Email Attachment Size Limit
The maximum size limit for an email, including attachments, is approximately 20MB. However, this does not mean you can attach a 20MB file. Due to the nature of email transmission, there is about 17% inefficiency, which effectively reduces the maximum attachment size to around 15MB (total size of all attachments)
Comparison with Other Email Services
This limit is consistent with other major email services, such as:
- Outlook: Send large files with Outlook
- Google: Unable to send a message due to size limit on attachment
Sending and Receiving Rules
For an email to be successfully delivered, it must comply with the size limits of both the sender's and the receiver's email services. This also includes any intermediary email servers if email forwarding is involved.
Alternative Methods for Sharing Large Files
To share large files efficiently, consider using cloud storage services and sending a link to the file. Some recommended services include:
- Google Drive
- OneDrive
- Dropbox
Using these services ensures that large files are shared securely and efficiently without being hindered by email size limits.
More From This Section
There are several ways that email can be added/accessed on your domain name. Email forwarding, POP3 Mailbox Accounts, IMAP Mailbox Accounts, Google Suite/Apps, Microsoft Office 365, Server Name / MX Record change, Web Mail
You can now add new POP3 or IMAP email mailboxes directly through our CMS. Just click on the red email button under your domain name, then follow the directions
You can find your email mailbox settings via the DOMAINS / EMAILS button in the main menu.
Are you getting the following error message when sending a lot of emails from your desktop? "Recipient address rejected: Rate limit reach, retry later"
How to change your email password.
Known good settings for the Thunderbird Email Client
IMAP settings for the new Outlook for Windows (replacing Windows Mail) This is different to Outlook 365 - please see other help files.
Settings for Apple iOS / iPadOS products
How to set up your email on most Samsung phones.
Known settings for Gmail on Android
Outlook for Mobile is not compatible with our mail servers when trying to connect via a secure (SSL) connection.
Setting up email in the default OSX email client.
You should normally be able to let OSX detect the settings, but here are the settings shown in you uncheck Automatically manage connection settings.
We've setup our own iphones this way, works well, it uses the iphone/MS Exchange integration method, even though you are really using GMAIL or Google Apps.
Learn how to move away from xtra/yahoo/hotmail/etc to an awesome gmail experience
You can setup a mail account hosted with us in your standard Gmail account by linking it as a third party account
Do you have missing emails in your inbox? Have emails disappeared from your inbox?
Make sure you are using the incoming and outgoing mail servers provided by our instructions inside the CMS. Incoming: mail.cms-tool.net Outgoing: smtp.cms-tool.net
If you work from multiple locations or through different Internet Providers, then you may find changing your SMTP server all the time is a real hassle
How can i reduce/minimise the amount of spam I receive?
If some emails are not being delivered to you, find out what spam filtering is happening on our servers
How to set your 'reply to' address to your new personalised domain email address
You can have as many email aliases as you require, but limited pop mailboxes.
What is a forwarding email address and when do I need one?
Use this procedure to determine the problem with your email
Yes simply enter the two email addresses in the to field separated by semicolon and no spaces
There are lots of steps in email going from our web forms to your inbox, learn the process here if you are needing to debug email issues
if you have the ability to define SPF records or whitelist SMTP servers, please use include:spf.cms-tool.net
Copies all emails and folders from old IMAP server to new IMAP server
Learn about how we block spam, and how email may be blocked by other ISPs also.
If you should want to view your DMARC reports, here is how to find them
If you have email services with us, you can have an auto responder if you are away on holiday. Here's how.
May 2026 settings tested as working with the office365 desktop client. (This standalone app looks to have been replaced with a new app - see New Outlook guide above)
(This standalone app looks to have been replaced with a new app - see New Outlook guide above)
If you can connect to your mailbox but no mail is downloaded - see this troubleshooting tip. (This standalone app looks to have been replaced with a new app - see New Outlook guide above)
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