Gmail filter setup
Gmail filter actions: Categorize as, Mark as important, and apply filters.
Create Gmail filters for known sender or keyword patterns, then use KeepKnown for the stricter rule Gmail does not expose: only known contacts belong in the inbox.
How to create email filters in Gmail
- Open Gmail and click the search options icon in the search box.
- Enter criteria such as sender, recipient, subject, words, missing words, size, attachment, or date.
- Run the search first so you can confirm the rule catches the right messages.
- Choose Create filter, then select the actions Gmail should apply.
- Save the filter. Future messages that match the criteria will follow that rule.
Common Gmail filter actions
Gmail filters can apply labels, skip the inbox, mark mail as read, star it, forward it, delete it, keep it out of spam, mark it as important, categorize it, or apply the same rule to matching conversations already in the mailbox.
Useful email filter examples for Gmail
from:newsletter@example.com- label or archive one sender.subject:"invoice" OR subject:"receipt"- route invoice and receipt mail together.{invoice receipt statement}- match one of several related keywords.has:attachment filename:pdf- label PDF attachment mail.older_than:30d from:vendor@example.com- clean old mail from a known vendor.category:promotions- build a rule around Gmail category behavior.
How to apply Gmail filters to existing emails
When the same rule should clean up old mail, select the option to also apply the filter to matching conversations before creating it. This is useful for known newsletters, receipts, alerts, vendor notifications, and other repeatable patterns.
Where Gmail filters stop
Gmail filters need criteria you can describe in advance. They do not provide a native sender-not-in-contacts rule. KeepKnown fills that gap by checking senders against your contacts and routing outsiders to KK:OUTSIDERS without reading email bodies or deleting the message.
Sources: Google Gmail filters help and Google Gmail search operators help.
Short answer
How do I create email filters in Gmail?
Open Gmail search options, define sender, subject, phrase, recipient, date, attachment, size, or keyword criteria, choose Create filter, then select actions such as Apply label, Categorize as, Mark as important, Skip Inbox, or apply the filter to matching conversations.
Pick the Gmail filter action that matches the job
Organize known mail
Apply labels, categorize messages, star them, or mark trusted senders as important.
Keep the inbox cleaner
Skip the inbox, mark as read, or archive mail when a known pattern does not need immediate attention.
Clean existing mail
Apply the filter to matching conversations when the same rule should affect old Gmail messages too.
Use multiple keywords
Use exact phrases, OR conditions, and brace groups when several words should trigger the same rule.
Avoid fragile filters
Do not create dozens of one-off sender rules when the real pattern is simply unknown senders.
Screen unknown senders
Use KeepKnown when the rule is contact-based: known people stay visible, outsiders move out of the inbox.
Multiple keywords
Can Gmail email filters use multiple keywords?
Yes. Put exact phrases in quotes, combine alternatives with OR, or use braces like {invoice receipt statement}. Keyword filters still need explicit patterns; use KeepKnown when the real rule is whether the sender belongs in your contacts.
Inbox gate
Gmail filters organize known patterns. KeepKnown screens unknown senders.
Filters are best when you know the sender, phrase, or category. KeepKnown is for the recurring public-inbox problem: every non-contact sender should be moved away before it interrupts you.
Questions before you connect.
How do I create email filters in Gmail?
Open Gmail search options, enter criteria, test the search, choose Create filter, then select actions such as Apply label, Categorize as, Mark as important, Skip Inbox, or apply to matching conversations.
How do I create a filter in Gmail?
Use the search options icon in Gmail, enter criteria, run the search to confirm it matches the right messages, choose Create filter, select actions, and save the rule.
What actions can a Gmail filter take?
A Gmail filter can apply a label, archive mail, mark it as read, star it, forward it, delete it, keep it out of spam, mark it as important, categorize it, or apply the rule to matching conversations.
Can Gmail filters use multiple keywords?
Yes. Gmail filters use Gmail search syntax, so you can combine words, exact phrases, OR conditions, and brace groups such as {invoice receipt statement}.
How do I apply Gmail filters to existing emails?
When creating the filter, select the option to also apply it to matching conversations. Gmail then applies the selected actions to existing messages that match the criteria.
What does Categorize as do in a Gmail filter?
Categorize as sends matching email to one of Gmail's existing category tabs, such as Primary, Social, Promotions, Updates, or Forums.
Can Gmail filter senders not in my contacts?
Not natively. Gmail filters need explicit criteria. KeepKnown adds the contact-based rule by routing non-contact senders to a recoverable outsider label.
Related inbox workflows
Gmail filter setup
Find sender patterns Gmail filters are missing.