How to Use Categories in Outlook (Colour-Code Your Emails and Calendar)
Folders are good for putting things away. Categories are good for seeing what things are. An email can be in one folder but carry two or three categories — "Client", "Urgent", "Invoice" — each with its own colour. The same categories work on calendar events and contacts, so your whole week is colour-coded at a glance.
Quick reference
| What you want | How |
|---|---|
| Tag an email | Right-click → Categorize → pick a colour |
| Make a new category | Categorize → New category (or All Categories) |
| Rename a colour | Settings → General → Categories (new) / All Categories → Rename (classic) |
| See everything in one category | Search category:Client or filter by category |
1. Apply a category to an email
1. Right-click the email (or select it and look for Categorize on the toolbar).
2. Choose Categorize.
3. Click a category.
2. Choose Categorize.
3. Click a category.
The colour appears next to the subject in your message list. Repeat to add more than one category; click a category again to remove it.
2. Create your own categories
The default categories are just colours called "Red category", "Blue category" and so on. Give them real names:
New Outlook and Outlook on the web:
1. Click Settings → General → Categories.
2. Click Create category, type a name and pick a colour.
3. Click Save. To rename a colour, click its pencil icon.
2. Click Create category, type a name and pick a colour.
3. Click Save. To rename a colour, click its pencil icon.
Classic Outlook:
1. Click Categorize → All Categories…
2. Click New…, type a name, choose a colour and click OK.
3. Select an existing one and click Rename to change it.
2. Click New…, type a name, choose a colour and click OK.
3. Select an existing one and click Rename to change it.
Good categories describe why something matters, not where it came from: Action, Waiting, Client A, Personal, Receipts.
3. Colour-code your calendar
Open any event, click Categorize (new Outlook) or the Categorize button on the ribbon (classic) and pick a category. The event changes colour on your calendar. Apply Personal to anything that's not work and you'll see your week's balance instantly.
Recurring events take the category on every occurrence.
4. Find everything in a category
• New Outlook — click Filter above the message list and choose Categories, or type category:Client in the search box.
• Classic Outlook — click Filter Email → Categorized, or click the Categories column heading to sort by category.
• Classic Outlook — click Filter Email → Categorized, or click the Categories column heading to sort by category.
Categories survive moving between folders, so you can file an email away and still find it as part of a project.
5. Apply a category with one click
Classic Outlook: click Categorize → Set Quick Click… and choose a category. From then on, clicking the empty category column next to any email applies it instantly.
New Outlook: add Categorize to the toolbar via Customize actions, and pin your favourite categories to the top of the list by hovering over them and clicking the pin.
6. Let a rule do the tagging
Right-click an email from your most important client, choose Rules → Create rule, and set the action to Categorize. Every future email from them is tagged before you even see it.
Troubleshooting
Categories don't show on my phone. The Outlook mobile app shows category colours but can't apply them. Tag on your computer; the colours sync.
My categories disappeared on another computer. Categories live in your mailbox and sync for Microsoft 365, Exchange and Outlook.com accounts. For Gmail or IMAP accounts added to Outlook, they stay on the computer where you made them.
The colours are hard to tell apart. Use fewer categories. Five or six distinct colours are plenty — beyond that, nobody remembers what olive green means.
Wrapping up
Name five or six categories, colour your calendar with them, and set a Quick Click for the one you use most. It's the quickest way to make an inbox and a diary make sense at a glance.
