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 Chiron on 26. March 2014 - 16:36  (115315)

That is a strange issue. I suppose the best approach, assuming you would like to try Bitdefender again, would be to ask that question in their forums. However, if you're happy with Avira then I suppose there is likely no need.

If you have any questions about any of the other AV's listed in this review let me know.


by Arrow1234 on 25. March 2014 - 18:31  (115277)

After trying comodo antivirus for only two days, i had no choice to uninstall it before my PC had had a heart attack. While running a full scan Comodo Antivirus brought my machine to a halt, the Quad core CPU was 100% most of the time. There is no doubt the spec of the software is pretty impressive for a free product, but be aware it may take over your machine while it takes an eternity to scan your drives . I have reinstalled AVAST which i have been using for years combined with comodo firewall. The CPU hardly moves during a FULL Scan allowing you to go about your business.

by Chiron on 25. March 2014 - 23:30  (115285)

From my experience this is likely due to some sort of interference, or a problem which somehow occurred during installation. Please try reinstalling it by following the advice I give in this post:
and let me know if that solves this problem. If it doesn't let me know.

Thank you.

by sicknero on 25. March 2014 - 18:50  (115278)

I run Comodo CIS on two fairly low-end machines (single-core 2 and 2.3 CPUs) and I've not found this problem myself for several versions now. Running a scan typically fluctuates between 10 and 40% rising sometimes to about 90. Later versions have the option to run scans as a background task as well. I've not found it to be noticeably slow compared to other scanners.

by blueboxer on 25. March 2014 - 4:08  (115263)

A few months ago I tried Comodo on my XP machine, and found I had to turn off the internet connection before I could boot it. Otherwise Comodo took over the machine, and just sat there doing who knows what (my guess: a download of the whole malware signature database, followed by a full-scale scan) that monopolized my computer and did not respond to any interrupts for hours on end. Fortunately that computer has a mechanical wireless on/off switch on the front so I was able to break in and try and tweak the thing into proper behaviour, but the mitigation was slight; I eventually wiped it in disgust. My experience with avast was nearly equally bad, just enough less offensive that, faut de mieux, I elected to tolerate it for now given the oncoming demise of MSE for XP.

Obviously, I need the best fortifications available constructed around my XP facilities. Equally obviously in the past few months there have been major changes in all the anti-virus offerings and how they work. Maybe things have improved.

Clarification is needed, too. I got an "update" notification from Comodo offering added features. But a close reading suggested (the weasel=wording and misdirection is shameful) that they were trying to sell me an upgrade, likely at exorbitant subscription expense. I could be wrong - but why are they playing this game in the first place?

I just want an antivirus that works, and don't mind running a selection of separate anti-malware programs should these be necessary. I know the internet is a dangerous place and will defend as best I can. But programs that take over and run away with my computer, or try con games with me, are not things I'm eager to take on - even with your recommendation.

by Chiron on 26. March 2014 - 0:11  (115290)

Which version was this? I know that for V6 and V7 it only requires an initial update and then a quick scan. V5 used to require a full scan. Also, if the initial download takes a long time you can always manually update the definitions (directions are here)

If you are having other problems, which it sounds like you were, I would advise reinstalling by following the advice I give in this topic:

If you wish, you can try it again. If you run into any new problems, or have any questions, please feel free to contact me. I can assist you with this.

Thank you.

by George.J on 24. March 2014 - 14:55  (115257)

The only pain with Comodo Antivirus is with manual updation of definition files. After downloading the bases.cav file, ther's no easy way to update the definitions. Although I tried moving the file to /Comodo/Scanners, the program failed to detect the definitions file, and upon checking for updates again, it started downloading the whole 170MB file.

Previously using Avast, everything was quite easy. Anyway I'm still happy with Comodo IS. :D

by Chiron on 24. March 2014 - 15:20  (115258)

Instructions on how to manually update Comodo Antivirus can be found here:

Let me know if it works correctly for you.


by George.J on 25. March 2014 - 5:10  (115265)

Thanks a lot :D

But who keeps import function inside "About" :{

by Chiron on 25. March 2014 - 12:48  (115271)

Now that you mention it, that is a strange place. However, now that you found it is everything up and running correctly?

by Geert on 24. March 2014 - 11:37  (115250)

Hi Chiron,

I think there's a typo in your last sentence about the top pick:
... I do with they made the process simpler.
I suppose you mean: I do wish...

by Chiron on 24. March 2014 - 13:06  (115252)

Thanks for pointing that out. If you see any more errors please be sure to let me know.

