Quick answer: Proton Mail's limit is 25 MB per email. Outgoing attachments in total; incoming messages can carry up to 50 MB, and up to 100 files. For anything bigger, send a download link: Share Large Video Files takes up to 20 GB per transfer, free and without an account.
The Proton Mail limit
| Account | Limit | Details | Checked |
|---|---|---|---|
| Proton Mail | 25 MB per email | Outgoing attachments in total; incoming messages can carry up to 50 MB, and up to 100 files. Source | Sep 2026 |
Email encodes attachments before sending, which makes them about a third larger. A file just under the limit can still be refused.
What happens when a file is too big
Your email app refuses to send the message, or the attachment is swapped for a cloud-storage link. The recipient's provider can also reject a message that your provider accepted, because its limit may be lower.
How to send a bigger file with Proton Mail
Send a download link instead of the file. The link is short text, so it fits in any email:
- Open Share Large Video Files in any browser and choose Get a link (or Send by email).
- Drop the file on the upload box, or pick a whole folder. Up to 20 GB and 1000 files per transfer.
- Optional: add a password, a download limit or an expiry under More options.
- Copy the link (or show the QR code) and send it by chat or email. The recipient downloads the original file, byte for byte.
Compared with other email providers
| App | Limit |
|---|---|
| Gmail | 25 MB per email |
| Outlook.com | 20 to 25 MB per email |
| Outlook / Exchange Online (work accounts) | 35 MB to send, 36 MB to receive (default) |
| Yahoo Mail | 25 MB per email |
| iCloud Mail | 20 MB per email (5 GB with Mail Drop) |
| Share Large Video Files | 20 GB per transfer, free |
Frequently asked questions
What is the Proton Mail attachment size limit?
Proton Mail: 25 MB per email. Outgoing attachments in total; incoming messages can carry up to 50 MB, and up to 100 files.
How do I send a file larger than the Proton Mail limit?
Upload it to Share Large Video Files (up to 20 GB, free, no account) and paste the download link into Proton Mail. The recipient gets the original file.
When was this limit checked?
On September 29, 2026, against Proton Mail's own help pages (linked in the table). Services change their limits, so follow the source link if your file is close to it.
Which apps accept bigger files than Proton Mail?
Of the email and chat apps we track: Microsoft Teams (chat) (250 GB per file), Telegram Premium (4 GB per file), WhatsApp (document) (2 GB per file), Telegram (2 GB per file), Slack (1 GB per file). Cloud drives and transfer services go much higher; Share Large Video Files takes up to 20 GB per transfer, free.
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