Business Email

Email header size

600 × 200 3:1

Max 200.0 KB ·JPG or PNG

Export at 1200 wide and set width="600" for retina.

600 × 200

Drop an image to check it Optional — the spec is above either way. Nothing is uploaded.

Cropped in your browser · your image is never uploaded

Local · never put essential text in an image

600 pixels wide is the safe email width, unchanged for two decades because it fits the narrowest common preview pane. Export at 1200 and set the width attribute to 600 so it stays sharp on high-density screens.

How to use the email header size

1 Read the dimensions above. That is the whole answer if the spec is all you came for.

2 Drop your own image in to check it against the spec — size, aspect ratio and file weight are each checked separately.

3 Turn on the safe zone to see what gets cropped or covered, then download the cropped version at the exact size.

The bigger design constraint is not the width but that many clients block images by default, and a header that carries the entire message becomes a blank rectangle. Anything essential belongs in live text, with the image as reinforcement — and every image needs alt text, because that is what the reader sees when it is blocked. Dark mode is the newer problem: several clients invert backgrounds, so a logo saved as black-on-transparent becomes invisible. A white or brand-coloured background on the logo avoids it. Keep the file under about 200 KB; several clients clip messages that get too large.

Questions

How wide should an email be? −

600 pixels. It has been the standard for two decades because it fits the narrowest preview panes.

Why does my header look blurry? +

What if images are blocked? +

Does dark mode affect email images? +

What file size should I keep it under? +

Sources

Campaign Monitor — the ultimate guide to email image blocking

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