width
CSS property · 20 supported, 1 partial, 0 unsupported across 21 clients
width is safe in 20 of 21 email clients as of Sep 2, 2026, the holdout is Outlook (New).
- 7/7 webmail, 5/6 desktop, 8/8 mobile clients support width fully.
- Partial in Outlook (New), behavior differs from browsers, test before relying on it.
- 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 27, 2019, synced by Emailens Sep 2, 2026.
Client Support
| Client | Category | Engine | Support |
|---|---|---|---|
| Gmail | webmail | Gmail Web | Supported |
| Gmail Android | mobile | Gmail Mobile | Supported |
| Gmail iOS | mobile | Gmail Mobile | Supported |
| Outlook 365 | webmail | Outlook Web | Supported |
| Outlook (New) | desktop | Outlook Web | PartialSee caveat 1 |
| Outlook Classic | desktop | Microsoft Word | Supported |
| Outlook iOS | mobile | Outlook Mobile | Supported |
| Outlook Android | mobile | Outlook Mobile | Supported |
| Outlook for Mac | desktop | WebKit | Supported |
| Apple Mail | desktop | WebKit | Supported |
| Apple Mail iOS | mobile | WebKit | Supported |
| Yahoo Mail | webmail | Yahoo | Supported |
| Yahoo Mail Android | mobile | Yahoo | Supported |
| Yahoo Mail iOS | mobile | Yahoo | Supported |
| Samsung Mail | mobile | Samsung | Supported |
| 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 (1)
- 1.Outlook (New): Partial. Not supported on
<body>,<span>,<div>,<p>or<img>elements.
Caveats recorded by caniemail.com (MIT) and carried verbatim, one entry per wording rather than per client.
Client-by-client behaviour for width
Fully supports width (20): Gmail, Gmail Android, Gmail iOS, Outlook 365, Outlook Classic, 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.
Partial support (1): Outlook (New). Expect rendering quirks unique to each engine. Partial support typically means a subset of values, an ignored shorthand, or sanitizer-specific rewrites.
Fixes & Workarounds
Outlook (New)
Partial"width" is not supported in this email client.
Related Features
Check your own HTML for width
Paste your own, or run the sample below. Analyzed in this page, with no signup and nothing stored.
Test your width layout across 21 email clients
Preview rendering, catch CSS issues, and see how width displays across Outlook, Gmail, and Apple Mail. Free, no account needed.
Instant live preview · No signup required · 21 email engines
Last tested upstream: · Last synced by Emailens:
caniemail.com (MIT) records Sep 27, 2019 as the last time width was tested in a real client, 6 years before this sync. Syncing copies that result forward, it does not re-test it. Carried in @emailens/engine data v0.12.2.