How can I send large files by email?

Email is designed for text messages; attachments are simply ‘attached’ to the email. For this reason, all mail servers impose a limit on the size of an email, and it is advisable to send large files as download links instead.

Why is there a file size limit for attachments?

Two servers determine this: the message must be accepted by both the sender’s and the recipient’s servers. If the limit is lower on either server, the message will not be delivered, and the sender will receive an error message such as ‘message size exceeds’.
The attachment in the email will be larger: the email client encodes the attached file as text (Base64), which increases its size by roughly a third. A 20 MB file will therefore result in an email of approximately 27 MB.
The limit varies by provider: major email service providers typically set it at around 20–25 MB, but a corporate server may accept even less than that.
Your mailbox is filling up: every large attachment takes up space both in the sender’s ‘Sent’ folder and in the recipient’s mailbox. We’ve written a separate article about how big your mailbox is and how you can free up space in it.

The simplest solution: upload the file to cloud hosting (Google Drive, OneDrive, Dropbox) or a file-sharing service (such as WeTransfer), and simply include the download link in your email.

Set who can open the link (anyone who has it, or only the specified recipients).
If possible, please specify an expiry date and delete the file after downloading it.
Gmail and Outlook themselves offer to upload attachments that are too large to their own cloud storage.

2. Uploading to your own storage space

If you have web hosting, you can upload the file to a separate folder using the file manager or SFTP, and then send the web address of that folder. Such a link is accessible to anyone who knows it, so:

Give the folder a name that is difficult to guess,
Protect it with a password; the steps for doing this in cPanel are described in our article on password-protecting directories,
Please delete the file after downloading it.

3. Compression

A ZIP or 7z archive combines many files into one and significantly reduces the size of text documents and spreadsheets. However, it offers little benefit for formats that are already compressed (JPG, MP4, PDF, DOCX). 7-Zip can split a large archive into several smaller volumes, but the recipient must receive every part and be able to extract them all; therefore, this is best used as a last resort.

4. For regular SFTP transfers

If you regularly exchange large files with a partner (print materials, videos, database backups), SFTP is the most reliable option: there are no size limits, interrupted transfers can be resumed, and the connection is encrypted. To do this, it is advisable to create a separate user account on the server with access to just one folder, whilst the partner will need an SFTP client program (such as FileZilla or WinSCP).

Confidential files

Do not post personal data, contracts or financial documents via a public link. Use a password-protected, encrypted archive (7-Zip with AES-256 encryption), and do not include the password in the same email; instead, provide it via a different channel, such as by telephone or text message.

Common errors

The recipient does not receive the email, and the sender does not notice the error message: if you have sent a large attachment, check to see if the email has been returned.
Expired or unauthorised link: please open the link in a private browser window before sending it.
Several large emails in quick succession: the recipient’s mailbox may become full and will no longer accept any further emails.

With our email hosting plans, you can choose from storage capacities ranging from 5 to 100 GB, so there’s plenty of space even for emails with attachments.