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.

Recent Changelog:

9/14/2014-Replaced http links with https links wherever possible.

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 installation process simpler and made this advertising option more visible.


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.

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. My advice would be that if you want to install Avast you should not use the Software Updater tool.


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.
Also, note that although the download page linked to above does not list Windows XP as being supported, Windows XP x32 is fully supported, although Windows XP x64 has significant limitations.

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 searchlight on 9. October 2013 - 5:37  (111329)

If you like MSE, then stick with it. It is just a matter of opinion.

by searchlight on 9. October 2013 - 5:35  (111328)

I did read the comments, and the person to who you refer in your quote is different than the one in the quote I mentioned.

Regardless, if Microsoft Programming or Software Managers cannot get their stories straight, they both seem contradictory to me, I would rather deal with a product that is more proven and established as effective.

by MidnightCowboy on 9. October 2013 - 6:16  (111331)

IMO this is prime example of how the media are able to manipulate readers into believing something that isn't true. The quotes from Microsoft in the article you referred to are no different (of course) from the source they were copied from.

The fact remains that no one security product will protect users from everything no matter if the vendor calls it "360", "Total" or anything else that sounds like it will.

Member cybersun comments below that he has used MSE for three years without any issues, and yet was considering changing on the strength of this article. This is what these folks want you to do of course because the revenue they generate does not come from MSE but from the advertising and so called "offers" they promote for paid antivirus. This is just tabloid journalism come to tech media. Maybe the author used to work for the Sunday Sport. :D MC - Site Manager.

by Tod on 24. October 2013 - 7:56  (111718)

"The fact remains that no one security product will protect users from everything no matter if the vendor calls it "360", "Total" or anything else that sounds like it will."

I'm a little confused now. I was wondering which one would be better, Bitdefender or Avast 2014. Do you think both are so good as each other?

by MidnightCowboy on 24. October 2013 - 8:07  (111719)

Both are very different in that Avast! is a full on application whereas Bitdefender adopts a more minimalistic approach. In this respect the configuration options are limited which might not suit users wanting to have total control of their security configuration. The detection power of Bitdefender however is top notch so overall the protection performance will be very similar. Both program though will need some supplementary assistance to achieve optimum system protection. See the link below for some suggestions. MC - Site Manager.

by Tod on 24. October 2013 - 8:53  (111722)

Thanks, MC. I checked that page. Very informative! It helps me a lot.

by searchlight on 9. October 2013 - 13:45  (111335)

If you look closely at the articles, these are not examples of media manipulating readers but contradictory quotes by Microsoft's own people. That being said, Microsoft should be making one consistant statement across the board regardless of test results or efficacy debates.

If a company cannot, will, or appears not, to stand behind their security product, then I personally am not comfortable using it.

Like I intimated earlier, useage boils down to personal preference.

by cybersun on 5. October 2013 - 17:53  (111264)

Listen, I am a bit surprised to read your review. I just ended up reading an article in HOW TO GEEK where they specifically say that even MS recommends now to use 3rd party AV, as their MSE now ranks last in the list of FREE AV Software. Isn't that info available to you also? In fact all agree in saying that AVAST is the best Free AV but has a loaded interface... I would be thankful to read any comments by knowledgeable individuals on this topic. I have trusted MSE for over 3 years now, I haven't had any issues, but reports such as the one in HOW TO GEEKS (yesterday newsletter) worries me. Of course MS reputation for their blunders help in not feeling to safe about MSE or its future in fact.

by MidnightCowboy on 5. October 2013 - 23:41  (111266)

This website and others are taking what Microsoft actually "said" out of context. Most of what was "said" relates to the ability of MSE to pass tests which is what they and other vendors spent a lot of resources on previously. In yours and my real world, these tests are as irrelevant to antivirus programs as Matousec is to firewalls. You could of course keep a log of your internet and other computer activity activity, spend 6 hours a day comparing this with what your antivirus "fails" on in various tests, find one that matches and say Oh yeah, I went to this site on 19th July so maybe I was at risk. This of course is impossible and would also be a ludicrous exercise, even if it was.

What Microsoft did say was this:

"It’s not as efficient to have one kind of weapon. "Like anything you must have that diversity. It’s a weakness to just have one."

This is what we here have been saying ever since the site was set up. Multiple layers are necessary in order to provide optimum protection including browser extensions, a DNS filter and the adoption of safe surfing practices. No one single product can achieve this on it's own although many vendors claim to. This is described in more detail here:

The bottom line is, if you have been using MSE for three years and not been infected, why now should you suddenly be at risk? MC - Site Manager.

by Phylis Sophical on 2. October 2013 - 17:00  (111179)

Windows Security Essentials does not run on Win8. Windows Defender runs by default and now includes virus detection.

A good review of Defender and other Win8 protections can be found here:
However, they too state that "Microsoft has said that Defender on Windows 8 provides an 'acceptable minimum level of protection', and that it will disable itself automatically if another antivirus suite is installed"
Maybe MS is just being honest. :)

by JonathanT on 7. October 2013 - 8:33  (111291)

The main reason it'll disable itself automatically is to avoid conflicts that may arise from multiple AV's running at the same time. Worst case scenario would be system crashes and so on.

by Joe A.TT on 2. October 2013 - 19:11  (111180)

You should be careful not to confuse MICROSOFT Security Essentials with WINDOWS Security Essentials. Believe it or not, there are some questionable sites offering the latter, e.g.

