Email Alias vs New Mailbox: Save Licence Costs Without Chaos

Alias, shared mailbox, plus address or new mailbox?

Four tools cover nearly every 'we need another email address' request. They differ in cost, who can read the mail and what happens when people change.

For a paid mailbox, Microsoft 365 Business Basic was US$7 per user a month on an annual plan and Google Workspace Business Starter S$9.40 on the flexible plan, before GST, as of October 2026. Our business email cost guide has the full price table.

How email aliases work in Microsoft 365

Microsoft's guide to adding an email alias says you can create up to 400 aliases for a user, with no additional fees or licences. Mail to any alias lands in that user's inbox.

1. 1

   Open the user in the admin centre

   Go to Users, Active users, select the person. The alias option only appears if the user has a licence.

2. 2

   Add the alias

   Choose Manage username and email, type the new name, pick the domain and select Add, then Save changes. It can take up to 24 hours to work.

3. 3

   Let them send from the alias

   An admin can enable 'send from alias' for the organisation (SendFromAliasEnabled). Users then tick the alias in Outlook settings and pick it in the From field.

4. 4

   Test replies

   By default, Outlook on the web replies from the address the mail was sent to, while Outlook desktop replies from the primary address, per Microsoft. Check what your staff's app does.

Microsoft also points out that if several people need to manage mail sent to one address such as info@, you should create a shared mailbox rather than an alias.

How email aliases work in Google Workspace

Google's help page on adding an email alias says an admin can add up to 30 aliases for each user at no extra cost. Aliases are not Google Accounts: you cannot sign in with one, and only one user can receive mail at a given alias.

To send as the alias, the user adds it as a custom From address in Gmail settings ('Send mail as'). Google notes that several users can send from the same alias this way, but only one receives its mail. If several people need to receive and reply, Google recommends delegation or a group set up as a shared inbox instead.

Plus addressing: free extra addresses with no setup

Plus addressing adds a tag after a plus sign: jen+newsletters@yourdomain.com arrives in jen@'s inbox. It needs no admin work, and you can filter on the tag to see which sign-up leaked or sold your address.

Microsoft's plus addressing documentation says plus addressing is enabled by default in Exchange Online. Gmail and Google Workspace accept plus addresses too.

• Good for: supplier portals, newsletter sign-ups, testing website forms.
• Not for: addresses you print on name cards or give customers. Some websites reject the plus sign, and it looks odd.
• It is a receiving trick only. You still send from your normal address.

What happens when the person behind an alias leaves

This is where small businesses get caught. If sales@ is an alias on a salesperson's account, deleting that account deletes the alias, and enquiries start bouncing. If you leave the account active to keep sales@ working, you keep paying for a licence and a former employee's account stays open.

When someone leaves, the usual order is: move or remove their aliases, convert their mailbox (on Microsoft 365, to a shared mailbox) or add their old address as an alias on a current user (on Google Workspace), then release the licence. Our employee offboarding checklist covers the full sequence.

Shared mailboxes and groups for role addresses

For addresses several people answer, a shared mailbox (Microsoft 365) or a group set up as a collaborative inbox (Google Workspace) is the right tool. On Microsoft 365, a shared mailbox needs no licence up to 50 GB, and each person who opens it uses their own sign-in with MFA, so there is no shared password.

Our guide to shared mailbox vs group vs helpdesk explains the differences, including how to see who replied to a customer.

Do it yourself or get help?

Adding an alias takes a few minutes in either admin console. The work is in the clean-up: finding which accounts hold which addresses, moving role addresses to shared mailboxes or groups and checking that replies go out from the right address.

Our Business Email Setup (S$249) sets up your mailboxes, aliases and shared addresses on Microsoft 365 or Google Workspace, with sending tested from each one and a short record of who owns what.