CSS Properties

white-space

CSS property · 14 supported, 4 partial, 3 unsupported across 21 clients

14 of 21 email clients render white-space fully (Sep 2, 2026 data); it breaks outright in Outlook (New), Outlook Classic, Samsung Mail.

7/7 webmail, 4/6 desktop, 3/8 mobile clients support white-space fully.
Unsupported in Outlook (New), Outlook Classic, Samsung Mail.
Partial in Gmail Android, Gmail iOS, Yahoo Mail Android, Yahoo Mail iOS, behavior differs from browsers, test before relying on it.
Outlook Classic (Word engine, supported to at least 2029) does not fully support white-space, 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 Feb 28, 2019, synced by Emailens Sep 2, 2026.

Client Support

Client	Category	Engine	Support
Gmail	webmail	Gmail Web	Supported
Gmail Android	mobile	Gmail Mobile	Partial^{See caveat 1}
Gmail iOS	mobile	Gmail Mobile	Partial^{See caveat 1}
Outlook 365	webmail	Outlook Web	Supported
Outlook (New)	desktop	Outlook Web	Unsupported
Outlook Classic	desktop	Microsoft Word	Unsupported
Outlook iOS	mobile	Outlook Mobile	Supported^{See caveat 2}
Outlook Android	mobile	Outlook Mobile	Supported^{See caveat 2}
Outlook for Mac	desktop	WebKit	Supported^{See caveat 2}
Apple Mail	desktop	WebKit	Supported
Apple Mail iOS	mobile	WebKit	Supported
Yahoo Mail	webmail	Yahoo	Supported
Yahoo Mail Android	mobile	Yahoo	Partial^{See caveat 2}
Yahoo Mail iOS	mobile	Yahoo	Partial^{See caveat 2}
Samsung Mail	mobile	Samsung	Unsupported
Thunderbird	desktop	Gecko	Supported
HEY Mail	webmail	WebKit	Supported
Proton Mail	webmail	Proton	Supported
AOL Mail	webmail	AOL	Supported
Fastmail	webmail	Fastmail	Supported
Superhuman	desktop	Blink	Supported

Documented caveats (2)

1.Gmail Android, Gmail iOS: Partial. Not supported with non Google accounts. Partial. pre value is not supported.
2.Outlook iOS, Outlook Android, Outlook for Mac, Yahoo Mail Android, Yahoo Mail iOS: Partial. pre value is not supported.

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

Client-by-client behaviour for white-space

Fully supports white-space (14): Gmail, Outlook 365, Outlook iOS, Outlook Android, Outlook for Mac, Apple Mail, Apple Mail iOS, Yahoo Mail, Thunderbird, HEY Mail, Proton Mail, AOL Mail, Fastmail, Superhuman.

Partial support (4): Gmail Android, Gmail iOS, Yahoo Mail Android, Yahoo Mail iOS. Expect rendering quirks unique to each engine. Partial support typically means a subset of values, an ignored shorthand, or sanitizer-specific rewrites.

No support (3): Outlook (New), Outlook Classic, Samsung Mail. Plan fallbacks for these clients before relying on white-space in production sends.