← CSS Support IndexDoes CSS
Does CSS border-radius Work in HTML Email?
The `border-radius` CSS property rounds the corners of an element's outer border edge.
Quick Answer
Does border-radius work in HTML email?
The CSS border-radius property is supported in Gmail, Outlook (Mac / Web), Apple Mail, Samsung Email, and others. It is NOT supported in Outlook (Windows). Always include a safe fallback for unsupported clients.
Which Email Clients Support CSS border-radius?
CSS support for border-radius across email clients
| Email Client | Desktop | Mobile / Web | Notes |
|---|---|---|---|
| Gmail | ✓ Yes | ✓ Yes | — |
| Outlook (Windows) | ✗ No | ? | — |
| Outlook (Mac / Web) | ✓ Yes | ✓ Yes | — |
| Apple Mail | ✓ Yes | ✓ Yes | — |
| Yahoo! Mail | ~ Partial | ~ Partial | — |
| Samsung Email | ? | ✓ Yes | — |
| Thunderbird | ✓ Yes | ? | — |
| ProtonMail | ✓ Yes | ✓ Yes | — |
| Fastmail | ✓ Yes | ? | — |
Notes
- #1 Round corners can be used in VML with the `RoundRect` element. See [buttons.cm](https://buttons.cm/) and [VML documentation](https://docs.microsoft.com/en-us/windows/win32/vml/msdn-online-vml-roundrect-element).
- #2 Partial support. Shorthand for setting elliptical borders with the slash `/` notation is not supported e.g. `border-radius: 27% 73% 70% 30% / 30% 34% 66% 70%;`.
Frequently Asked Questions
Related CSS Properties
Test Your Email Now
Paste your HTML and see how it renders in clients that don't support border-radius.
Building a new email instead of checking an existing one? MailViewr's Email Builder only lets you use CSS that's known to render across clients, so border-radius can't sneak into your markup by accident. Open the Email Builder →