Maximum Attachment Size
Our servers have a large attachment size limit, to allow you to send large files if necessary.
The limit is in place to prevent our service's resources from being tied up with extremely large emails being sent.
The maximum size limit per email is 50MB.
Keep in mind that if you are sending an attachment, your email will be larger than the file system reported size:
- Attachments grow by about 40% when encoded using Base64.
- Attachments grow by a variable amount (0-220%) when encoded with Quoted-Printable, depending on how much is ASCII and how much is not.
Please note that we don't generally recommend that you use email to send files larger than about 10MB, as there are better ways to send large attachments. A free service such as Tresorit can let you upload very large files reliably (they also have paid plans that make things easier). You can then easily email a simple link to the file you have uploaded to your recipient.
Note that the API sending limit is set to 10MB total.