Best Free Spam Filter for Experienced Users


Many spam filters are available employing lots of different techniques. In my experience "learning" spam filters that use the Bayesian statistical approach out-perform most other types of filters. Not only are they better at detecting spam, they are also less liable to classify your real mail as spam.

This effectiveness takes a little time to develop as the filter has to be trained to recognize your spam from your normal mail. It takes a week or so before results start becoming accurate and best results may take a month or more.

As this is designed for experienced users, I will give a tip that might be confusing for average users: Is it really a spam, or a service site you signed up for and don't want anymore?

Take a look at the e-mail and if it is from a company you ordered something from or signed up to receive e-mail from, then it may be something you don't want, but is not really spam. If so unsubscribe from the site itself. Say if the e-mail is from and you ordered from them, go to the site and unsubscribe to the newsletter etc. If it is "legitimate" spam don't click the unsubscribe link.

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POPFile was one of the first Bayesian filters and is still one of the best. It works as a proxy mail server so that it can be used with any POP email client. Setup is reasonably straightforward for experienced users but beginners may be better off with Mailwasher.


Spamato is a promising, free open source spam filter with a difference. Rather than rely on one Bayesian spam filter to classify spam, Spamato uses a "multifaceted spam filter system that combines a variety of anti-spam techniques". Like POPFile, it can work with any email client but additional plugins are available to integrate Spamato into Outlook, Thunderbird and the Mozilla Mail Client.


Other excellent free Bayesian spam filters available include SpamBayes and K9. Both are simple to install, though like all statistical filters, they need to go through a training phase before they reach full effectiveness.

A newer addition to this list is Spam Terrier from Agnitum. If you are new to Bayesian spam filters and use Outlook, you will find this program is a tad easier to install and use than SpamBayes or K9.


Other spam filters to be reviewed:

Spamihilater, Ella, Email remover, eXpurgate, SpamPal, Epam Experts Desktop, Cactus Spam Filter, SpamRIP, Bullguard Spam Filter, G-Lock Spam Combat, SpamWeasel, GMail Service.

If you have any experience with any of these, please feel free to share that info in the forum or give your comments at the end of this article.

Related Products and Links

You might want to check out these articles too:

Quick Selection Guide

Gizmo's Freeware award as the best product in its class!

Runs as a stand-alone program on a user's computer
Works as a proxy mail server, can be used with any POP email client. Setup is reasonably straightforward for experienced users.
Beginners may be better off with Mailwasher.
6.16 MB ZIP
Unrestricted freeware
Windows 95, 98, Me, NT, 2000, XP, Vista, Mac OS, Linux, Unix

Additional Software Required: Requires Perl and Microsoft Outlook or Outlook Express. Supports the following protocols: POP3, SSL POP3, IMAP, HTTP (MSN, Yahoo, AOL), Exchange (with Outclass extension).

Runs as a stand-alone program on a user's computer
Uses a “multifaceted spam filter system that combines a variety of anti-spam techniques”. Like POPFile, it can work with any email client.
Requires additional plugins to integrate Spamato into Outlook, Thunderbird and the Mozilla Mail Client.
4.97 MB
Unrestricted freeware
Windows NT, 2000, XP, Vista, Mac OS, Linux

Additional Software Required: Java 5 (JRE) Environment or higher, .NET Framework 1.1 or higher (if using Outlook plugin in Windows). Supports the following protocols: POP3, IMAP.

Runs as a stand-alone program on a user's computer
Simple to install.
Like all statistical filters, need to go through a training phase before reaching full effectiveness.
10.3 MB
Unrestricted freeware
Windows 98, Me, NT, 2000, XP, Vista, Mac OS, Linux, Unix

Supports the following protocols: POP3, IMAP

Runs as a stand-alone program on a user's computer
Simple to install.
Like all statistical filters, need to go through a training phase before reaching full effectiveness.
113 KB
Unrestricted freeware
Windows 95, 98, Me, NT, 2000, XP

Supports the following protocols: POP3

Spam Terrier
Runs as a stand-alone program on a user's computer
Outlook users will find this program is a tad easier to install and use than SpamBayes or K9.
More suitable for Outlook users only.
2.1 (341)
1.65 MB
Unrestricted freeware
There is no portable version of this product available.
Windows 98, Me, 2000, XP, Vista, 2003 Server, 2008 Server

Additional Software Required: Requires Microsoft Outlook or Outlook Express. Supports the following protocols: POP3, SSL POP3, IMAP, HTTP (MSN, Yahoo, AOL), Exchange.


