Standard banner ad sizes that perform in 2026

The six banner ad sizes worth building in 2026 are the IAB standards: 300x250, 728x90, 160x600, 300x600, 320x50 and 970x250. The 300x250 Medium Rectangle still wins the most inventory, so it anchors every set. Build all six from one master, and you cover desktop, mobile and premium placements without redrawing each unit.

These dimensions have not changed much because buyers and publishers agreed on them years ago. Sticking to the standards means your creative fits clean slots on almost every exchange, instead of getting rejected or cropped. The rest of this guide covers which sizes earn placements, what viewability requires, and how to ship the full set efficiently.

Which banner ad sizes should you build first?

If you build nothing else, build the three highest-inventory units: 300x250, 728x90 and 160x600. Together they reach a large share of placements across European supply, which means your campaign keeps serving even when premium slots are scarce. The Medium Rectangle alone fits inline content blocks on news sites, blogs and feeds.

After those three, add 320x50 to capture mobile reach and 970x250 for above-the-fold brand buys on desktop. The 300x600 Half Page rounds out the set with strong vertical impact. Here are all six standards and where each one earns its place.

Why does 300x250 win the most inventory?

The Medium Rectangle wins because publishers place it inside the article body, where readers are already looking. That inline position keeps the unit on screen while someone reads, which raises the odds it counts as viewable. A sidebar skyscraper can sit below the fold and never get seen, but a 300x250 wrapped in paragraph text travels down the page with the reader.

It also works on both desktop and mobile layouts without a separate design, so a single 300x250 fills more slots than any other size. For agencies running programmatic at scale, that flexibility is the reason the unit appears in nearly every media plan. If you want the mechanics of how these slots get bought, our explainer on what programmatic advertising actually involves walks through the auction.

What CTR should you expect from display banners?

Click-through rates on display are low by design, and that is normal. Across the Google Display Network the average CTR sits around 0.46%. Broader programmatic display runs closer to 0.27%, and cold or remnant inventory lands in the 0.05% to 0.1% range. None of these numbers signal a broken creative; display earns most of its value through view-based recall rather than clicks.

So judging a banner purely on clicks misreads what the format does. A 970x250 Billboard above the fold builds brand memory whether or not anyone clicks. The figures below give you a sanity check: if your programmatic CTR is near 0.27%, you are roughly in line with the market, and you should look at viewability and frequency before assuming the creative is the problem.

How does viewability change banner performance?

Viewability decides whether an impression had any chance to work, so it matters more than size. The MRC viewability standard requires 50% of an ad’s pixels to be in view for at least 1 continuous second. Large formats over 242,500 pixels, like the 970x250 Billboard, use a looser bar: 30% of pixels for 1 second, since the full unit rarely fits on one screen at once.

The payoff is direct. Google research found that viewable ads convert roughly 4x better than non-viewable ones, which is why placement quality drives results more than dimensions. Industry desktop display viewability reached about 72.2% in 2024 per IAS, meaning more than a quarter of desktop impressions still never met the standard. Tightening that gap is usually the fastest performance win available, and our notes on how to improve ad viewability cover the levers that move it.

Should you use responsive or fixed-size display ads?

Use both, because they solve different problems. Responsive display ads auto-fit many slots from one set of assets: you supply images, a logo, headlines and descriptions, and the exchange recombines them to match whatever placement is available. That coverage reaches small and odd-shaped slots you would never design by hand, which keeps delivery high on long-tail supply.

Fixed-size HTML5 units give you exact control where it counts. On premium buys, a hand-built 300x600 looks far better than an auto-assembled one, and brand buyers often require named standard sizes. The practical answer is to run responsive for reach and fixed sizes for the placements you care about most. One HTML5 master can export all six fixed sizes, so you get pixel control without redrawing each unit from scratch.

How do you ship all six sizes from one master?

Build one HTML5 creative master, then export every fixed size from it. The structure stays the same across units: a background, a logo, a headline, and a call to action that you reposition for each aspect ratio. Animation timing, colour and copy carry over, so a change to the message updates everywhere instead of in six separate files. This is the core of our creative production workflow.

Keep the initial load light. Aim for around 150KB so the banner renders before the page scrolls past it, since a heavy file that loads after the slot leaves view never counts as viewable. Strip unused fonts, compress images, and avoid loading every animation frame up front. Light, fast creative protects the viewability numbers that decide whether the impression converts at all.

How should you prioritise a banner set on a tight budget?

Start with the three highest-inventory units and expand outward. The 300x250, 728x90 and 160x600 reach the widest pool of placements, so they deliver the most served impressions per euro of production. If you can only fund three sizes this quarter, fund those, and add the rest as the campaign proves out.

Next, weigh your audience split. A mobile-heavy media plan needs 320x50 before it needs 970x250, while a brand-awareness push on desktop publishers benefits from the Billboard and the 300x600 Half Page. The point is to match the set to where your inventory actually sits, not to chase every standard at once. Because all six come from one master, you can stage the rollout cheaply: ship the core three, then export the remaining sizes when the budget clears.

The short version

The six IAB standard sizes are the set worth building, and the 300x250 Medium Rectangle earns its place at the top because it wins the most inventory and stays in view inside content. Prioritise the three highest-inventory units, treat viewability as the metric that decides outcomes, and produce every size from one HTML5 master to keep the cost per unit low. Do that, and your banners fit clean slots, load fast, and serve where buyers can actually see them.