CSS Properties

font-stretch

CSS property · 9 supported, 0 partial, 8 unsupported across 21 clients

9 of 21 email clients render font-stretch fully (Sep 2, 2026 data); it breaks outright in Gmail Android, Outlook (New), Outlook Android and 5 more.

3/7 webmail, 3/6 desktop, 3/8 mobile clients support font-stretch fully.
Unsupported in Gmail Android, Outlook (New), Outlook Android, Yahoo Mail and 4 more.
Outlook Classic (Word engine, supported to at least 2029) does not fully support font-stretch, and its replacement changes little here; see the deprecation diff.
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 Sep 23, 2023, synced by Emailens Sep 2, 2026.

Client Support

Client	Category	Engine	Support
Gmail	webmail	Gmail Web	Supported^{See caveat 1}
Gmail Android	mobile	Gmail Mobile	Unsupported
Gmail iOS	mobile	Gmail Mobile	Supported
Outlook 365	webmail	Outlook Web	Supported^{See caveat 1}
Outlook (New)	desktop	Outlook Web	Unsupported
Outlook Classic	desktop	Microsoft Word	Unknown
Outlook iOS	mobile	Outlook Mobile	Supported
Outlook Android	mobile	Outlook Mobile	Unsupported
Outlook for Mac	desktop	WebKit	Supported
Apple Mail	desktop	WebKit	Supported
Apple Mail iOS	mobile	WebKit	Supported
Yahoo Mail	webmail	Yahoo	Unsupported
Yahoo Mail Android	mobile	Yahoo	Unsupported
Yahoo Mail iOS	mobile	Yahoo	Unsupported
Samsung Mail	mobile	Samsung	Unsupported
Thunderbird	desktop	Gecko	Supported
HEY Mail	webmail	WebKit	Unknown
Proton Mail	webmail	Proton	Supported^{See caveat 1}
AOL Mail	webmail	AOL	Unsupported
Fastmail	webmail	Fastmail	Unknown
Superhuman	desktop	Blink	Unknown

Documented caveats (1)

1.Gmail, Outlook 365, Proton Mail: Partial. Depends on the browser. There is currently a bug in Chrome/Edge where font-stretch does not work for variable fonts.

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

Client-by-client behaviour for font-stretch

Fully supports font-stretch (9): Gmail, Gmail iOS, Outlook 365, Outlook iOS, Outlook for Mac, Apple Mail, Apple Mail iOS, Thunderbird, Proton Mail.

No support (8): Gmail Android, Outlook (New), Outlook Android, Yahoo Mail, Yahoo Mail Android, Yahoo Mail iOS, Samsung Mail, AOL Mail. Plan fallbacks for these clients before relying on font-stretch in production sends.

Behaviour unverified in: Outlook Classic, HEY Mail, Fastmail, Superhuman.