CSS Properties

margin

CSS property · 9 supported, 12 partial, 0 unsupported across 21 clients

margin controls external spacing around block-level elements and is notably less reliable in email than padding. Outlook on Windows ignores margin on most elements, so production email layouts typically substitute margin with padded <td> cells. Modern clients honor margin correctly, but the lowest-common-denominator approach is to avoid it entirely for structural spacing.

Client Support

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

Client-by-client behaviour for margin

Fully supports margin (9): Outlook for Mac, Apple Mail, Apple Mail iOS, Samsung Mail, Thunderbird, HEY Mail, Proton Mail, Fastmail, Superhuman.

Partial support (12): Gmail, Gmail Android, Gmail iOS, Outlook 365, Outlook (New), Outlook Classic, Outlook iOS, Outlook Android, Yahoo Mail, Yahoo Mail Android, Yahoo Mail iOS, AOL Mail. Expect rendering quirks unique to each engine. Partial support typically means a subset of values, an ignored shorthand, or sanitizer-specific rewrites.

When to use margin in email

Centering an outer table by setting margin: 0 auto on the table element when targeting modern clients only.
Adding small gaps between inline-block elements in mobile-first templates.
Resetting default margins on block elements like <p>, <h1>, and <ul> via inline overrides.

Rendering behaviour and edge cases

Outlook on Windows ignores margin on table elements, breaking centering tricks unless you use align="center" and a fixed width.
Gmail strips negative margin values entirely, making margin-based off-canvas tricks unreliable.
Some clients add extra default margin on <p> tags , explicitly set margin: 0 on every paragraph that needs predictable spacing.

Recommended fallback strategy

Replace structural margin with padded table cells for cross-client consistency. Use margin only for resetting browser defaults on block elements, and always set explicit margin: 0 on <p>, <h1>–<h6>, and <ul> to prevent client-default spacing from pushing your layout.