Thanks again.

by MidnightCowboy on 24. March 2014 - 12:39  (115251)

Now corrected. Thanks Geert for pointing it out. Demonstrates admirably one of the failings of built-in spell check. MC - Site Manager

by Geert on 24. March 2014 - 14:35  (115256)

@Chiron @MC
You're welcome.
Thanks for the work you put into this site.

by naren on 23. March 2014 - 19:39  (115235)


Why do you say "the level of protection provided is not identical with the paid" in BD Free review?

by Chiron on 23. March 2014 - 20:20  (115236)

Perhaps I am wrong. Did you see somewhere where it said that the protection was identical? If so please provide a link so I can check it out.


by naren on 23. March 2014 - 21:44  (115237)

From the BD Free Manual:

What is Bitdefender Antivirus Free Edition?
Bitdefender Antivirus Free Edition is an antivirus program designed to be fast and
to minimize user interaction, while sacrificing nothing of the malware detection and
removal capabilities that Bitdefender products are generally known for.

Also a BD staff confirmed in Wilders forum. His name is Iulika0069.
He confirmed BD free provides same protection as paid. The thread is huge, its hard to find the post. There are many post by him & you will get all the info about BD free.

by Chiron on 23. March 2014 - 22:04  (115238)

I'll try to search through that later. It really is a huge thread.

However, here is an excertp from the main Bitdefender Antivirus Free Edition page here:

They say that "Bitdefender Antivirus Free Edition shares some of the revolutionary technologies that allowed our main product line to outpass major competitors such as AVG, Avast or Avira."
I'm not sure exactly which technologies the Free version does not have, but seeing as they specifically state that technologies have been removed from the Free version, I assume that the Free version also would not protect the system quite as well as the paid version.

However, when I have the time I will look through that thread and try to see if perhaps I am wrong. If you run across a relevant post before I do please direct me to it.


by naren on 23. March 2014 - 23:50  (115239)

The link you gave mentions all the features BD free has.
Active Virus Control
Intrusion Detection System
HTTP Scanning
Early Boot Scanning

The Wilders thread I mentioned, if you go through the thread, you will see BD staff confirmed on the above features too.

I think the missing stuffs in BD free compare to paid are the additional stuffs like, safepay, wallet, rescue disc, parental control, etc...

I will try to find few important info posted by BD staff on the wilders thread & let you know.

by Chiron on 24. March 2014 - 1:10  (115240)

I did notice that. What I'm not sure about are the further details. These are things such as, are signatures available just as quick to both, is the site-blocking feature updated just as frequently, is the heuristics used just as effective, is the cloud backend just as effective, etc...

Marketing often just lists that both have the same features. The issue often lies with how effective those features are for both.

Does anyone know about my above worries?


by naren on 24. March 2014 - 22:42  (115261)

If you are not sure of the details then I think you shouldn't mention "protection level is not identical with paid".

Get the details & put it in the review. The wilders thread link I mentioned in one of my previous post, you will get all the info about BD free by BD staff i.e Iulika0069.

by George.J on 25. March 2014 - 5:09  (115264)

Protection level is not just about the percentage of samples that an antivirus can identify, other features are added to a paid antivirus solution to keep you safer.

Although a home user doesn't need all those "extra's", except for large business where data security is of utmost concern.

by Chiron on 25. March 2014 - 1:02  (115262)

Thanks for pointing out the confusing wording. I have now updated it to read that "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".

If anyone can show that the level of protection is absolutely identical then I can use the results for the paid version. This can be done for Comodo Antivirus. However, until someone can show me that the free version of Bitdefender offers exactly the same level of protection, not just the same components, I cannot use those results.

I hope that makes sense.


by naren on 25. March 2014 - 17:41  (115276)

What I am trying to say is........

For example - AVG free autoupdate is not often like paid. This too can affect the protection. No Webshield/Online shield in free like paid.

For example - VB RAP test - You can see there is difference in protection by Avira free & paid. Avira free doesn't provide Webshield like paid. Avira Browser Security in free is not like Webshield in paid, there is no HTTP scanning in free like paid. Avira too doesn't autoupdate often like paid.

