How many email clients support max-height?

It works in 20 of 21, not supported in Outlook Classic.

Does max-height work in Fastmail?

max-height works in Fastmail. Closest to HEY Mail: Fastmail, which agrees on 173 of the 235 features both are tested on.

max-height in HEY Mail

Works max-height works in HEY Mail.

Works in 20 of 21 · not supported in 1

Which clients

Works: Gmail, Gmail Android, Gmail iOS, Outlook 365, Outlook (New), 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
Not supported: Outlook Classic

The fix for the clients that need it

Needed in 1 of 21: Outlook Classic.

Outlook ignores max-height; truncate content server-side

instead

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>

Show the original

before

3 lines

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

A free account opens all 21 clients and keeps your checks for 7 days. Create a free account →

Your next question

Every feature in HEY Mail · max-height in every client

Questions

How many email clients support max-height?: It works in 20 of 21, not supported in Outlook Classic.
Does max-height work in Fastmail?: max-height works in Fastmail. Closest to HEY Mail: Fastmail, which agrees on 173 of the 235 features both are tested on.

To see what in your email HEY Mail does not support, paste the whole email.

Check your email, free

No signup · Five clients free, Outlook Classic included · All 21 with an account

The checker needs a computer screen.

caniemail (MIT) via @emailens/engine 0.18.22 · tested upstream 29 Nov 2021 · data last changed 10 Nov 2026 · Outlook (New) cells are the engine's mapping