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Does CSS em unit Work in HTML Email?
Support for em unit, relative to the current font-size.
Quick Answer
Does em unit work in HTML email?
The CSS em unit property is supported in all major email clients tested. You can use it with confidence in your HTML emails.
Which Email Clients Support CSS em unit?
CSS support for em unit across email clients
| Email Client | Desktop | Mobile / Web | Notes |
|---|---|---|---|
| Gmail | ✓ Yes | ✓ Yes | — |
| Outlook (Windows) | ✓ Yes | ? | — |
| Outlook (Mac / Web) | ✓ Yes | ✓ Yes | — |
| Apple Mail | ✓ Yes | ✓ Yes | — |
| Yahoo! Mail | ✓ Yes | ✓ Yes | — |
| Samsung Email | ? | ✓ Yes | — |
| Thunderbird | ✓ Yes | ? | — |
| ProtonMail | ✓ Yes | ✓ Yes | — |
| Fastmail | ✓ Yes | ? | — |
Frequently Asked Questions
Related CSS Properties
Test Your Email Now
Paste your HTML and see how it renders in clients that don't support em unit.