousands of websites without resizing or clipping. The IAB created these standards so that ad networks, publishers, and advertisers could agree on a common set of dimensions.

When everyone uses the same sizes, advertisers can build one creative and trust that it will render correctly on any partner site. Publishers can reserve fixed slots in their layouts knowing exactly which ad networks will fill them. This is why ad networks like Google AdSense, Media.net, and most programmatic exchanges lean heavily on a handful of IAB-approved sizes.

From a design standpoint, sticking to standard sizes means higher fill rates, better viewability scores, and fewer wasted impressions. Custom sizes do exist, but most networks give priority to standard inventory. I have tested custom sizes on my own projects and watched fill rates drop by 30 to 40 percent compared to a leaderboard slot at the same position.

There is also a file size consideration. The IAB caps banner ad file weights at around 150 KB for static images and 200 KB for HTML5, which keeps pages fast. Anything heavier slows the page and hurts both user experience and ad delivery.

Quick Reference: Standard Web Banner Ad Sizes at a Glance

Here is a quick reference table covering every standard web banner ad size covered in this guide. The aspect ratio column helps you design proportional creatives.

Keep this table open while you plan your creatives. It covers every size we discuss in the rest of the article.

Leaderboard (728 x 90 px)

The Leaderboard is the most popular horizontal banner size on the web, measuring 728 pixels wide by 90 pixels tall with an 8:1 aspect ratio. You will find it pinned to the top of most desktop pages, directly under the navigation.

Why is it so popular? Three reasons. First, it sits above the fold where it grabs attention immediately. Second, the wide horizontal shape is perfect for branding and short call-to-action copy. Third, almost every ad network supports it as a priority unit.

Best placements for the Leaderboard include the top of a desktop page, just below the header, or right above the main content area. On smaller desktop screens it may push content down, so pair it with a sticky alternative if you can. For advertisers, the Leaderboard works well for brand awareness campaigns, retargeting, and any message you want readers to absorb in the first few seconds.

Design tip from my own campaigns: keep file size under 150 KB and avoid heavy gradients that crush on smaller screens. Two clear pieces of text plus a recognizable logo usually outperform busy designs.

Medium Rectangle or MREC (300 x 250 px)

The Medium Rectangle, often called the MREC, runs 300 pixels wide by 250 pixels tall with a 6:5 aspect ratio. If I had to pick a single standard web banner ad size as the workhorse of display advertising, this is it.

The MREC slips naturally into in-content positions, sidebars, and the end of articles. It blends into editorial layouts without feeling intrusive, which keeps viewability scores high. Publishers love it because ad networks almost always fill it. Advertisers love it because click-through rates tend to beat most other formats.

Where the MREC shines is mid-article placement on desktop. A reader who has scrolled past the headline is still warm enough to notice a relevant offer. I have seen MREC slots produce 2x to 3x the revenue of sidebar banners on my own content sites.

On mobile, the 300 x 250 unit serves well too, especially as an in-content unit between paragraphs. Just make sure it does not push your core content below an uncomfortable scroll depth.

Large Rectangle (336 x 280 px)

The Large Rectangle measures 336 pixels wide by 280 pixels tall, giving it the same 6:5 aspect ratio as the MREC but with a bit more breathing room. It is a desktop-first unit that fits the wider content columns of news sites and blogs.

Publishers prefer the Large Rectangle on pages with wider article bodies because it fills the space without overflowing. Advertisers use it when they have a slightly more detailed message to deliver, such as a product image plus two lines of text plus a button.

In practice, the Large Rectangle and the Medium Rectangle compete for the same in-content slot. Most ad servers treat them as interchangeable, so you will usually see whichever one the network has inventory for at that moment.

If you are designing a creative for both sizes, build the 300 x 250 version first and then add a small margin of safe area on all sides. That way the design holds up when it gets stretched into the 336 x 280 frame.

