Skip to main content
Emailens
Sign inTry Free
CSS Properties

max-width

CSS property · 19 supported, 2 partial, 0 unsupported across 21 clients

max-width is safe in 19 of 21 email clients as of Sep 2, 2026, the holdouts are Outlook (New), Outlook Classic.

  • 7/7 webmail, 4/6 desktop, 8/8 mobile clients support max-width fully.
  • Partial in Outlook (New), Outlook Classic, behavior differs from browsers, test before relying on it.
  • Outlook Classic (Word engine, supported to at least 2029) does not fully support max-width, and its replacement changes little here; see the deprecation diff.
  • Documented before/after fixes on this page cover 1 client, including Outlook Classic.
  • Across all clients, only 6 of 298 tracked HTML/CSS features render identically everywhere.

Source: caniemail.com (MIT), via the Emailens engine. Last tested upstream Aug 2, 2019, synced by Emailens Sep 2, 2026.

Client Support

ClientCategoryEngineSupport
GmailwebmailGmail WebSupported
Gmail AndroidmobileGmail MobileSupported
Gmail iOSmobileGmail MobileSupported
Outlook 365webmailOutlook WebSupported
Outlook (New)desktopOutlook WebPartialSee caveat 1
Outlook ClassicdesktopMicrosoft WordPartialSee caveat 1
Outlook iOSmobileOutlook MobileSupported
Outlook AndroidmobileOutlook MobileSupported
Outlook for MacdesktopWebKitSupported
Apple MaildesktopWebKitSupported
Apple Mail iOSmobileWebKitSupported
Yahoo MailwebmailYahooSupported
Yahoo Mail AndroidmobileYahooSupported
Yahoo Mail iOSmobileYahooSupported
Samsung MailmobileSamsungSupported
ThunderbirddesktopGeckoSupported
HEY MailwebmailWebKitSupported
Proton MailwebmailProtonSupported
AOL MailwebmailAOLSupported
FastmailwebmailFastmailSupported
SuperhumandesktopBlinkSupported

Documented caveats (1)

  1. 1.Outlook (New), Outlook Classic: Partial. Only works on <table> elements.

Caveats recorded by caniemail.com (MIT) and carried verbatim, one entry per wording rather than per client.

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

Outlook (New)

Partial

Use a fixed-width table wrapper for maximum compatibility.

Outlook Classic

Partial

Use a fixed width on table cells instead of max-width.

Before (Broken)

before.html
3 lines 
<div style="max-width: 600px; margin: 0 auto;">
  Content here
</div>

After (Fixed)

fixed.html
10 lines 
<!--[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]-->

Use a fixed-width table wrapper for Outlook

Production guidance for max-width

max-width is a CSS property. Across the email client matrix, 19 of 21 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.

Related Features

!important accent-color align-items animation aspect-ratio backdrop-filter background background-blend-mode

Check your own HTML for max-width

Paste your own, or run the sample below. Analyzed in this page, with no signup and nothing stored.
Zero-Friction Engine Preview

Test your max-width layout across 21 email clients

Preview rendering, catch CSS issues, and see how max-width displays across Outlook, Gmail, and Apple Mail. Free, no account needed.

Instant live preview · No signup required · 21 email engines

Last tested upstream: · Last synced by Emailens:

caniemail.com (MIT) records Aug 2, 2019 as the last time max-width was tested in a real client, 7 years before this sync. Syncing copies that result forward, it does not re-test it. Carried in @emailens/engine data v0.12.2.