CSS property · data last changed 10 Nov 2026
font-size-adjust in email clients
Works in 10 of 21. Not supported in Outlook Classic. Partial in Gmail Android, Gmail iOS, Yahoo Mail and 2 more. Untested in Samsung Mail, HEY Mail, AOL Mail and 2 more.
Your reader in Outlook Classic sees the email without font-size-adjust, even if it looks right where you tested it.
caniemail (MIT) via @emailens/engine 0.18.22
What to do instead in Outlook Classic
There is no drop-in fix for font-size-adjust in Outlook Classic. Design so the email still reads without it.
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font-size-adjust is not among the 24 features we have screenshotted on real installs. The ones we have →
All 21 clients, problems first
| Client | Support |
|---|---|
| Outlook Classic | Not supported |
| Gmail Android | Partial See caveat 1 |
| Gmail iOS | Partial See caveat 1 |
| Yahoo Mail | Partial See caveat 2 |
| Yahoo Mail Android | Partial See caveat 2 |
| Yahoo Mail iOS | Partial See caveat 2 |
| Samsung Mail | Untested |
| HEY Mail | Untested |
| AOL Mail | Untested |
| Fastmail | Untested |
| Superhuman | Untested |
Works in 10: Gmail, Outlook 365, Outlook (New) and 7 more. Show all
| Client | Support |
|---|---|
| Gmail | Works |
| Outlook 365 | Works |
| Outlook (New) | Works |
| Outlook iOS | Works |
| Outlook Android | Works |
| Outlook for Mac | Works |
| Apple Mail | Works |
| Apple Mail iOS | Works |
| Thunderbird | Works |
| Proton Mail | Works |
Caveats (2)
- 1. Gmail Android, Gmail iOS: Not supported with non Google accounts.
- 2. Yahoo Mail, Yahoo Mail Android, Yahoo Mail iOS: 2-value syntax is supported, but the first value (font-metric) is ignored.
Caveats as recorded by caniemail (MIT), one entry per wording.
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