I know there are tests available for these AVs & that can be put in the review. But the same thing can be said about these free AVs i.e protection not identical with paid. You didn't mention this for these AVs but you mention this for BD free, that kind of looks unfair to BD free.

About BD free - I am little busy, when I will be little free, I will try to scan Wilders links & provide you the facts/confirmation about BD features/protection by BD staff. If you have time, you too try to do so.

I have tested & compared BD free with paid & other free AVs too & I find it an excellent free AV especially for average users. I find it better than all the free AVs mentioned here in terms of protection & everything for average users, not including CIS as CIS is way better than all the AVs mentioned here & recommended for advanced-intermediate users. I know my tests doesn't count, just sharing my test experience.

by Chiron on 25. March 2014 - 23:35  (115287)

The reason I did not mention that the protection offered was not the same for many of the other Free AV's is because the Free versions were tested by the testing organizations I used for this analysis. Thus, there was no need to compare the Free to the paid versions. I could just look at how the free versions compared.

However, I cannot do this for BitDefender because the Free version has not been tested by those tests. The only reason I mentioned it is because if I didn't many users may mistakenly think I could use the results for the Paid version. Thus, this is just an explanation to prevent confusion about why this particular methodology was chosen.

Also, I have no problems with Bitdefender Free. It does seem like a very good product. If I didn't think it was I would have removed it from the review altogether. It's just that I'm trying to keep this review more factual. Thus, as I have no definitive data on how it compares to the others (using the real-world tests I referenced) I cannot recommend it over them. I'm sorry if my wording suggested otherwise.

Thank you.

by naren on 26. March 2014 - 4:50  (115296)

You have mentioned in the review that it is not tested yet by any testing organization so you cannot recommend it above others. I totally agree here.

But I do think "protection level has not been shown identical with paid" is not required.

Collect facts/info about BD free & put it in the review would be better.

I am defending BD free coz..........
Before using it, I read all the posts i.e above 100 pages in the Wilders links that I have mentioned in one of my previous post so I know the facts/info about BD free. I can mention here but that would not be enough so I asked you to go through the Wilders thread & get all the facts/info.

Thats all I have to say about BD free topic.

I know you will do an excellent job maintaining this section as I know you very well from Comodo forum. I dont know if you know me but I too am at Comodo forum with the same ID i.e naren.

by Chiron on 26. March 2014 - 17:32  (115318)

In the review I mention that the only reason I even bothered to say that the protection level has not been shown to be identical with the paid is that I cannot use the results for the paid in my analysis. I think that makes sense to put that there. Without it many users would accidentally compare it with the results for the paid version.

As mentioned previously, I do believe that Bitdefender Free is a very good product. If I did not believe that I would have removed it from this review. I did that with MSE, which was previously recommended. As for putting in additional information about Bitdefender Free, please provide me with your recommendations about the type of information which could be added. This sort of information will likely be very helpful for my next re-write.

I did assume that you were the same naren from the Comodo forums, although I was not certain until you just confirmed it. I do appreciate your comments, and I also hope you are beginning to better understand my position. Comparing AV products is a very difficult task, and there is no one perfect approach.

Thank you.

by naren on 27. March 2014 - 6:24  (115335)


I gathered few posts by Bitdefender staff about Bitdefender Free AV at Wilders.
Hope you will take time & check the posts.

Bitdefender Free AV
Posts by Bitdefender staff about Bitdefender Free AV.

Posts - Pages
54, 66 - 3
147 - 6
327, 333 - 14
381 - 16
471 - 19
545 - 22
551, 564 - 23
603, 605 - 25
683 - 28
758, 773 - 31
910 - 37
942, 943, 945 - 38
993 - 40
1491 - 60
1592 - 64
1808 - 73
1886, 1888 - 76
2190 - 88
2226 - 90

by Chiron on 29. March 2014 - 18:23  (115392)

Thank you. I will update the Bitdefender information during my next rewrite.

by MidnightCowboy on 24. March 2014 - 5:39  (115245)

For me, no matter who says what about anything, the bottom line will only be evident when the free version is tested alongside the paid as with AVG in the AV-Test results. MC - Site Manager.

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