Mobile traffic now accounts for over 60% of all web visits. If your banners aren’t optimized for small screens, you are literally throwing away half your budget.
Designing for mobile isn’t just about shrinking your desktop ads—it’s about clarity, touch targets, and fast loading times. Below, we outline the essential rules and provide free tools to validate your sizes.
📱 Mobile Ad Validator
Are your mobile ads the right size? Check your files instantly.
The “Fat Finger” Rule: Button Size Matters
On a desktop, a mouse pointer is precise. On mobile, a thumb is clumsy. This is often called the “Fat Finger” problem.
The Fix: Ensure your Call to Action (CTA) button is at least 44×44 pixels. Anything smaller frustrates users and leads to accidental clicks (which Google penalizes).
Top Mobile Sizes You Must Use
While desktop allows for large leaderboards, mobile real estate is expensive. Stick to these standard IAB mobile units:
1. The Mobile Leaderboard (320×50)
The standard “Anchor Ad” that sticks to the bottom of the screen. Small, inexpensive, and ubiquitous.
2. The Large Mobile Banner (320×100)
Twice the height of the standard leaderboard, offering room for two lines of text or a logo.
3. The Mobile Interstitial (320×480)
Covers the entire screen between game levels or articles. Commands high attention.
Tips for High-Converting Mobile Design
1. Keep Text Minimal
You have milliseconds to grab attention. Do not write a paragraph. Use 3-5 words max (e.g., “50% Off. Shop Now.”).
2. High Contrast is Key
Mobile screens are often viewed in sunlight. Use bold, high-contrast colors like black on yellow or white on blue.
3. Optimize File Size
Keep your banners under 50KB. Heavy HTML5 animations lag on phones.
Need lighter files? Tools like Envato Elements can help you compress assets without quality loss.
Summary
Mobile optimization is survival. Stick to standard sizes and keep designs bold.
Ready to launch? Use our Master List to check every size: