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CSS Properties

max-height

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

max-height 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-height fully.
  • Unsupported in Outlook (New), Outlook Classic.
  • Outlook Classic (Word engine, supported to at least 2029) does not fully support max-height, and its replacement changes little here; see the deprecation diff.
  • Documented before/after fixes on this page cover 21 clients, including Gmail and Gmail Android.
  • 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 Nov 29, 2021, synced by Emailens Sep 2, 2026.

Client Support

ClientCategoryEngineSupport
GmailwebmailGmail WebSupported
Gmail AndroidmobileGmail MobileSupported
Gmail iOSmobileGmail MobileSupported
Outlook 365webmailOutlook WebSupported
Outlook (New)desktopOutlook WebUnsupported
Outlook ClassicdesktopMicrosoft WordUnsupported
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

Client-by-client behaviour for max-height

Fully supports max-height (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.

No support (2): Outlook (New), Outlook Classic. Plan fallbacks for these clients before relying on max-height in production sends.

Fixes & Workarounds

Outlook (New)

Unsupported

Outlook ignores max-height. Truncate content server-side or use a fixed height.

Before (Broken)

before.html
3 lines 
<div style="max-height: 200px; overflow: hidden;">
  Long content...
</div>

After (Fixed)

fixed.html
5 lines 
<!-- Outlook ignores max-height. Truncate content server-side. -->
<div style="height: 200px;">
  Shortened content...
  <a href="https://example.com/full">Read more</a>
</div>

Outlook ignores max-height; truncate content server-side

Outlook Classic

Unsupported

Outlook ignores max-height. Truncate content server-side or use a fixed height.

Before (Broken)

before.html
3 lines 
<div style="max-height: 200px; overflow: hidden;">
  Long content...
</div>

After (Fixed)

fixed.html
5 lines 
<!-- Outlook ignores max-height. Truncate content server-side. -->
<div style="height: 200px;">
  Shortened content...
  <a href="https://example.com/full">Read more</a>
</div>

Outlook ignores max-height; truncate content server-side

Production guidance for max-height

max-height is a CSS property. Across the email client matrix, 19 of 21 tracked clients support it fully, 0 only partially, and 2 not at all. The clients most likely to require a workaround for this feature are Outlook (New), 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-height 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-height

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-height layout across 21 email clients

Preview rendering, catch CSS issues, and see how max-height 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 Nov 29, 2021 as the last time max-height was tested in a real client, 4 years before this sync. Syncing copies that result forward, it does not re-test it. Carried in @emailens/engine data v0.12.2.