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by Anonymous on 1. November 2008 - 15:27  (9932)

Is it possible that this section could be expanded to include web browser ad block apps?

by Anonymous on 25. December 2008 - 15:46  (12447)

gmail.... any spam filter can filter out all the spam, trouble is that only a few like gmail can avoid to put almost any legitimate mail in the spam box.

Having to work through your spam box on a regular basis completely defeats the purpose of a spam filter. Therefore, if you can't use something like gmail then I would suggest getting a weaker spam filter that lets some spam through but doesn't mark good mail as spam. This is especially important if you run a business or use email for work.

I would avoid any spam filter that uses bayesian filtering like the plague (so probably most of them). I would go with gmail or there was some spam proxy, forget the name, that worked on a central database of spam messages. That is the best way to implement a spam filter, by letting users flag what is spam so that other users may benefit.

by Anonymous on 10. February 2009 - 14:09  (15735)

I installed spamato on outlook and it does a great job of filtering spam but it is a huge memory hog. I do not recommend it.

by Anonymous on 11. March 2009 - 7:43  (17596),2845,2342378,00.asp

your views gizmo?

is spam fighter better than the other 2?

wish to rely on you as the final authority without having to compare other reviews.

by Anonymous on 22. March 2009 - 18:36  (18331)

I just wanted to take a moment to thank you for turning me on to Spam Terrier. What a GREAT little app and very easily integrated into Outlook Express as a plug-in. Nice!

by Anonymous on 22. April 2009 - 1:32  (20290)

Spamato takes 700K of RAM. It worked well, but I couldn't keep Outlook open with it installed. Spam Terrier can only monitor one inbox which for me is a deal killer.

by Anonymous on 1. May 2009 - 7:16  (20877)

I'm surprised no one has has mentioned Spamihilator
This is a very simple application sits between the email server and your client so spam almost never get into the client. It does require some training and I have added my own spam words but after a few weeks you will not get any spam in your client.
It even has an option where the spam is left on the email server and is deleted when you delete the spam.

I have tried plenty of others but I keep coming back to Spamihilator.

by Anonymous on 9. June 2009 - 8:31  (23388)

Maybe you can add Spam Fighter to the list of filters you will be reviewing?

by Anonymous on 11. June 2009 - 13:04  (23582)

Its $29 and thus... not freeware.

by peter on 11. June 2009 - 18:47  (23613)

Thank you for confirming this is not freeware.

by Anonymous on 16. June 2009 - 8:30  (23966)

Ive tried to obtain a Spam Terrier license 3 times.. is this product still valid?.. they never send a e mail license to use the product..??

by Urbane.Tiger on 20. June 2009 - 3:55  (24165)

You mention Mailwasher in the POPFile review but it gets no mention other than that

There's a freeware version of Mailwasher as well as the payware version. Free version can only handle one mail account, but it seems that it can now be a POP, Hotmail, IMAP, GMail or AOLMail account.

by Anonymous on 30. October 2009 - 16:03  (35493)

you will find mailwasher review in the spam filter for average user section

I have been using Mailwasher 2.0.28 beta for years and did not have any problem with it
It manages multiple accounts (I have 8 of them on 4 different suppliers) even web mail like yahoo, but I did not succeed in accessing my Gmail account.
Sometimes (once every 3 months or so) it suddenly freezes, I just terminate it thru task manager and restart it from my quick launch bar, and this is it, no data is lost.

