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 assybish on 25. January 2013 - 14:27  (104812)

Hi Wolfram
thanks - it worked and as you say just like the good old days - fast and clean. Just one problem the license runs out shortly - how cann it be extended if it is a non supported version now - I see the same question was asked on the forum link you provided ?

by Wolfram on 26. January 2013 - 8:56  (104833)

Well, I am quite sure that Avira will release a new hbedv.key file before that "expiration day". I noticed that they are doing this every six months, or so. As long as the newer versions of Avira AV will use the same old hbedv.key file, the "life" of Avira 9 will be maintained. The download link for this "vital" file will remain the same. But, I suppose you can manually update the program (its viruses definition file, I mean), even if its License has expired long time ago. I am glad that you have succeeded to set-up a fully functional machine. Try to always avoid the "Automatic Updates", if possible.-

by assybish on 21. January 2013 - 17:15  (104709)

thank you for your very helpful and well considered response.
I do have a back up system installed it is [commercial mention edited out] which whilst it is not freeware it is superb so I could get back to where I was a week or so before the Avira fiasco but of course things change in a week so I thought I could repair the system - which I did but it took some time! I could still go back to the old image but my point was the agressive way Avira behaved and how it installed and removed items without user permissions.
I did like Avira - as you say very light and pretty good detection and reasonable user control. I must say what they have done to it is needlessly agressive as well as ill thought out.
The same comments and problems apply to the paid for version if any one was thinking of trying that.
Thanks for the links to the old version and definitions updates I wasn't aware that they were available other than through automated download.
I have thought about Avast but heard some negatives abd was worried again about compatibility issues as this destroy competitors software seems to be becoming almost universal. I shall have another look given your very helpful comments.

by Chiron on 9. January 2013 - 16:57  (104355)

Please consider checking out Comodo Antivirus once more. From what I've seen it's detection rates have risen drastically and the false positives have fallen.

Also, it now includes a lot of very useful, and I believe user friendly, features.

by naren on 10. January 2013 - 6:04  (104366)

Yes, plz test & review Comodo Internet Security 6, the latest version. As Chiron mentioned the detection rates have risen drastically & the FPs have fallen, I agree. Tested it quite a few times. And I find the latest CIS 6 easy, suitable & recommended for average i.e majority of users too.

by JonathanT on 17. January 2013 - 3:14  (104554)

As MC said, I would like to wait and see for further testing by established organisations first. Basically I aim to be very conservative in the AV category, as 1. the recommendations have to fit a large target audience of average users and 2. there are already so many established AV's that work. I'm not saying Comodo AV is necessarily bad, but not as reliable as other tried and proven AV's out there.

by MidnightCowboy on 10. January 2013 - 7:35  (104371)

The editor of this category will of course make his own decisions about which products to include. It is unlikely however you will see Comodo featured until they begin to participate in more independent testing. I understand the failings of such testing (as stated by Comodo) and in the most part I agree, but even so our readers want a selection of resources to compare products with. Therefore, until we see Comodo featured on AV Comparatives, VB RAP and etc., these conditions are not met. MC - Site Manager.

by zeniorito on 24. February 2013 - 19:35  (105719)

Why include Microsoft Security Essentials then? It too failed to pass even 30% of the test samples. Microsoft should be lauded for including an antivirus product in Windows, because it seems that half the computers I repair have no working AV product. However, it requires a great deal of resources to just maintain the quality of an antivirus product, not to mention improvements. Although a good product at launch, it seems to have fallen off in detection precipitously. I have tested it myself on an extra PC I use for such a purpose, and it allowed half of the items Avira flagged right through...and then allowed execution of the viral losds. As a result, I have advised my clients to uninstall MSE and use Avira instead. I would prefer AVAST, but it confuses novices and makes even PCs with Core2 Quad processors seem like they are running on 1Ghz single-core Atom processors. AVAST does not cripple my PC, but then I have a 2500K, 12GB DDR3 and an SSD. Which is why I play safe and recommend AVIRA along with MALWAREBYTES or SUPERANTISPYWARE free versions.

by MidnightCowboy on 25. February 2013 - 1:37  (105727)

This is why.

No one amongst my own circle of MSE users has become infected over the last year and I remain confident it is an obvious and ideal choice for Windows users. MC - Site Manager.

by Anupam on 10. January 2013 - 6:30  (104367)

Is it light to run?

by naren on 10. January 2013 - 11:28  (104386)

I am running it on 3 laptops. 2 Win 7 64 & 1 XP 32. Here, light on all the 3 systems. No probs here.

Win 7 64 with 4GB RAM
XP 32 with 512MB RAM

by MidnightCowboy on 10. January 2013 - 7:30  (104370)

According to them...

"CIS 6 is the fastest and the least resource intensive product we have released so far".

Considering it was always light in general use anyway, this should appeal to a lot of folks. MC - Site Manager.

by naren on 10. January 2013 - 11:30  (104388)

Yes, here the previous versions were light too & so is the latest version.

by Anupam on 17. January 2013 - 6:47  (104557)

Thank you both. I might have given it a try on my old PC with P-III and 512MB RAM, but sadly, 256MB of RAM got bad somehow. I don't think I would run any AV on such meager amount of RAM.

by naren on 17. January 2013 - 20:49  (104594)

Is the system XP? Coz the minimum requirement RAM for CIS6 on XP 32/64 is 256MB so you could give it a try.

by Anupam on 18. January 2013 - 7:59  (104608)

Yes, it is XP. Thanks, I might give it a try later :).

by bash550 on 6. January 2013 - 10:38  (104261)

Is Avira's detection rate better than Avast's?

Apart from the nag screen, is Avira generally better at protecting your PC than Avast?

by JonathanT on 8. January 2013 - 2:29  (104311)

Avira generally scores higher than most in tests such as AV-Comparatives on-demand tests. However I honestly believe all the AV's listed in this article are equally good at protecting your PC in practical terms - if you use some common sense and good practices you will be fine with any of these AV's.

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