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Best Free Antivirus Software

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Antivirus software provides an essential layer of protection from viruses, trojans, worms, spyware, adware, dialers, keyloggers, and rootkits. Don't let the name antivirus confuse you. These days every good antivirus has good detection rates for all forms of malware, not just viruses. The term malware includes viruses, trojans, worms, spyware, adware, dialers, keyloggers, rootkits, and any other software which performs malicious activities on a computer.


Sadly, the amount of malware currently in circulation is so large that no antivirus could possibly detect all of it. Despite vendor's claims, no single antivirus solution can detect nearly all new malware. There are some products out there, including some in this review, which include technologies which are able to adequately protect a computer, but any product which relies mainly on detection is statistically doomed to fail at some time. Also, using more than one real-time antivirus at the same time uses much more system resources, can cause system errors, and can even reduce protection. For my advice on how to compensate for these weakness of antivirus products, to a large extent, please see my other article about How to Stay Safe While Online. Having a good antivirus product does go a large way towards adequately protecting your computer, but in this day I would highly recommend that you add additional layers to your security.


Below I have reviewed some of the most effective Free Antivirus products currently on the market. In order to make this review more unbiased, although of course my own intuition and experience does affect my judgment as well, I came up with a particular methodology for comparing these products. This methodology is described in the following section.

Methodology For Comparing Products

The main motivation behind why I came up with this particular methodology for this review is that I value system protection against real world threats above all other categories by which an antivirus is commonly judged. It does not matter to me whether an antivirus protects the user by detecting malware, blocking dangerous sites, behavioral analysis, sandboxing, or any other approach. The most important thing is that at the end of the day your system is safe from infection. Thus, that is the attitude I have taken towards reviewing these products.


Therefore, I found Antivirus testing organizations which claim to test products against situations which resemble real-world situations. I narrowed these down by further requiring that the organizations have a relatively long record of producing good, seemingly unbiased, results. The organizations I ended up with, and therefore used for this review, are:



Dennis Technology Labs

From here I looked at all tests ranging to the beginning of 2013. However, if there were more than three tests within that range I used only the most recent three. Also, if given the choice between results from different operating systems, I chose that for the most popular operating system. At the moment Windows 7 is the most popular operating system.

Also, I only considered results if it was specifically the Free Version which was tested. This is because the results for the Paid Version of the products in this review, with the exception of Comodo Antivirus, are often quite different from those for the Free versions.

In addition, I did not count it against any of the products if they were not tested by multiple organizations. As long as they were tested by at least one, within the above-mentioned period, they were considered. This criteria was chosen because there are many reasons to choose not to participate in a test. Thus, it should not be held against the product if they were not tested by multiple agencies. However, if they were not tested by any, this makes it impossible to compare them in an unbiased fashion.


Once this data was collected, I then looked at the overall results for the Free Antivirus products discussed in this review, and ordered them mainly according to the quantitative results. However, my own knowledge of the products, and the reviews and experiences of others, were also considered. The results are presented and discussed below.

Discussion And Comparison

Comodo Antivirus is my top pick for advanced users or for Intermediate users who are okay with an antivirus software which will occasionally ask them for input. However, if you do not fall into those categories, or for any other reason find it to not be a good fit for you, then you will likely find my next pick suitable. Also, for those who prefer a complete solution, there is always Comodo Internet Security, which is also free and includes a firewall in addition to all other components which already come with Comodo Antivirus.

The reason I made this my top pick for advanced users or users who are okay with a somewhat talkative antivirus software, is because it is the only product which I feel confident saying that it will protect you against nearly 100% of real-world threats. I have a lot of experience with this product. I am a volunteer moderator on the Comodo forums and have been using it for a long time. I know this product very well, and am entirely confident in its ability to protect.

Comodo Antivirus uses the cloud to facilitate the detection of the most recent malware, as do many other Free Antiviruses reviewed in this article. However, Comodo also incorporates a Behavioral Blocker, which will automatically sandbox all software which it does not know for sure is safe. Thus, the user is protected from nearly all malware, which will either be detected by the antivirus component or sandboxed by the Behavioral Blocker. It will also analyze unknown applications for suspicious behavior, and alert the user accordingly.