It still can be found on the Internet as explained in the other section

Hope this helps!

by Anonymous on 12. January 2010 - 0:18  (40858)

Same problem. Left them a "tech support" email and never heard back. Must be junk.

by Anonymous on 12. January 2010 - 21:13  (40909)

Received an email with a registration key. Apparently their automated response does not work well. The program install OK and so far, I like what I see.

by Anonymous on 9. March 2010 - 21:42  (45264)

I was using Spamato for Thunderbird for several months and it was great; I even recommended it to my friends. Then all of a sudden it stopped loading at Thunderbird startup. I tried uninstalling and reinstalling several times with no success, and e-mailing the developer about this problem but I never got a reply. Has anyone else had this problem with it?

by Anonymous on 9. March 2010 - 21:43  (45265)

Excuse a dumb question from a newbie, but are there any free anti-spam programs that work within an e-mail client, rather than as a standalone?

by Anonymous on 20. April 2010 - 14:32  (48043)

k9 worked well for me. used with oe6, tbird 1.? (Then i think i used built-in bayesian*** on tb2 or tb3 beta. i don't recall exactly.) on Winme then Winxp. Had k9 'chained'... from yahoo mail thru proxomitron (likely unnecessary, especially since i always read plaintext mode), thru k9 to email app. :)
k9 doesn't handle imap (just checked, last ver k9 is apr2004. says also doesn't handle ssl, etc)

Tried Spamihilator (just checked 'blog': latest ver dec2008) for short while. seemed good, but also seemed bulkier than k9 and i didn't use imap, so i returned to k9. K9 has 'wizard' like button to convert OE accounts. IIRC, this function also has a backup to restore settings of those original oe accounts. I never tried the button. :)

Am now trying Komamail 1.80 with built-in bayes***, whitelist & blacklist.
Small warning: before setting up account & running, go through the settings. Most important (imo), turn off the webbeacon-allowing image setting.
I chose to setup KM as portable & it seems mostly ok so far.

*** but for obvious reasons, i prefer the spam filter app be independent of email app(s). :)

I'm interested in any bayesian app that fliters beyond just Spam vs NotSpam.

This has good info beyond tbird info

PS. Thx for this website. Has one of the most economical ratios of info:bulk on the net

by Anonymous on 20. April 2010 - 16:28  (48053)

also forgot to mention among many k9 options, can connect to one of the ~public blacklists. see screenshot of options pane, where you enter the "url" of the blacklist. Scroll down to "blackhole list, or DNS blacklist (DNSBL for short)"
another feature i never tried. i'm thinking now, i should just use k9 with the "best" multiaccount email app i can discover. I've got backups of the old white and blacklists (which are easily edited text).

by Anonymous on 14. May 2010 - 1:33  (49755)

there is a free version.

by MidnightCowboy on 14. May 2010 - 9:06  (49768)

Seems you're right!

"SPAMfighter has partnered up with Microsoft to build the strongest, safest, and most effective anti spam filter on the market. If you use Outlook, Outlook Express, Windows Mail or Thunderbird and you want to get rid of spam, just install SPAMfighter".

"And if you use it at home, it's 100% free".

by Syd Barret (not verified) on 8. August 2010 - 15:26  (55632)

Personally, I think Spamihilator is better than any anti-spam app mentioned here. It's free, it works with ANY e-mail client; not just Outlook Express. It can be used for both POP and IMAP accounts; it's been actively developed for years; it's rock solid stable; and it's available in 32 or 64 bit flavors.

For that matter, why would anyone worried about getting malware, trojans, etc. on their computer be using Outlook Express or Windows Mail as it's now called in the first place? That and Internet Destroyer are the two most exploited and dangerous apps you can use! Do yourself a favor and switch to something else now!

Nevertheless, Spamihilator combines a Bayesian filter, a spam word filter, the online DCC filter servers along with many additional plugins to use if you wish. A few plugins are installed and enabled by default including the DCC filter. Of course, you can disable any of these in the settings however I wouldn't recommend it. For example: one of them filters and blocks images hosted on remote servers which have the capability to put all kinds of nasty things on your machine.

I've used Spamihilator for years and I cannot live without it. At one time or another, I've tried all the others mentioned here along with some that aren't only to find them woefully lacking IMHO; particularly in ease of use when compared to Spamhilator. The same goes for Linxu and BSD; again IMHO there's nothing available for either that's in same league as Spamhilator with it's combined ease of use and power to stop the junk from getting into your inbox. In fact, I wish the author would port it to Linux. If not, it would be nice if a competent coder would attempt to make a clone because something very much like it is desperately needed for both Linux and BSD.

