CSS property · 10 real installs 14 Oct 2026 · data last changed 10 Nov 2026

overflow in email clients

Works in 4 of 21. Not supported in Outlook Classic. Partial in Gmail, Gmail Android, Gmail iOS and 13 more.

Your reader in Outlook Classic sees the email without overflow, even if it looks right where you tested it.

caniemail (MIT) via @emailens/engine 0.18.22

What to do instead in Outlook Classic

Content will always be visible; design for full content display

instead

5 lines

<!-- Show full content, or truncate server-side -->
<div style="max-height: 200px;">
  Shortened content that fits...
  <a href="https://example.com/full">Read more</a>
</div>

Show the original

before

3 lines

<div style="max-height: 200px; overflow: hidden;">
  Long content that gets clipped...
</div>

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overflow on 10 real installs

One Emailens probe, screenshotted on each install on 14 October 2026, next to our live preview of the same client. Where overflow is supported you should see: only one line shows.

The Emailens probe for overflow on a real Outlook 2019 (Windows) — Outlook Classic

The Emailens probe for overflow on a real Outlook 2016 (Windows) — Outlook Classic

The Emailens probe for overflow on a real Outlook.com — Outlook 365

The same probe in the Emailens live preview of Outlook 365 — Outlook 365

The Emailens probe for overflow on a real Apple Mail (macOS) — Apple Mail

The same probe in the Emailens live preview of Apple Mail — Apple Mail

The Emailens probe for overflow on a real Apple Mail (iPhone 13) — Apple Mail iOS

The same probe in the Emailens live preview of Apple Mail iOS — Apple Mail iOS

The Emailens probe for overflow on a real Yahoo Mail — Yahoo Mail

The same probe in the Emailens live preview of Yahoo Mail — Yahoo Mail

Also captured, not counted as evidence (3)

Outlook for Microsoft 365 · not mapped to an engine client yet Real screenshot
Outlook 2019 for Mac (legacy app) · not counted as Outlook for Mac Real screenshot
This is the legacy Outlook for Mac app. The new Outlook for Mac, which the table describes, drops gradients, grid sizing functions, var() and more.
Gmail (web) · not counted as Gmail Real screenshot
This Gmail install does not apply Gmail's sanitiser, so it shows more than real Gmail does.

Every account includes one free real-device check in classic Outlook, Outlook for Mac and Apple Mail, after you verify your email and run one preview, while this month's free capacity lasts. How real-device checks work →

All 21 clients, problems first

Client	Support
Outlook Classic	Not supported
Gmail	Partial ^{See caveat 1}
Gmail Android	Partial ^{See caveat 2}
Gmail iOS	Partial ^{See caveat 1}
Outlook 365	Partial ^{See caveat 1}
Outlook (New)	Partial ^{See caveat 1}
Outlook iOS	Partial ^{See caveat 1}
Outlook Android	Partial ^{See caveat 2}
Outlook for Mac	Partial ^{See caveat 1}
Apple Mail	Partial ^{See caveat 1}
Apple Mail iOS	Partial ^{See caveat 1}
Yahoo Mail	Partial ^{See caveat 1}
Yahoo Mail Android	Partial ^{See caveat 2}
Yahoo Mail iOS	Partial ^{See caveat 1}
Samsung Mail	Partial ^{See caveat 1}
Proton Mail	Partial ^{See caveat 3}
AOL Mail	Partial ^{See caveat 4}

Works in 4: Thunderbird, HEY Mail, Fastmail and 1 more. Show all

Client	Support
Thunderbird	Works
HEY Mail	Works
Fastmail	Works
Superhuman	Works

Caveats (4)

1. Gmail, Gmail iOS, Outlook 365, Outlook (New), Outlook iOS, Outlook for Mac, Apple Mail, Apple Mail iOS, Yahoo Mail, Yahoo Mail iOS, Samsung Mail: Partial. overflow-block & overflow-inline not supported.
2. Gmail Android, Outlook Android, Yahoo Mail Android: Buggy. Cannot scroll through to hidden content. Partial. overflow-block & overflow-inline not supported.
3. Proton Mail: Partial. Support for overflow-block & overflow-inline depends on browser support. Buggy. Cannot scroll through to hidden content.
4. AOL Mail: Partial. overflow-block & overflow-inline not supported. Buggy. Cannot scroll through to hidden content.

Caveats as recorded by caniemail (MIT), one entry per wording.

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overflow in Outlook Classic · Every feature in Outlook Classic · All email CSS features · What real installs show

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