Email Banner Size Guide

Getting email banner dimensions right is one of those things that seems simple until you realize your beautiful design looks broken in Outlook, gets cropped on mobile, or appears blurry on an iPhone. Every email client renders images slightly differently, and there's no single "perfect" size — but there are some very safe choices that work almost everywhere.

The short answer: 600 × 200px is the safest, most universally compatible email banner size. It works in every major email client, doesn't take up too much vertical space, and gives you enough room for your branding and message. For retina screens, design at 1200 × 400px and display at 600 × 200px.

This guide covers every standard banner size, when to use each one, email client compatibility data, and a custom checker so you can validate your own dimensions. If you're building email campaigns, pair this with our email word counter to make sure your total email stays under clipping thresholds, and use our dark mode preview to see how your banner looks across devices.

For the rest of your email design, check our dark mode preview tool (because banners can look very different inverted) and our contrast checker to make sure text overlays on banners remain readable.