However, as mentioned previously, users who do not want a somewhat talkative antivirus should continue to my next pick. Also, by default Comodo Antivirus has small advertisements (which can be disabled as shown here). Also, during installation users should be sure to click the Customize Installer option, which is near the bottom-left of the installation window. This will allow them to uncheck additional software, which the installer will automatically install with Comodo Antivirus unless unchecked. This software is not dangerous and includes a browser, and ad-blocking addon, and an optional paid service which would allow Comodo technicians to assist you with any computer problems you have. These, and a later option to change your homepage to support Comodo, can safely be unchecked during installation. Even with this extra hassle, this software is still my top pick, but I do wish they made the process simpler.


Avast! Free AntivirusAvast! Free Antivirus is has very good protection rates. Avast has many different protection shields, boot-time scanning, a behavioral blocker, an internet site ratings plugin, script malware protection, and access to cloud-based protection. It's arguable whether their ratings plugin offers comparable levels to WOT, but the script malware protection can prevent certain browser exploits, a feature not available in any of the other free AV's reviewed.

Avast is also relatively light on resources. However, do note that Avast requires a free registration to function after 30 days, and the default installation installs the Chrome browser unless you uncheck it. Also, note that the OpenCandy advertising component is integrated into the Software Updater tool in Avast. More information about OpenCandy can be read here. Thus, if a user selects this option during the install they will end up with OpenCandy on their computer. Please be very careful about this option if you choose to install 


Panda Cloud AntivirusPanda Cloud Antivirus is another excellent choice for average users, who may find both Comodo Antivirus and Avast too confusing. It has a simple interface, completely automated features, access to cloud-based protection, and has been shown to be very good at protecting a computer. Panda Cloud Antivirus has a behavioral blocker, web protection, and access to cloud-based protection, all of which will help increase your security.


AVG Anti-Virus Free EditionAVG Anti-Virus Free Edition is also a decent choice for average users. My analysis of the results, as discussed in the methodology section, does show that it does a decent job of protecting your computer. However, it appears that the above Antivirus products tend to do better. Also, it comes with advertisements (but they can be disabled).


Avira AntiVir Personal EditionAvira AntiVir Personal Edition is another product which has a very good reputation. However, the free version was not tested by any of the three testing organizations I referenced in my methodology. Therefore, I cannot currently recommend it above any of the previously mentioned products.

However, other comparative tests do show that it has very high detection rates for malware. Also, many users have used it and found that it is very effective. Also, users have access to cloud-based protection. AntiVir is certainly a good choice for a free antivirus, but due to the lack of real-world testing, at this time I cannot recommend it above the other products in this review. Hopefully in the future they will have the free version tested by these organizations as well.


Bitdefender Antivirus Free Edition

Bitdefender Antivirus Free Edition is another free antivirus product which has a very good reputation. However, the free version was not tested by any of the three testing organizations I referenced in my methodology. Therefore, I cannot recommend it above any of the previously mentioned products.

The engine for this product appears to be the same as for the commercial product. However, the level of protection provided has not been shown identical with the paid version, which is why I did not use the results for the paid version in my analysis. The user interface for this product is very minimalist. Thus, it may be attractive for novice users, though more advanced users may be frustrated at the lack of customization. Bitdefender Antivirus Free Edition is a good choice for a free antivirus, but due to the lack of real-world testing, at this time I cannot recommend it above the other products in this review. Hopefully in the future they will have the free version tested by these organizations as well.


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Quick Selection Guide

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

Runs as a stand-alone program on a user's computer
This has full real-time protection capability, including real-time antivirus, behavioral blocking features, cloud-based protection, and an automatic sandboxing function which protects users from nearly all malware.
The automatic sandboxing function, although not very intrusive, may be too talkative for some users. Also, by default non-intrusive advertising is enabled (although it can easily be turned off).
Version 6.x
32 and 64 bit versions available
Unrestricted freeware
There is no portable version of this product available.
Windows XP, Windows Vista, Windows 7, Windows 8.x

Take care to avoid the installation of unwanted software during installation. To do this use the customized installer button, which is on the lower left-corner of the screen during installation. Additional software, including a browser, an ad-blocking addon, and an option paid service which would allow Comodo technicians to help you with computer problems, are all included by default.

