Top Free Spam Filters for Windows

Mailbox filled full with letters and junk mail
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Protect your inbox from spam -- and incoming viruses and malware -- with a spam filter. Some of the best anti-spam filtering tools for Windows are completely free. Use one of them to rid your inbox of all the junk mail efficiently, and save your time and attention for more important matters.


Screen shot of the Spamihilator on Windows


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 arrive in your inbox. Spamihilator examines every incoming email and filters spam out. The program is highly configurable and works with both 32-bit and 64-bit Windows PCs.


Screenshot of eXpurgate
Heinz Tschabitscher

Spamfence is an effortless but highly effective spam and virus filtering service. It uses eXpurgate -- the service behind Spamfence -- to protect your inbox. Its only real shortcoming is that Spamfence relies on forwarding and requires two different email accounts.


Screenshot of SpamExperts software


SpamExperts identifies and eliminates spam precisely, thanks to its real-time database and user synchronization. It works without additional configuration, with any email program, and just about any email account. The program can be deployed locally or in the cloud, and it monitors incoming and outgoing emails. With its recent 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.


Screenshot of K9 Spam Filter
Heinz Tschabitscher

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 it is no longer in development, it still works well for many Windows users.

G-Lock SpamCombat

Screenshot of G-Lock SpamCombat software


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

MailWasher Free

Screenshot of MailWasher software


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


Screenshot of SpamWeasel


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

Cactus Spam Filter

Screenshot of Cactus Spam Filter


Cactus Spam Filter is an easy-to-use and precise spam filter that only works with POP3 accounts. When you download and install the Cactus Spam killer, it starts protecting your inbox right away. No additional settings in your email client are necessary. Cactus Spam Filter is compatible with Windows 7 and older operating systems.