Gmail filter actions
Gmail filter action Categorize as: Primary, Social, Promotions, Updates, or Forums.
Categorize as is the Gmail filter action for sending matching messages into a built-in category tab. It works when the sender, subject, or keyword pattern is known. It does not solve the broader unknown-sender problem, where every non-contact sender should leave the inbox automatically.
What does Categorize as do in a Gmail filter?
Categorize as is a Gmail filter action for messages that match criteria you define, such as a sender, subject line, keyword, or attachment. Instead of only labeling or archiving the message, the filter can place matching mail into a Gmail category tab.
Gmail categories are fixed destinations: Primary, Social, Promotions, Updates, and Forums. Use labels when you need custom names. Use KeepKnown when the routing rule is not a category at all, but the relationship rule: known contacts may interrupt the inbox, unknown senders should wait elsewhere.
Common Categorize as examples
- Promotions: route known newsletters, launch emails, discounts, and vendor campaigns away from Primary.
- Social: route notifications from social networks or media-sharing services.
- Updates: route receipts, confirmations, alerts, statements, and automated reminders.
- Primary: keep known people and messages that do not belong in other tabs in the main inbox.
- Forums: route group, board, and mailing-list conversations.
Where category filters stop
Category filters need a known pattern. Cold outreach, recruiter sprays, vendor pitches, and first-time strangers do not share one stable phrase. KeepKnown handles that broader case by checking whether the sender is in contacts, then moving outsiders to KK:OUTSIDERS without deleting the email.
Sources: Google Gmail categories help and Google Gmail filters help.
Short answer
Use Categorize as when a Gmail filter already knows what to match.
Create a Gmail filter, choose Categorize as, then select Primary, Social, Promotions, Updates, or Forums. Use this for known senders, newsletters, alerts, or phrases. Use KeepKnown when the real rule is sender not in contacts.
Which Gmail category should a filter use?
Primary
Best for people you know and messages that should remain in the main inbox.
Social
Use for social-network and media-sharing notifications that are not urgent inbox work.
Promotions
Use for newsletters, offers, launch emails, and vendor campaigns from known senders.
Updates
Use for confirmations, receipts, statements, reminders, and automated account notices.
Forums
Use for groups, discussion boards, and mailing-list conversations.
Unknown senders
Use KeepKnown when every non-contact sender should move out of the inbox without destructive blocking.
Inbox gate
Categories organize known mail. KeepKnown screens unknown mail.
Gmail categories are useful after a message matches a filter. KeepKnown is for the stricter rule Gmail does not expose: let contacts through and route everyone else to a recoverable outsider label.
Questions before you connect.
What does Categorize as do in a Gmail filter?
It sends messages matching that filter to a Gmail category tab such as Primary, Social, Promotions, Updates, or Forums.
Where is the Categorize as option in Gmail filters?
Create or edit a Gmail filter from the search options window, then choose the action the filter should take. Categorize as is one of the category-routing actions available for matching messages.
Can I create custom Gmail categories?
No. Gmail uses its current category tabs. Use labels for custom groupings, or KeepKnown for contact-based outsider screening.
Should I use Promotions, Social, Updates, or Primary?
Use Promotions for deals and campaigns, Social for network notifications, Updates for confirmations and alerts, and Primary for mail that should stay in the main inbox.
Is Categorize as the same as filtering senders not in contacts?
No. Categorize as routes messages that match a defined filter. It does not create a native sender-not-in-contacts rule.
How do I handle unknown senders Gmail cannot categorize reliably?
Use KeepKnown to compare each sender with your contacts. Known senders stay in the inbox; non-contact senders move to the recoverable KK:OUTSIDERS label.
Related inbox workflows
Gmail category filters
Organize known senders, then screen unknown senders automatically.