← CSS Support Index

Does CSS margin-inline & margin-block Work in HTML Email?

Support for the `margin-inline` and `margin-block` shorthand properties.

Quick Answer

Does margin-inline & margin-block work in HTML email?

The CSS margin-inline & margin-block property is supported in Apple Mail, Thunderbird, ProtonMail, Fastmail. It is NOT supported in Gmail, Outlook (Windows), Outlook (Mac / Web), and others. Always include a safe fallback for unsupported clients.

Which Email Clients Support CSS margin-inline & margin-block?

CSS support for margin-inline & margin-block across email clients

Email ClientDesktopMobile / WebNotes
Gmail✗ No✗ No—
Outlook (Windows)✗ No?—
Outlook (Mac / Web)✗ No✗ No—
Apple Mail✓ Yes✓ Yes—
Yahoo! Mail✗ No✗ No—
Samsung Email?✗ No—
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
margin-inline & margin-block.

Open Email Previewer

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 margin-inline & margin-block can't sneak into your markup by accident. Open the Email Builder →