- What a colour category does, and what it doesn't
- Where to manage categories in each version
- How to assign and create categories in new Outlook
- How to create and rename a category in classic Outlook
- Classic Outlook extras worth setting up
- Categories on calendar events
- Seeing everything with one category
- My verdict on Outlook categories
- Frequently asked questions
Outlook categories are colour labels you put on emails, calendar events, contacts and other items so related things are easy to spot and group. You right-click an item, select Categorize and pick a category, and you can give the same item two or three categories by doing it again.
Here's the catch. If your email account is set up in Outlook as IMAP, you can't assign categories at all. Microsoft is blunt about it: the IMAP account type doesn't support categories. If the option is missing for you, check your account type before you go hunting through settings.
What a colour category does, and what it doesn't
Outlook starts you off with default categories that have generic names such as Red Category and Blue Category. You can rename them, change their colours or create your own. The colour shows in your inbox and inside the open item.
Two things Microsoft points out that most people never notice. Other people don't see the categories you assign, so they're your private filing system, not a message to anyone. And in the newer Outlook, the colour you pick is the colour of the category text, not the background of the label when it's applied.
Where to manage categories in each version
| Version | Assign | Rename or recolour |
|---|---|---|
| New Outlook for Windows | Right-click a message, or Categorize on the ribbon | Settings, Accounts, Categories, then Edit |
| Classic Outlook | Right-click a message, or Tags then Categorize | Tags, Categorize, All Categories, then Rename |
| Outlook on the web and Outlook.com | Right-click a message, or Categorize on the ribbon | Settings, Accounts, Categories, then Edit |
As of October 2026, Microsoft's two help pages on categories don't agree on renaming. The colour categories page shows an Edit option to rename one in new Outlook and on the web, while the use categories page says you can't rename them and should create a new one instead. If you don't see Edit, make a new category with the name you want and apply it before removing the old one.
How to assign and create categories in new Outlook
- Select the message or messages you want to label.
- Right-click and select Categorize, or select Categorize on the ribbon.
- Pick a category. Repeat to add a second or third.
- To make a new one, select Categorize, then New category.
- Type a name, choose a colour and select Save. It's created and applied to what you selected.
The Categorize list only shows your most recently used categories. If you can't see the one you want, select All categories or Manage categories at the bottom of the list. To remove one, clear the tick next to it. If you select several messages at once, the list only ticks the categories that are on every one of them.
How to create and rename a category in classic Outlook
- In any mail folder, under Tags on the ribbon, select Categorize, then All Categories.
- In the Color Categories box, select New.
- Type a name, choose a colour and, if you want, a shortcut key, then select OK.
- To rename one, select it in the Name list, select Rename, type the new name and select OK.
In the same box, tick a category before you select OK and Outlook applies it to whatever you've got selected in the main window. In the classic version of Outlook on the web, the route is different again: right-click a message, select Categorize, then Manage categories, where you can change a category's colour with the arrow next to it or select Delete to remove it.
Classic Outlook extras worth setting up
Classic Outlook has two time savers the newer versions don't list. The first is shortcut keys. Go to Tags, Categorize, All Categories, tick a category and choose a key from the Shortcut Key list. Select a message and press the key to apply that category, and it works on several items at once.
The second is the Quick Click category. In table views, for example with the reading pane turned off or moved under the message list, you get extra columns including Category. Set a Quick Click category through Tags, Categorize, Set Quick Click, and then one click in that column applies it.
Two more classic Outlook quirks. The first time you use one of the default categories, Outlook prompts you to rename it. And if you rename a category that's already in use, every item with it updates to the new name. If right-clicking a message only offers flag options, right-click in the blank space to the right of the sender's name instead.
Categories on calendar events
You can categorise calendar events the same way: right-click the event, select Categorize and pick one. There's a limit with recurring meetings, though. You can't put a category on a single instance of a series, only on the whole series. In classic Outlook, the Tags group sits on the Appointment or Meeting tab for calendar items.
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Seeing everything with one category
In new Outlook and on the web, open your Category list, select Add to Favorites for the category you want, and it appears in the Favorites folder list in your inbox. That gives you a one-click view of every message with that label.
My verdict on Outlook categories
Categories are the most flexible way to tag mail in Outlook because one email can sit in two or three groups at once, which folders can't do. I'd keep the list short, name them by client or job rather than colour, and set shortcut keys in classic Outlook for the ones you use daily. If you want labels applied without lifting a finger, use rules that run as mail arrives, and for the bigger system around them, here's how I organise an Outlook inbox.
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Frequently asked questions
Why can't I assign categories in Outlook?
If you use Outlook with an IMAP account, you can't assign categories. The IMAP email account type doesn't support categories.
Can other people see my Outlook categories?
No. Other people won't see the categories you assign.
Can I give an email more than one category?
Yes. Select Categorize again and pick another category. You can assign a second or third category the same way.
Can I categorise one meeting in a recurring series?
No. You can't apply a category to an instance of an appointment or meeting series, only to the entire series.
How do I set a shortcut key for a category in classic Outlook?
Select Tags, then Categorize, then All Categories, tick the category in the Name list and choose a key from the Shortcut Key list.
