max-width

Client-by-client behaviour for max-width

Fully supports max-width (19): Gmail, Gmail Android, Gmail iOS, Outlook 365, Outlook iOS, Outlook Android, Outlook for Mac, Apple Mail, Apple Mail iOS, Yahoo Mail, Yahoo Mail Android, Yahoo Mail iOS, Samsung Mail, Thunderbird, HEY Mail, Proton Mail, AOL Mail, Fastmail, Superhuman.

Partial support (2): Outlook (New), Outlook Classic. Expect rendering quirks unique to each engine. Partial support typically means a subset of values, an ignored shorthand, or sanitizer-specific rewrites.

Fixes & Workarounds

<div style="max-width: 600px; margin: 0 auto;">
  Content here
</div>

<!--[if mso]>
<table role="presentation" width="600" cellpadding="0"
  cellspacing="0" border="0" align="center"><tr><td>
<![endif]-->
<div style="max-width: 600px; margin: 0 auto;">
  Content here
</div>
<!--[if mso]>
</td></tr></table>
<![endif]-->

Production guidance for max-width

max-width is a CSS property. Across the email client matrix, 19 of 15 tracked clients support it fully, 2 only partially, and 0 not at all. The clients most likely to require a workaround for this feature are Outlook Classic. Each of them needs a tailored fallback. See the per-client examples above for the specific code fix Emailens recommends.

When in doubt, ship a baseline that renders without max-width and treat it as progressive enhancement on clients where support is verified. Emailens automatically detects cross-client divergence on this feature when you preview an email, so you can see exactly which template paths break before a campaign goes out.