Gmail filter how-to

How to create email filters in Gmail without missing the real gap.

Use Gmail filters for known senders, words, labels, categories, and actions. Use KeepKnown when the filter you actually need is sender not in contacts.

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Create filterApply labelsSkip InboxScreen unknown senders

KeepKnown screening unknown Gmail senders while Gmail filters handle known rules

How to create a Gmail filter

Open Gmail on a computer.
Click the search options icon in the search box.
Enter criteria such as sender, recipient, subject, words, missing words, size, attachment, or date.
Use Search first to confirm the rule matches the right messages.
Click Create filter, choose the actions, then save the filter.

Useful email filter examples

from:newsletter@example.com - label or archive one sender.
subject:"invoice" OR subject:"receipt" - group invoice and receipt mail.
{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 a Gmail category.

Where Gmail filters stop

Gmail filters work when you can describe the rule in advance. They can label, archive, star, forward, delete, categorize, or mark matching mail as important. They do not provide a native rule for every sender who is not in Google Contacts.

KeepKnown fills that gap by using your contacts as the allow-list. Known senders stay visible, and unknown senders move to KK:OUTSIDERS without deleting mail or reading message bodies.

Source: Google Gmail filters help.

Short answer

Create Gmail filters from search options, then choose actions.

Open Gmail search options, enter criteria, test the search, click Create filter, then choose actions such as Apply label, Skip Inbox, Mark as important, Categorize as, or apply to matching conversations.

Use the right tool for each filtering job.

Known patterns

Use Gmail filters for exact senders, subjects, keywords, attachments, categories, labels, and date rules.

Existing mail

Apply a filter to matching conversations when the same rule should clean up old email too.

Unknown senders

Use KeepKnown when the rule is contact-based: people you know pass, outsiders move out of the inbox.

Questions before you connect.

How do I create email filters in Gmail?

Open Gmail search options, enter criteria, check the search results, click Create filter, choose the actions, and save the rule.

Can Gmail filters apply to existing emails?

Yes. When creating a filter, choose the option to apply it to matching conversations if you want the rule to clean up old mail as well as future mail.

Can Gmail create a filter for everyone not in my contacts?

Not natively. Gmail filters require criteria such as sender, words, subject, labels, or categories. KeepKnown adds contact-based screening for non-contact senders.

What should a Gmail filter do with unknown senders?

If the rule is just one known sender or phrase, Gmail filters are enough. If the rule is every sender outside your contacts, KeepKnown routes those outsiders to a recoverable label automatically.

Related inbox workflows

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