Avast! Free Antivirus
Runs as a stand-alone program on a user's computer
This has full real-time capabilities, behavioral blocking features, script malware protection, and a low rate of false positives.
Default settings require certain user interaction. It is bundled with Chrome browser by default, and if not carefully avoided during installation the user may accidentally install OpenCandy (see discussion for clarification).
Version 9.x
32 bit but 64 bit compatible
Feature limited freeware
There is no portable version of this product available.
Windows 2000, Windows XP, Windows Vista, Windows 7, Windows 8.x, Mac OS

Take care to avoid the default inclusion of the Chrome browser and OpenCandy during the install process by using the custom install option. The attempt to install these will also be repeated at the program update if the automatic option is chosen.
Quick Start Guide:

Panda Cloud Antivirus
Combines a web service with a stand-alone program
High detection rate of malware, web protection, some behavioural blocker features
Detection rates of real-world malware is slightly lower
Version 2.x
32 and 64 bit versions available
Free for private use only
There is no portable version of this product available.
Windows XP, Windows Vista, Windows 7, Windows 8.x
AVG Anti-Virus Free
Runs as a stand-alone program on a user's computer
Behavioural blocker
Slightly lower signature detection rates
Version 2013.x
32 and 64 bit versions available
Free for private use only
There is no portable version of this product available.
Windows 2000, Windows XP, Windows Vista, Windows 7, Windows 8.x

Forum for support

Avira AntiVir Personal Edition
Runs as a stand-alone program on a user's computer
Outstanding detection of malware
Not the most user friendly
Version 14.x
32 bit but 64 bit compatible
Free for private use only
There is no portable version of this product available.
Windows 2000, Windows XP, Windows Vista, Windows 7, Windows 8.x
Bitdefender Antivirus Free Edition
Runs as a stand-alone program on a user's computer
High detection rates, very user friendly
Lack of customization
Version 1.x
32 bit but 64 bit compatible
Free for private or educational use only
There is no portable version of this product available.
Windows 2000, Windows XP, Windows Vista, Windows 7, Windows 8.x


This software category is maintained by volunteer editor Chiron. Registered members can contact the editor with any comments or questions they might have by clicking here.


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by Anonymous on 11. January 2009 - 23:42  (13661)

OK then, how about this for chucking some petrol onto the fire. Some time back I worked out (roughly - I'm not completely sick!) what percentage of my PC usage time was spent mothering my tribal collection of security applications.
Then I added into that the "worry factor" associated with my surfing habbits. Most of you will identify with that "feeling" you get when something doesn't go just right and you wonder what will happen during the next boot! In summary I chucked out Windows and installed Linux. Would have liked OpenSUSE but opted in the end for Ubuntu as being a more friendly transition. Whatever malware does exist for linux will invariably need root priviliges to run and the forums advise that anti-virus's are just not necessary. I run a GUI just to give a graphical interface to the pre-installed IP tables (firewall) and that's it. No worries - and much more time spent surfing! Just a thought.

by Anonymous on 12. January 2009 - 10:13  (13702)

I'm also thinking of throwing Windows away and installing Ubuntu.
The problem is that Linux does NOT offer a user
the variety of programs Windows do.
In terms of security, Linux is, by far, more secure.

by Anonymous on 13. January 2009 - 12:31  (13807)

I need to know if any of the Non-Portable ones have a seperate database update...Cause I update on i-cafe's due to dial-up...

by Anonymous on 13. January 2009 - 12:31  (13808)

Me Again, my email is

I really need to know...

by Anonymous on 13. January 2009 - 12:56  (13810)

I know that Antivir Avira does

by Anonymous on 13. January 2009 - 15:37  (13819)

Potential users of Avast may be comforted to know that there are several very good skins which can replace the (admittedly confusing)default interface. The "MacLover's" interface in particular is an excellent and well laid-out skin that would offer little to confuse the average user. All are available for free download on the Avast home site.


by Anonymous on 13. January 2009 - 21:35  (13842)

For an "On Demand" scanner I suggest "online" scans. They are all free. One week scan with Norton, NOD32 the next, Bit Defender and then ? In the course of a month you will have scanned with 5 or 6 of the best. I don't think anyone is good enough to hid from their combined searches.

