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Does CSS aspect-ratio Work in HTML Email?
Sets a preferred aspect ratio for the element
Quick Answer
Does aspect-ratio work in HTML email?
The CSS aspect-ratio property is supported in Apple Mail, ProtonMail. 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 aspect-ratio?
CSS support for aspect-ratio across email clients
| Email Client | Desktop | Mobile / Web | Notes |
|---|---|---|---|
| Gmail | ✗ No | ✗ No | — |
| Outlook (Windows) | ✗ No | ? | — |
| Outlook (Mac / Web) | ✗ No | ✗ No | — |
| Apple Mail | ✓ Yes | ✓ Yes | — |
| Yahoo! Mail | ✗ No | ✗ No | — |
| Samsung Email | ? | ✗ No | — |
| Thunderbird | ✗ No | ? | — |
| ProtonMail | ✓ Yes | ✓ Yes | — |
| Fastmail | ✗ No | ? | — |
Notes
- #1 Requires iOS 15.
Frequently Asked Questions
Related CSS Properties
Test Your Email Now
Paste your HTML and see how it renders in clients that don't support aspect-ratio.