How to use plus addressing

Managing your inbox doesn’t have to be a headache. Whether you're signing up for newsletters, testing email forms, or just want more control over your email flow, plus addressing is a handy feature that can make life easier.

This tech tip will walk you through how it works and how to use it effectively, especially if you're using Microsoft 365 or Outlook.

What is Plus Addressing?

Plus addressing (also known as subaddressing) is a feature that allows you to create unlimited custom email addresses using a “+” sign without needing to create new accounts or aliases.

Let’s say your email address is:

john.smith@example.co.uk

With plus addressing, you can use:

john.smith+1@example.co.uk 

john.smith+test@example.co.uk 

john.smith+app@example.co.uk 

Emails sent to any of those addresses will still land in your regular inbox, but you’ll see exactly which version of your address was used. This is incredibly useful for sorting, filtering, and tracking.

Why use it?

Here are a few practical reasons:

• Organisation: set up inbox rules based on the “+tag” to move messages into specific folders.
• Testing: quickly generate multiple test email addresses for form submissions, workflows, or user scenarios, all delivered to a single inbox.
• Track sign-ups: know exactly which website or service sold or shared your email address.
• Custom filters: easily block or redirect unwanted messages from a particular tag.
• No extra setup: no need to create multiple aliases or accounts.

How to get test email addresses

Need a few different email addresses for testing, but don’t want to create separate accounts? Plus addressing has this covered.

Simply take your normal email and add a unique tag after the plus sign. For example:

firstname.surname+form1@yourdomain.co.uk   

firstname.surname+form2@yourdomain.co.uk 

This is perfect for developers testing email forms, workflows, or filtering rules. It’s also ideal when you want to simulate different user submissions to the same inbox.

This approach saves time and ensures all your test responses end up in one place, while still allowing you to distinguish between them.

Note: if you’re using Exchange Online or Microsoft 365, plus addressing is supported by default, but your organisation’s admin may need to confirm it’s enabled. Check Microsoft’s official guidance here: enable plus addressing in Exchange Online. Once enabled, just start using plus addresses as needed. No setup required on your part.

Things to keep in mind

• Some older websites may reject emails with a “+” symbol, so it’s not foolproof everywhere.
• Be consistent in your tagging to keep filters tidy and meaningful.
• You can create inbox rules in Outlook or Exchange to automatically sort messages based on the tagged address.