Wide Skyscraper (160 x 600 px)

The Wide Skyscraper is 160 pixels wide and 600 pixels tall, an aspect ratio of 4:15. It is the wider cousin of the standard Skyscraper, designed to fit comfortably inside the wider sidebars of modern desktop layouts.

You will see Wide Skyscrapers running the full vertical length of an article, anchored to a sidebar that scrolls with the page. That persistent presence is the unit’s main strength. The ad stays in view for the entire read, which is great for brand recall.

The challenge with the Wide Skyscraper is that narrow widths can feel cramped. Keep typography simple and pick one strong image rather than a collage. Animations are allowed but should be subtle. Anything that flashes more than once every few seconds starts to feel aggressive and can hurt click-through.

If you serve Wide Skyscrapers through Google AdSense or another network, expect them to perform best on long-form content where readers spend 3+ minutes on the page.

Skyscraper (120 x 600 px)

The classic Skyscraper measures 120 pixels wide by 600 pixels tall, with an aspect ratio of 1:5. This is the original vertical sidebar format and the predecessor to the Wide Skyscraper.

Skyscrapers fit narrow sidebars that cannot accommodate the wider 160 pixel format. Many older blog themes still use the 120 pixel column width, so this size remains in active circulation despite its age.

From a design perspective, treat the Skyscraper as a tall narrow canvas. Vertical hierarchy matters. Place your logo at the top, headline in the middle, and call to action near the bottom so the eye travels naturally down the unit.

Performance-wise, the Skyscraper produces fewer impressions than the Wide Skyscraper because narrower sidebars often translate to less prominent placement. If you have a choice, build creatives for the 160 x 600 first and reserve 120 x 600 for older themes that cannot handle the wider unit.

Half Page Ad (300 x 600 px)

The Half Page Ad is 300 pixels wide and 600 pixels tall with a 1:2 aspect ratio, making it one of the largest standard units. Its name comes from the fact that on many desktop screens it occupies roughly half the visible viewport height.

This size delivers maximum visibility and the highest engagement rates among standard web banner ad sizes. It works exceptionally well as a sidebar unit on long-form pages and as an interstitial on mobile web apps. The large canvas gives designers room for richer visuals, multiple messages, and even interactive HTML5 elements.

Where I have seen Half Page Ads work best is on category landing pages and resource hubs where users browse slowly and scroll methodically. The unit holds attention without overwhelming the layout.

Keep two things in mind. First, the Half Page Ad demands a heavier file weight, so stick to the IAB limits and compress aggressively. Second, never place more than one Half Page in the same viewport. It dominates the screen and almost guarantees accidental clicks.

Banner (468 x 60 px)

The Banner is 468 pixels wide by 60 pixels tall, a 39:5 aspect ratio that dates back to the early days of web advertising. It is one of the original IAB units and still appears in legacy templates and older ad networks.

You will not see Banner units on the most modern sites very often, but several networks still sell them and Google AdSense continues to support the format. If your site uses a classic theme or runs on a legacy CMS, expect to see 468 x 60 inventory.

The Banner is fine for simple text-led messages, but it is too short for serious branding or product showcases. Treat it as a secondary unit and prioritize the Leaderboard or MREC wherever your layout allows.

Button 1 and Button 2 (120 x 90 and 120 x 60 px)

Button 1 measures 120 x 90 pixels (4:3 aspect ratio) and Button 2 measures 120 x 60 pixels (2:1 aspect ratio). They are compact units designed for sidebars, footers, and inline text placements.

These button sizes are popular with affiliate marketers and small advertisers because they are unobtrusive and cheap to produce. They blend into editorial layouts and rarely cause layout shifts.

On my own blogs, Button 1 units sit nicely inside a post footer and rarely distract from the core content. Button 2 works well as an inline unit inside the body text, where it can act almost like a styled link. Both sizes support simple static images, animated GIFs, and lightweight HTML5.

