Google Display Ads

Google Display Ad Sizes: Complete Specs Guide [2026]

If you’re setting up a new Google Display campaign, the first thing you’ll hit is a wall of size options. Google supports dozens of display ad dimensions across the Google Display Network (GDN), but only a handful actually drive results. The rest are either legacy formats with low inventory, mobile-only sizes that won’t reach desktop users, or oddly-shaped placements you’ll rarely see fill.

This guide covers every Google display ad size that matters in 2026 — what each one is for, where it shows up, file specs, and which sizes you should prioritize if you only have time to design a few.

Quick answer: The five Google display ad sizes you actually need are 300×250 (medium rectangle), 728×90 (leaderboard), 336×280 (large rectangle), 300×600 (half page), and 320×50 (mobile banner). These five formats cover roughly 90% of available GDN inventory. The remaining sizes (320×100, 970×250, 250×250, etc.) add incremental reach but aren’t worth designing for unless you’re scaling beyond $20K/month in display spend. For most campaigns, responsive display ads are the best default — Google auto-generates dozens of size variants from a few headlines, descriptions, and image assets, so you don’t have to design each size manually.

The Two Categories: Static Sizes vs Responsive Display Ads

Before getting into specific dimensions, understand the most important fork in the road.

Static (uploaded) display ads are images you design and upload at fixed dimensions — 300×250, 728×90, etc. Each size is a separate creative file. You control exactly what the ad looks like, but you’re committing to design, version, and refresh every size you upload.

Responsive display ads are Google’s adaptive format. You upload up to 15 images, 5 logos, 5 headlines, 5 long headlines, and 5 descriptions — and Google auto-assembles thousands of size and layout combinations from those assets. Inventory coverage is dramatically higher because Google can fit your ad into placements that no fixed-size creative would fit.

For 95% of advertisers, responsive is the right default. Static uploaded ads make sense when:

• You have brand standards that require pixel-perfect control
• You’re running highly polished creative for an enterprise brand
• You want to A/B test specific design variants against each other
• You’re working with rich-media or HTML5 ads that need motion or interactivity

If you’re running Google Display Ads at any sub-enterprise scale, start with responsive ads, then layer static creative on top once you’ve identified what works.

The Master Size Table — Every Google Display Ad Size in 2026

If you’re starting from zero and only have time to design five sizes, do these in this order: 300×250 → 728×90 → 336×280 → 300×600 → 320×50.

That five-size pack covers roughly 90% of GDN inventory and lets you launch campaigns without leaving major reach gaps.

File Specs: What Google Actually Requires

For static uploaded image ads:

For responsive display ads, Google’s asset specs are more permissive but still have hard limits:

Common gotcha: Google auto-applies AI image enhancements to responsive display ads by default — auto-cropping, aspect ratio changes, and even AI-generated variants. If you have brand standards, turn off “asset enhancements” in your campaign settings, or the ads that ship may not match what you uploaded.

The Size That Actually Performs: 300×250

Across nearly every category and industry, the 300×250 medium rectangle delivers the highest combined reach and CTR on the GDN. Every published GDN benchmark we’ve seen over the past five years lists 300×250 as either the #1 or #2 best-performing size by CTR — typically tied with 336×280.

Why does 300×250 win?

1. Inventory volume. It’s the most common publisher placement on the web. Almost every site that runs display ads supports 300×250 in their sidebar, in-article slot, or footer.
2. Mobile + desktop reach. It scales gracefully across both contexts. Most other sizes are biased toward one device.
3. Reading position. 300×250 placements tend to sit inside or next to article content, where users are paying attention. Compare to 728×90 leaderboards, which sit above content where users haven’t engaged yet.
4. Format flexibility. Square-ish dimensions accommodate hero image + headline + CTA layouts cleanly. Long horizontal sizes (728×90) are constrained by their aspect ratio.

If you’re producing creative for a campaign and have to pick one size to obsess over, make it 300×250. Get it right before you build anything else.

Mobile vs Desktop: How to Think About It

Mobile is where most GDN impressions come from in 2026 — typically 65–75% of total impressions for non-B2B advertisers. For B2B, that flips: desktop usually accounts for 55–70% of impressions because B2B buyers research from work computers.

The implication: size strategy should match where your audience actually clicks.

