box-sizing in Yahoo Mail iOS
Not supported box-sizing is not supported in Yahoo Mail iOS.
Works in 16 of 21 · not supported in 5
Which clients
- Works
- Gmail, Gmail Android, Gmail iOS, Outlook 365, Outlook (New), Outlook iOS, Outlook Android, Outlook for Mac, Apple Mail, Apple Mail iOS, Samsung Mail, Thunderbird, HEY Mail, Proton Mail, Fastmail, Superhuman
- Not supported
- Outlook Classic, Yahoo Mail, Yahoo Mail Android, Yahoo Mail iOS, AOL Mail
Your reader in Yahoo Mail iOS sees the email without box-sizing, even if it looks right where you tested it.
The fix for Yahoo Mail iOS
Account for padding in width manually (no box-sizing)
<div style="width: 300px;">
<div style="padding: 20px;">
Content; padding on inner element
</div>
</div>Show the original
<div style="width: 300px; padding: 20px;
box-sizing: border-box;">
Content; total width stays 300px
</div>The checker needs a computer screen.
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What Yahoo Mail iOS does with box-sizing
@emailens/engine 0.18.22 on the original code
Yahoo Mail iOS does not support "box-sizing".
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advice
Every feature in Yahoo Mail iOS · box-sizing in every client
Questions
- How many email clients support box-sizing?
- It works in 16 of 21, not supported in 5.
- What do I use instead of box-sizing in Yahoo Mail iOS?
- Account for padding in width manually (no box-sizing).
- Does box-sizing work in Yahoo Mail Android?
- box-sizing is not supported in Yahoo Mail Android. Closest to Yahoo Mail iOS: Yahoo Mail Android, which agrees on 284 of the 297 features both are tested on.
To see what else in your email Yahoo Mail iOS does not support, paste the whole email.
No signup · Five clients free, Outlook Classic included · All 21 with an account
The checker needs a computer screen.
Real captures 14 Oct 2026 on 11 installs · caniemail (MIT) via @emailens/engine 0.18.22 · tested upstream 28 Feb 2019 · data last changed 10 Nov 2026 · Outlook (New) cells are the engine's mapping