Most email providers accept between 20 MB and 25 MB of attachments per message, counting every file in the email together. Gmail, Yahoo Mail, Proton Mail and Outlook.com send 25 MB; iCloud Mail and personal Zoho Mail stop at 20 MB. Because email encodes attachments as text, the file you can actually attach is smaller still: about 18 MB on a 25 MB limit.
Limits by provider
| Provider | Send | Receive | Bigger files |
|---|---|---|---|
| Gmail (personal) | 25 MB | 50 MB (widely reported, not published by Google) | Google Drive link |
| Google Workspace Enterprise Plus | Up to 50 MB | 70 MB | Google Drive link |
| Outlook.com (personal) | 25 MB | 25 MB | OneDrive link up to 2 GB |
| Microsoft 365 (Exchange Online) | 35 MB default, up to 150 MB if the admin raises it | 36 MB default, up to 150 MB | OneDrive link |
| Yahoo Mail | 25 MB | 25 MB | Link from cloud storage |
| iCloud Mail | 20 MB | 20 MB | Mail Drop up to 5 GB, kept 30 days |
| Proton Mail | 25 MB (max 100 files) | 50 MB | Proton Drive link |
| Zoho Mail (personal) | 20 MB | 20 MB | Huge attachments on paid plans: 250 MB (Mail Lite) to 1 GB (Mail Premium) |
Yahoo, iCloud, Mail Drop, Proton and Zoho figures verified 2026-10-14, Gmail and Outlook figures verified 2026-10-13, on each provider's support page: Gmail, Outlook.com, Exchange Online limits, Yahoo Mail, iCloud Mail, Mail Drop, Proton Mail and Zoho Mail. Each provider has its own page with the details: see the Gmail attachment size limit and the Outlook attachment size limit.
Why does 25 MB turn into 33 MB?
Email was designed for text. To carry a photo or a PDF, your mail app converts the file to Base64 (the MIME encoding every provider uses), which represents every 3 bytes of the file with 4 characters. The result is about 33 percent bigger than the original, plus a little for headers.
Providers measure that encoded size. So a 25 MB file becomes roughly 33 MB in transit and a 20 MB file roughly 27 MB, and both fail a 25 MB check. A practical rule: divide the limit by 1.37 to get the largest file you can attach. That is about 18 MB on a 25 MB provider and about 14 MB on iCloud Mail or Zoho.
What happens when you go over the limit?
It depends on where the message fails.
- On your side, most webmail refuses the attachment or offers to upload it to the provider's cloud and insert a link. Gmail does this with Google Drive, Outlook with OneDrive, iCloud Mail with Mail Drop.
- On the recipient's side, the message leaves your outbox and comes back as a bounce, usually "552 message size exceeds maximum" or "message too large". The recipient's limit wins, so a 40 MB message from a Microsoft 365 account with raised limits still bounces at a Gmail address.
Zipping rarely helps. Photos, video and PDFs are already compressed, so a .zip saves a few percent at best. It does shrink documents, layered design files and folders of text.
How to send a file bigger than the limit
Send a link instead of an attachment. The file lives somewhere else and the email carries only the link, so no mailbox limit applies.
- Your provider's cloud. Google Drive, OneDrive, Mail Drop and Proton Drive all work, but the recipient sometimes needs an account or permission, and the link looks like a generic storage page.
- A transfer link. Brault Transfer uploads the files once and gives you a download link to paste into any email. Per-transfer caps by plan:
| Plan | Per transfer | Price |
|---|---|---|
| Free | 2 GB (5 transfers a month) | $0 |
| Lite | 50 GB | $4/mo, billed annually |
| Pro | 50 GB, unlimited, plus 100 GB transfers | $12/mo, billed annually |
| Growth | 250 GB | $70/mo, billed annually |
Every plan gets a branded download page. Lite and above can add a password, and Pro and above can set expiry from 7 to 180 days. The plans and limits page lists every cap.
For a longer walkthrough with every option compared, read how to send large files via email. If the file is going to a chat rather than an inbox, the Slack file size limit and the Google Drive file size limit cover those cases.