Top Free Spam Filters for Windows

Protect your inbox from spam, and incoming viruses and malware, with a good spam filter. Some of the best anti-spam filtering tools for Windows are completely free.

Try these free spam filters to rid your inbox of junk mail, and save your time and attention for more important matters.

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Screenshot of Spamihilator on Windows

Clayton Kroh

What We Like
  • Plenty of plug-ins available to expand functionality.

  • Clean interface not overcrowded with features.

What We Don't Like
  • No option to classify or categorize nonspam mail.

  • No support for remote web-based administration.

Spamihilator is an attractive, easy-to-use anti-spam tool that works with any email client and, thanks to Bayesian filters, has a good detection rate. It removes more than 98 percent of spam emails before they appear in your inbox. Spamihilator is highly configurable and works with both 32-bit and 64-bit Windows PCs.

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SpamExperts Dashboard.
What We Like
  • Flexible pricing plans.

  • Mobile friendly control panel.

What We Don't Like
  • Customer service operates on European time.

  • Sometimes marks non-spam as spam.

SpamExperts effectively identifies and eliminates spam, thanks to its real-time database and user synchronization. It works without additional configuration, and with any email program and just about any email account. SpamExperts can be deployed locally or run from the cloud while monitoring incoming and outgoing emails.

With its acquisition by SolarWinds MSP, SpamExperts gained an intuitive, easy-to-set-up user interface. Also as a result of the acquisition, SpamExperts is no longer free, but a free trial is available.

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K9 Spam filter.
What We Like
  • Advanced settings to track session statistics.

  • Add custom sound notifications.

What We Don't Like
  • No technical support.

  • Takes a little work to properly configure.

K9 is a wonderfully precise, easy-to-use, and fast-learning Bayesian spam filtering tool. It's a pity this gem only works with POP accounts and lacks remote administration. Although no longer in development, K9 still works well for many Windows users.

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G-Lock SpamCombat

Screenshot of G-Lock SpamCombat software

Clayton Kroh

What We Like
  • Deletes spam on server before you receive.

  • Easy to recover deleted messages.

What We Don't Like
  • Not available for Mac or Linux.

  • Full version requires you to buy license after 60 days.

G-Lock SpamCombat is a comprehensive and competent Bayesian spam filter that can make use of DNS blocklists. G-Lock SpamCombat uses the following email filters to prevent spam from making it to your inbox: Complex Filter, Safelist, Blocklist, HTML validator, DNSBL filter, and the Bayesian filter. This program works with POP3 and IMAP accounts.

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MailWasher Free

Screenshot of MailWasher software

Clayton Kroh

What We Like
  • Works well on iOS and Android.

  • Doubles as an email client.

  • View messages from multiple accounts at once.

What We Don't Like
  • Can't block messages based on country of origin.

  • Poor customer support.

MailWasher Free is a flexible, elegant, and effective spam filtering solution. MailWasher Free only works with one account and lacks the blocklist and server-based filtering found in MailWasher Pro; however, the free version lets you preview and delete emails on the server. This real-time spam filter service works with POP3, IMAP, AOL, Gmail, and other clients.

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Screenshot of SpamWeasel

What We Like
  • More features than most free alternatives.

  • Registration is no longer required.

What We Don't Like
  • Custom filters require programming knowledge.

  • No customer support beyond user manual.

With a full-fledged scripting language for filters, SpamWeasel is one of the more powerful free anti-spam tools. This easy-to-install filter works in a POP3 environment across any connection. Each message is ranked by the number of penalty points it accrues according to the program's rules. While the program works great out of the box, writing new filters isn't easy.

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