by Anonymous on 17. January 2009 - 12:41  (14081)

avast! Home Edition 4.8 has the same detection rates as pro, just pro has some more features, is faster at on-demand scanning, and uses less RAM and doesn't use as much processing usage

by compgenius999 on 17. January 2009 - 13:13  (14083)

If you want protection, you should get Avast! Home Edition, it is free and offers protection that even most paid anti-viruses don't give you it, such as a web shield to block the viruses from even reaching your computer, i've only seen something like that in KIS 2009, but avast is better than that, it includes IM and P2P protection, so you don't get infected in the first place, and a boot time scanner, i don't think ANY anti-virus has ever included that, only avast, so if you want free protection, then just get avast, its free and hasn't missed any viruses on my computer yet, and to anybody who hates the interface of avast: you NEVER need to open the interface, only time you need to open it is to activate it, and if the real-time protection was disabled for some reason. avast's real-time protection can already handle most viruses/spyware/adware/malware

by Phobos on 18. January 2009 - 1:20  (14122)

It's a bit funny reading through these posts, but it's actually quite a bit more annoying. Computer security is very important, but all I see here is "I think", "Personally I believe", "I recommend", "It sucks", and every other opinion that may or may not mean anything to anybody. What I don't see is any evidence to back up any of these claims. Today all that ends and you will have something new to argue about.
Here it is, actual independent testing of AV software:
Also on that site are links to other independent software testing sites:
After reading some of the PDF docs on how testing is conducted, let me say this. "I personally believe that the info doesn't suck and I highly recommend studying the independent testing process. After evaluating the process and forming your own opinion, I personally believe and recommend that we should all meet here tomorrow and argue about how wrong everybody is." But that's just my opinion.

by Anonymous on 18. January 2009 - 9:42  (14136)

I've looked at those, but they just can't compare to real world experience. Everyone seem s to have an option I know, some opinions are better than others.

There are two major things to look for in an Antivirus, First is detection rates, and the other is scanning speed. Now everyone seems very familiar with the first, but not as familiar with the second. Scanning speed, and how your antivirus affects your system performance is very important. Take a system with a clean windows install on it, and no antivirus, and it will fly. You'll be amazed at the difference in the performance and snapyness of the system. Then you put antivirus on it, and the system slows down. Why, because everything you do is getting scanned for viruses. Everything now has to go through that scanner. If that scanner is slow then your system is going to be slow.

Now the problem that I have with the tests that you linked to is that it says that several antivirus that I know have slow scanning speeds have fast scanning speeds. Even the reviews here contradict these tests. The test says that AVG has fast scanning speeds, but here its says AVG "has very slow scan speeds".

I have used avast for years. I use it on all the computers that I work on. All the computers that my family all use avast. Its not perfect, but it the best FREE solution that I know of.

by giantjoebot on 18. January 2009 - 9:48  (14137)

Along with some other people on here I would like to know how Comodo stacks up to the rest.

by Anonymous on 18. January 2009 - 10:30  (14142)

100% Agree!!!

Moreover, AVIRA AntiVir Personal

has NOT protection against Spyware and Adware as shown at:

by Anonymous on 18. January 2009 - 10:45  (14144) seems to be independent in the first place.
However,they some obsession with ESET Nod32.

Look at the Summary Report 2008.
Although AVIRA AntiVir PREMIUM Edition
was the Top AV for the Year 2008,
they kept promoting ESET Nod32.

However, ESET Nod32 version 3
proved one of the worst AVs during 2008!

ESET Nod32 version 3 presented a major weakness in
Detecting and Removing Spyware!

Although ESET Nod32 version 2.7 was a legendary AV,
ESET Nod32 version 3 has a failure!

Throughout entire 2008 comparatives,
treated ESET Nod32 nicely when the product kept going from
bad to worse!

Anyway, I believe that is, by far, a reliable AV Tester!!!
Better than!!!

by Anonymous on 18. January 2009 - 11:49  (14150)

top firewall,better than most, but popups will drive you mad.davy

by JonathanT on 18. January 2009 - 12:54  (14154)

Comodo AV was tested by AV-Test in the latest German PC Games Hardware magazine (01/2009) and apparently scored 25-30% in total, it finished last, way behind ClamWin.