Rogue antivirus programs have been known to take advantage of people who are careless about the exact name of a program.

by Phylis Sophical on 2. October 2013 - 20:57  (111182)

My Bad, Joe. Seems I can't edit that anymore to change to MS.

by mrinmoyjk on 1. October 2013 - 4:46  (111139)

"Microsoft has admitted Windows users should install antivirus above and beyond its own Security Essentials, describing its protection as merely a "baseline" that will "always be on the bottom" of antivirus software rankings."

So, how about replacing MSE with Qihoo or Comodo antivirus?

by MidnightCowboy on 1. October 2013 - 5:16  (111141)

Please supply the quote from Microsoft stating this and not the interpretation of their meaning from a media publication that obtains revenue from commercial security software. In fact no such quote exists from Microsoft and if users read the whole article they will obtain a more balanced view, including that related to tests.

This is just another example of the 'mine is better than yours' scenario whereas ever since malware first appeared no single application could guarantee to protect against 100% of it unless additional measures were taken "above and beyond" its own capabilities. Of course the vendors of commercial products continue to claim this because they want users to buy their software instead of using free solutions.

In this respect, MSE will always have a place in this review. Thousands around the world use MSE without getting infected and I still receive emails from owners of top commercial programs that have failed to do so.

In summary, PC security does not revolve around the installation of one single product and thereafter being safe. If users employ MSE as their "baseline" solution and then adopt the same measures necessary to compliment other products, then the resulting level of safety will be the same.

by mrinmoyjk on 1. October 2013 - 15:19  (111149)

I just quoted what the website said. I have no problem if Gizmo's freeware review MSE. I too have good experience with it regarding protection. Specially zero false positive. But I had some performance issues on two different computers while using it though.

by MidnightCowboy on 1. October 2013 - 15:51  (111150)

I too experienced very high intermittent CPU with one installation and was never able to effect a permanent cure. This was quite some time ago now though so maybe this is no longer an issue. MC - Site Manager.

by AJNorth on 28. September 2013 - 8:56  (111067)

Some may find the following post in the Avira Support Forum of interest:

"We’ve listened: Goodbye Notifier Ads!

Dears Customers,

The so called “Notifier” which for the Free Antivirus users pops up once a day (if you didn’t install the Avira Search Free Toolbar) to sell you something is about to disappear.

Starting with October 1st, you will never see it again.

For more information, please have a look here: ."

- - - - - - - - - - - - -

In addition, the first Beta of Avira Free A/V 2014 has been released.

by JonathanT on 30. September 2013 - 9:36  (111106)

That is excellent news!

by AJNorth on 30. September 2013 - 10:05  (111107)

I agree, JT.

Of course, it remains to be seen just how well v. 2014 will perform, so Neil Rubenking's testing & review (PC Magazine), along with those of the various A/V testing labs, are eagerly awaited. (Too bad they're apparently retaining the Ask toolbar...)

As a side note, given the recent positive reviews that Comodo Internet Security has garnered (AV-TEST; Tom's Guide), might you consider putting it in the queue for a review?



by sicknero on 30. September 2013 - 18:37  (111132)

Interesting that this announcement follows their recent relatively poor performance in AV tests. They used to be regularly in the top few but seem to have slipped lately, perhaps this is a way to offset this.

I don't use it any more though and can't say the advertising ever bothered me that much anyway.

by Chakra on 29. September 2013 - 5:34  (111075)

They should have done this a lot earlier, but I will take it. Any news on the webshield and the ask toolbar in the free version?

by AJNorth on 29. September 2013 - 8:53  (111078)

The only description of the 2014 Beta I am able to find at this time is at . Under "What’s new in Avira Free AntiVirus 2014 Beta," it describes a fix to the ask [sic] installer, so it appears that the toolbar has been retained, unfortunately (hopefully as a selectable option). They also provide a download link (the executable is 117 MB).

by Paxmilitaris on 27. September 2013 - 20:40  (111003)

With Avast, you have to be careful not to get stuck with the Internet Security.

How does rank?

by whycue on 23. September 2013 - 14:00  (110950)

My new PC came with Windows 8 - are there any recommended free antivirus/antispyware programs I can use with it?

by Anupam on 23. September 2013 - 14:14  (110951)

Any of the AVs suggested in the review will work fine. You can also read the comments to look for suggestions which are not covered in the review.

I personally use Avast, and it's working great with Windows 8.

by mrinmoyjk on 22. September 2013 - 17:46  (110923)

On their website ( ), it says Comodo Internet Security is free. I've no idea as I've never used it. It also scored well: .

by AJNorth on 28. September 2013 - 17:32  (111069)


Having used the Comodo Firewall (in various incarnations) for over a decade on several machines (with high regard), and their full suite off-and-on, my experience with the current version running on a client's Win 7 laptop (I7-3630 QM, 8 GB DDR 3) for the past four months has been quite favorable.

Comodo I.S. has enjoyed a reputation for keeping a clean system clean; its ability to remove detected malware had been somewhat low previously, but has been improving of late.

A recent overview by Tom's Guide of the various free antivirus solutions discussed above, and a few more, can be found at,review-178... . From their conclusions:

"If, in your eyes, protection against malware is more important than the defenses against phishing and Web threats, then Comodo wins with some top-notch real-time defenses."

As that well-known disclaimer goes, your mileage may vary. Best of luck.



by MidnightCowboy on 28. September 2013 - 23:40  (111073)

IMO their conclusion is a bit ambiguous considering most malware now comes from web threats. MC - Site Manager.

by AJNorth on 30. September 2013 - 10:04  (111074)

Indeed; all the more reason to employ a defense-in-depth strategy, which includes (amongst other things) using a secure browser (such as Firefox with an add-on such as NoScript) -- not to mention not doing casual browsing with administrative privileges (or much of anything else, for that matter...).

Still, the results reported by AV-TEST are impressive.

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