It's very easy to permanently block e-mail addresses and/or sender names with the use of wild cards. For example: when blocking an e-mail address, I always set the sender name to * and their e-mail address can be set to something like *, or sometimes the spammers will use the same email address only changing the first part of the address and you'll need to do something like this: *@* or this *@*.ru. Once you have blocked senders; you can save time and bandwidth by choosing to have all messages from blocked senders immediately deleted off your POP and/or IMAP servers without ever being downloaded to Spamihilator at all.

Configuration is automatic with Outlook 2000/XP/Express, Eudora, Mozilla, Netscape, IncrediMail, Pegasus Mail, Phoenix Mail, and Opera however manual configuration is very simple if you're using another client.

To configure it manually; you change two settings in your e-mail client's receive mail configuration section. You change your pop3 server to localhost or to and you change your user name to for example; that's it.

Basically, Spamihilator is your local mail server which sits between your POP and/or IMAP servers and your mail client. It receives the mail from your servers; checks it, then sends it on to your e-mail client. The mail that doesn't make it to your inbox goes into the "Training Area" where you check to see if any mail you actually want is in there. In the training area you mark the mail as "Spam" or "Non-Spam." In addition, you can add any e-mail addresses to your "Friends" list or to your "Blocked Senders" lists here as well. If you add any e-mail addresses to your "Friends" list; the mail from them will be automatically restored and sent to your e-mail client the next time mail is checked. You can also add addresses to either list manually in the settings.

After looking over the mail in the "Training Area" you select "Learn" and the mails are sent to another section of Spamhilator called the "Recycle Bin" where you once again have the opportunity to look over the e-mails. If a mail has somehow ended up there that you want; you mark it and select "Restore." After you're done in the "Recycle Bin" you select "Empty Bin" and the mails there, except those to be restored, are permanently deleted.

After a short period of training Spamihilator using the default setting of "Normal" and blocking a few sender names and addresses your days of getting junk in your inbox will be over. Then again... for those of you who only want to receive mails in your inbox from people in your "Friends (whitelist)"; you can always go hardcore and ratchet up the "Aggressiveness" up to "Very High" which will only allow messages from those in your 'Friends" list to get to your inbox. The rest will go to the training area for you to look over at your leisure. ;)

The configuration file is an .ini which can be edited by hand using notepad, etc. if you feel the need. ;)

It's easy enough for anyone to use however it has numerous options for the advanced user to tweak as well.

Spamihilator is very highly rated on, and many other sites as well. It has been for years now. Check it out; I don't think you'll regret it.

While all of this may sound complicated; it's not at all. Once you get used to it; you'll more than likely wonder how you ever lived without it. ;)

best regards,


by kendall.a on 8. August 2010 - 17:37  (55637)

Moderator's Note: Please keep your comments here relatively brief. If you wish to discuss topics in more detail, please go to our forums. The forums are a much better place to discuss topics in detail or in length. Thank you.

by Argo Buinevitš (not verified) on 15. July 2011 - 17:38  (75559)

Thank you, Syd, for sharing your experience!

I have used Spamihilator also for years and it has worked well. In SnapFiles the Spamihilator is till today top rated as best Anti-Spam Tool.

Of course it's not perfect. Sometimes you see some good mail in its RecycleBin and have to save them and it happens that some spam comes through (very-very seldom). But is there any antispam program, which works perfect 100%? So I looked the antispam programs, introduced here and thought that maybe there are nowadays even better programs than Spamihilator. But are there?

Actually it would be very good, if moderator of this antispam section would test Spamihilator and give evaluation comparing with other programs (pros and cons). Thank you in advance!

by Andrew96 (not verified) on 17. March 2012 - 1:58  (90724)

I completely agree with Syd's comments.

I have tried other spam filters but I keep coming back to Spamihilator. The most important feature for me is that it stands between the pop/imap servers and your email client and reduces the possibility you might accidently open a exploitative email.

The filtering options are also very powerful but it is easy to train.

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