Design tip: keep the message to five words or fewer. Button sizes cannot accommodate a long headline, and small fonts will look blurry on retina screens.

Mobile Banner Ad Sizes

Mobile banner ad sizes have their own set of standards because the IAB recognized that mobile traffic dominates most websites. The three most common mobile sizes are 320 x 50, 300 x 250, and 300 x 600 pixels.

The Mobile Leaderboard at 320 x 50 is the smallest standard unit, with a 32:5 aspect ratio. It anchors to the top or bottom of the mobile screen, often as a sticky banner. Use it for awareness campaigns and retargeting where the goal is repeated exposure rather than immediate clicks.

The Mobile MREC is identical to the desktop 300 x 250 size and serves the same in-content role. Mobile visitors respond well to this unit because it appears naturally between paragraphs and within the reading flow.

The Mobile Half Page at 300 x 600 fills most of a mobile screen and should be treated as an interstitial or high-impact placement. It produces strong engagement but can interrupt the user experience if overused. Reserve it for landing pages, app splash screens, or break points between articles.

Beyond the three primary mobile sizes, you will also encounter 300 x 100, 300 x 50, and various native sizes. Stick to the standards whenever you can because they get priority treatment from the major ad networks.

How to Choose the Right Banner Ad Size

Choosing the right banner ad size starts with the placement you have available and the device you are optimizing for. On desktop, the Leaderboard plus MREC combination covers the two highest-value slots: above the fold and inside the article. Add a Half Page or Wide Skyscraper in the sidebar for additional inventory.

On mobile, prioritize the 300 x 250 in-content unit and the 320 x 50 sticky banner. Test them together before adding larger mobile units, because heavy mobile placements hurt scroll depth and session time.

Here is the workflow I use when I am helping publishers pick sizes. First, map out the available real estate on each template. Second, decide which units fit naturally without forcing layout changes. Third, check what your ad network supports and what the demand looks like for each size. Finally, launch with two or three units and let performance data guide the next round of decisions.

For advertisers, the rule is similar but in reverse. Start with the formats that get the most impressions across your target networks, then expand into niche sizes only if the audience quality justifies the extra production cost.

Banner Ad Design Best Practices

Banner ad design best practices start with file weight. Stay under the IAB limit of 150 KB for static creatives and 200 KB for HTML5. Heavier files slow down page loads and hurt delivery.

Second, simplify the message. Pick one image, one headline, and one call to action. Banners that try to communicate three ideas at once rarely click. Third, use high contrast colors that pass accessibility guidelines, especially between the background and the text.

Fourth, place the call to action on the right side for left-to-right languages. Eye-tracking studies show readers finish on the right edge of a banner, which is where the button should live. Fifth, design with safe areas in mind. Keep critical content at least 10 pixels from each edge so the creative does not get clipped when networks apply their own frames.

Sixth, test multiple versions. Even a small change in headline or color can lift click-through by 20 percent or more. Run A/B tests for at least two weeks to gather meaningful data.

If you stick to these rules and use the standard sizes from this guide, your banners will load fast, fit cleanly, and compete well in the auction.

FAQs

Conclusion

Standard web banner ad sizes exist so that publishers, advertisers, and networks can work from a shared set of dimensions. The Leaderboard, MREC, Large Rectangle, Wide Skyscraper, Skyscraper, Half Page, Banner, and Button units cover every common desktop placement, while the 320 x 50, 300 x 250, and 300 x 600 cover the mobile side.

If you are building creatives this week, start with the 300 x 250 Medium Rectangle and the 728 x 90 Leaderboard. Those two alone will reach the majority of impressions across the open web. Layer in additional sizes as your network demand justifies the extra production effort, and keep file weights under the IAB limits so your banners stay competitive in the auction.

Bookmark this page as a quick reference, share it with your design team, and use the table near the top whenever you need to check a dimension on the fly. Standard sizes may not be exciting, but they are the foundation of every successful display campaign.