For consumer / DTC / B2C advertisers, your priority order should be:

1. 300×250 (works on both)
2. 320×50 (mobile banner)
3. 336×280 (mobile in-article)
4. 320×100 (larger mobile)
5. 728×90 (desktop fill)

For B2B / SaaS / enterprise advertisers:

1. 300×250
2. 728×90
3. 300×600 (high desktop impact)
4. 970×250 (billboard, when budget allows premium)
5. 320×50 (mobile, lower priority)

What Doesn’t Work: Common Display Ad Sizing Mistakes

The fastest way to underperform on the GDN is to upload static creative that violates one of these rules. Each of these is something we’ve seen kill performance on real campaigns.

1. Skipping 320×50 because “we don’t run mobile”

You think you’re running desktop-only. Google fills inventory wherever it’s cheapest, and a meaningful share of GDN inventory is mobile by default. If you don’t upload a 320×50 (or use responsive display ads), Google either won’t serve mobile placements at all (lost reach) or will scale your 300×250 down awkwardly into mobile slots. Either way, performance suffers.

2. Text-heavy creative

The classic GDN mistake. A 300×250 creative with three lines of body copy and a long CTA button reads fine on a 27-inch monitor and is illegible on a phone. Display ads are not landing pages. The headline should be 4–8 words. The CTA should be 1–3 words. The visual should do the heavy lifting.

3. Low-resolution images

Google penalizes blurry creative — both in CTR (users don’t click pixelated ads) and in delivery (Google’s quality scoring deprioritizes low-res). Upload at 2x the displayed dimensions to ensure crisp rendering on Retina displays. So a 300×250 ad should be designed at 600×500 and exported.

4. Missing safe zones near edges

Some publisher placements crop the outer 10–15 pixels of your ad. If your CTA button is jammed against the right edge, it gets clipped on certain placements. Keep critical content (logo, CTA, key copy) at least 15 pixels in from each edge.

5. White ads with no visible border

Google explicitly requires a visible border on light-background ads. If you skip this, your ads may not get approved, or they’ll get served in placements where they blend invisibly into the page background. Add a 1–2px border in a contrast color (gray works fine).

6. Forgetting the responsive display ad option

Designing 8 static sizes when you could upload 5 headlines + 5 images and let Google’s responsive engine do the work. For most accounts, responsive ads outperform static ads on raw conversion volume because they reach inventory static sizes can’t fit. Run responsive as your primary creative format, then add static sizes only if you’re seeing specific volume gaps.

Static Sizes vs Responsive: Side-by-Side Comparison

Most well-run accounts use both — responsive display ads as the volume driver, with 2–3 static sizes (typically 300×250, 728×90, 300×600) layered on top for premium placements where pixel-perfect creative matters.

How to Decide Which Sizes to Design

A practical decision framework, in order:

1. If your monthly display spend is under $5K, run responsive display ads only. Don’t waste time designing static sizes — you don’t have the volume to A/B test them properly.
2. If your monthly display spend is $5K–$25K, run responsive ads + the 5-size pack (300×250, 728×90, 336×280, 300×600, 320×50). That covers ~90% of GDN inventory.
3. If you’re at $25K+ per month, expand to the full 8-size pack (add 970×250, 320×100, and 250×250). At this spend level, the incremental reach is worth the design overhead.
4. If you’re running enterprise brand campaigns ($100K+ per month), design every size including legacy formats (160×600, 970×90). Premium publishers often have inventory only in older formats, and you’ll want to fill it with branded creative rather than letting Google scale.

What This Means for Your Campaign Setup

If you’re starting a new Google Display campaign:

• Upload responsive display ads with at least 10 images, 5 headlines, and 5 descriptions
• Design and upload static 300×250 creative for high-CTR placements
• Add 728×90 and 320×50 to cover desktop and mobile reach gaps
• Skip the legacy sizes (468×60, 234×60, 120×600) entirely
• Turn off “asset enhancements” if you have brand standards
• Plan to refresh creative every 4–6 weeks (display ad fatigue is real and measurable)

The size mix doesn’t make or break a campaign — strategy and targeting do. But shipping the wrong size mix is one of those quiet inefficiencies that costs you reach without showing up in any obvious metric. A 90% inventory coverage from the right 5 sizes will outperform a confused 12-size mix with quality issues every time.

If you want to skip the trial-and-error, our Google display ads service builds full creative size packs as part of every engagement — and our buyer’s guide to picking a display agency covers what to look for if you’re evaluating partners. Get in touch if you want a free audit of your current creative size coverage.