Choosing the right Google Display Ad sizes is one of the simplest yet most strategic ways to improve visibility, engagement, and ROI across the Google Display Network. With inventory distributed across millions of websites, mobile apps, and Google-owned platforms, the size of your creative plays a major role in determining how frequently your ads appear—and how well they perform.

In 2025, performance data shows a clear trend: advertisers who prioritize standardized, widely-supported display sizes consistently gain higher viewability and stronger click-through rates. Formats like the 300×250 medium rectangle, 336×280 large rectangle, 728×90 leaderboard, 300×600 half-page ad, and 320×100 large mobile banner continue to dominate because publishers reserve their most valuable placements for these sizes.

Mobile-optimized formats are especially critical as global mobile traffic now accounts for the majority of display impressions. The 320×100 and 300×250 units stand out for mobile performance, offering clean UI integration and high CTA clarity. Meanwhile on desktop, larger cinematic sizes—such as the 970×250 billboard—deliver top-tier branding visibility for advertisers running awareness or storytelling-focused campaigns.

Beyond individual formats, the winning strategy for 2025 is variation. Uploading multiple ad sizes expands your eligible inventory, allowing Google’s system to match your creatives to more placements. Pairing fixed-size banners with Responsive Display Ads (RDAs) ensures full-funnel coverage and lets machine learning fill gaps you may not have anticipated.

Speed and file weight also matter. Google continues to enforce a 150 KB limit for image assets to maintain fast load times. Advertisers who keep files lightweight benefit from higher impressions, better user experience, and improved Quality Scores. Testing lightweight vs. heavy creative variations frequently reveals meaningful differences in CTR and CPM efficiency.

Ultimately, choosing the right display ad sizes isn’t just a design task. It’s a tactical decision that affects how widely your ads are served, how well users respond, and how quickly your campaigns scale. For a complete and updated breakdown of every high-performing Google Display Ad size for 2025, see the full guide here:

👉 https://agrowth.io/blogs/google-ads/google-display-ad-sizes