However, a new CIS beta is out which includes heuristics, and according to Comodo, they have tested it and it detects 99% of what AntiVir and Kaspersky detects.

by Phobos on 18. January 2009 - 15:02  (14159)

It looks to me like the independent testing pretty much verifies the list recommended here, but it is that 1 virus that gets through that can make your day go bad. The best thing I ever did was to buy Acronis True Image and run a backup everyday. My comp is so old that I just cant run full time AV plus Crapware detection and Acronis has saved me from a few Crapware incidents lately. It's just a home comp, so if I lose a day it's not a big deal. Acronis also has a Try and Decide Service (Virtual Mode) that works excellent at the cost of only 4mb of ram. If this were a work comp, I would go ahead and pay for NOD32 also.

by Anonymous on 19. January 2009 - 3:06  (14175)

Any body knows something about PC TOOLS AV ?

by JonathanT on 19. January 2009 - 4:09  (14181)

It uses the VirusBuster engine with some enhancements. VirusBuster isn't that great in detection though.

by JonathanT on 19. January 2009 - 9:34  (14188)

Thanks for the information, it's appreciated.

by Anonymous on 19. January 2009 - 10:34  (14189)

kept freezing computer,could not even move mouse to log off.pity looks good.davy

by Anonymous on 19. January 2009 - 16:16  (14216)

You're exactly right----evidence is imperative in making informed decisions---I agree with you 100% on this.

However, you have to 'compare apples with apples' here; your weblink to is great---but it compares PAID versions of the antivirus programs. I was not able to locate the link for evidence-based comparison of the FREE versions of antivirus programs. One cannot expect the FREE versions of the programs to measure up to the PAID versions---that's why they are FREE.

Please provide the link (or a similar one) that provides legitimate testing of the FREE programs and then your argument will 'hold water.'

by Anonymous on 19. January 2009 - 18:18  (14226)

I used PC Tools AV for over a year with excellent results as far as reliability was concerned. It had only manual updates, but they were incremental so times to download were short. I don't know much about its actual abilities as it never flagged a piece of malware or virus in the whole time I used it (to be fair, SuperAntiSpyware only flagged one or two pieces in that time). I used it (it has an "Intelliguard" to block malware from installing) along with Spyware Terminator and the Avorax Shield, so perhaps there was nothing to find.

There's precious little info in PCTools AV, and I eventually went with Avast because I at least knew its track record from various sites on the web.

Hope it helps!

by Anonymous on 19. January 2009 - 18:27  (14228)

One thing I'll add regarding my post on PCTools AV is that their support forum seems to take forever to register you should you wish to post on an issue. I registered on two different occasions months back and STILL never received permission to post. Since I switched to Avast, it was really no issue, but I thought I'd mention it for potential PCTools users.

by JonathanT on 20. January 2009 - 0:15  (14243)

AV-Comparatives doesn't usually test free products. But the detection rates that AV-Comparatives show for the paid versions is very similar to the free versions anyway, because AV-Comparatives does not test the products against spyware.

by Anonymous on 21. January 2009 - 20:55  (14343)

Avast seems to be fast; but it hinders my system performance.

For example, when I install a program, my system can't access the file, and ask me if I want to retry. Retry, Retry, Retry, ect.

This never happened before I put Avast om my system. It seems to hinder or slow down access to files. Causing my system to act funky.

It is not just my computer. My neighbor has it on his computer and it acts the same way his computer too.

I am seriously looking for a different free anti-virus to put on my system.

I might even go back to Avira AntiVir.

Cole Manager: You have 65 minutes to take the FCC GROL test.
Student: May I have a lifeline please.

by J_L on 25. January 2009 - 8:03  (14653)
by Anonymous on 26. January 2009 - 3:21  (14696)

Does anybody have any idea when comodo will submit its AV for testing.

by Anonymous on 27. January 2009 - 4:19  (14760)

Probably when they are confident that they will do well. They are not yet confident in their AV product. If you look through their forums they even say that you should use other well rated products to compliment their AV as it is not yet up to standards. Hopefully after this 3.8 beta. Hope that helps.

by Anonymous on 27. January 2009 - 22:30  (14826)

thank you and one last question when will 3.8 beta be out