University of Southampton


Email plus-addresses in Office 365

The University email provider (Microsoft Office 365) now supports the use of "plus addressing". This allows you to use an unlimited number of addresses all delivered to your own mailbox. 

Plus addresses can be useful for testing purposes and as an easy way to create rules based on who you provided your email address to.

What is Plus addressing

Plus Addressing option allows you to create email addresses that are linked to a standard email address by adding a suffix to it. To create a Plus Address, add the “+tag” suffix to the local part of your email address. 

For example:

  • Your current email address looks like this: or
  • Plus Address can be:,,

You can use plus addresses as unique addresses for services that you sign up for. Please note that some web forms do not support plus signs in email addresses.

How it works

With plus addressing you can append any valid email text (generally anything except the @ symbol) after the first part of your address joined with a "+" character.

Plus Addressing delivers the Plus email to the standard address because:

  • It treats the “+” (plus) sign as a special indicator
  • It ignores everything on right to the “+” sign (for routing purpose)

Any emails sent to these addresses (for example: will be delivered to the standard mailbox (for example: 

When it’s useful to create a Plus Address

Plus Addressing is useful when you:

  • Want to sign-up to companies’ forms or mailing list, using plus addresses as unique addresses
  • Want to create a rule for messages sent to a specific plus address. Using email rules, you can move those messages to a specific folder regardless of who is emailing you
  • Helps you to identify when a website sold or accidentally leaked your email address to a spammer. You can use the inbox rule to identify mails sent to the compromised address and block them.

An example

You are signing up to a web site that insists on having your email address but you suspect they might give your address to spammers. You can give them an address like "", then add an Outlook rule to send all email to that address into the spam folder.

Useful links

To see all the aliases and to set your primary email address, log into Subscribe

Technical information is available at Microsoft Documentation - Plus Addressing

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