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 Anupam on 16. November 2008 - 8:03  (10558)

I am using Avast, and i am quite happy with it. Saved me many times, and i didnt had any problems. If its giving a false positive, its on you to take care while deleting the particular file. Avast is one of the best out there.

I had Norton for many years, but it didnt prevent me. Same for NOD32. Both let the virus creep in the PC. I used AVG and Avira for sometime, both worked nice for me. AVG 8 is not so good... Avira has some update issues. Avast is working nicely for me.

Anupam Shriwatri, India

by Anonymous on 16. November 2008 - 14:08  (10563)

I also use Comodo, maybe ST real-time protection is conflicting with Antivir.

by Anonymous on 16. November 2008 - 14:45  (10566)

I think that Avira is the best one cos of its detection rate, it now seems to me that a lot of the paid antiviruses aren't as good as Avira for detecting viruses and such, what with the 98% detection rate, the only bad things about avira is that its really good for detecting and stopping viruses, but doesn't have many features, i don't really like AVG any more, because i installed it on three computers, and on all three is detected like 40000 files to be bad, and all three computers were perfectly healthy, so i think they were all false positives. Avast is alright, but its detection rate is something like 88%, so its a good all-rounder, but i prefer Avira for an antivirus. Id get the premium to support Avira, but my parents don't want to pay for antivirus (yeah, im only a teenager).

by Anonymous on 16. November 2008 - 18:09  (10573)

uninstalled then reinstalled avira. now umbrella opens at start.

by Anonymous on 17. November 2008 - 1:12  (10580)

Nothing personal but did you know that you have to manually update Avast versions one at a time. The stupid thing continues to gather AV signatures but what good is that if you forget or don't know to update the "program" versions manually. Avast sends no warnings as to new program updates either, another fopah. The user interfaces are stupid and there are about 6 of those to confuse most users as to how to just scan the whole computer. The desktop icon is also different than the toolbar icon taking the user to yet another portion of this stupid program. The "car player interface" sucks too as I can't figure out what it even does. It seems to do nothing at all. Whoever designed this piece of crapware gets an A+ from me for genius or idiot required to operate it successfully. As the guy above mentioned this software has one of the highest false positive ratings of all the AV's on the planet. No wonder that guy allowed Avast to delete and damage his safe program files. It's as the guy above who's computer got wiped out said it's an expensive venture into the tech shop. I'll stick with Avira and the latent server problems for now.

by Anonymous on 17. November 2008 - 5:30  (10590)

Get Comodo or Online Armor along with DriveSentry and Avira. All free for the take.

by Anupam on 17. November 2008 - 7:52  (10597)

Avast does tell you, when a new version is available. And you can update it online too. I have done it myself. About the interface, it depends on person to person. I also didnt like the interface first. But once u get used to it, its okay. Avast is great, and one of the best. Its certainly not crapware, as its saving many people's PCs out there.

Anupam Shriwatri, India

by Anonymous on 18. November 2008 - 17:49  (10678)

Why not buy Avira Premium / Security Suite ?

by Anonymous on 18. November 2008 - 18:24  (10682)

McAfee Big Big Mistake If you do want to buy go Avira Premium or Avira security Suite


by Anonymous on 19. November 2008 - 2:16  (10718)

How the hell can AVG & Avast be better than Avira ?

by Keyur on 19. November 2008 - 4:41  (10722)

The only reason why AVG and Avast are mentioned ahead of Avira is they are more complete as compared to free Avira doesn't include spyware protection and Email protection.. As far as detection rate is concerned Avira is still 1st choice..

by Anonymous on 20. November 2008 - 19:31  (10775)

Is it possible to install AVG so it only checks email and spyware?

by Anonymous on 22. November 2008 - 18:59  (10857)

I have a subtle point about the Avast review above -- it implies that Avira doesn't have an anti-rootkit scan. But Avira does scan for rootkits.

by JonathanT on 23. November 2008 - 3:27  (10869)

The part about AntiVir says "the detection rate of viruses and rootkits is outstanding".

by Anonymous on 23. November 2008 - 12:57  (10887)

Have just had problems with the latest Avast program online update. At the end of installation it asks for reboot, all ok.
After reboot windows gets past the "loading your personal settings" screen and desktop comes up with no icons, toolbars or Taskbar at all! Just the background, even ctrl alt del does not open task manager! or enable shutdown.
The only solution I've found is to switch off power, reboot in safe mode, and uninstall Avast.
Reboot then works and all is hunky dory again but with no antivirus.
This is repeatable and I have tried it with two different XP Pro SP3 installations and my main XP Pro SP3 installation twice with the same results.
Let us know if anyone else has this problem.

by Anonymous on 24. November 2008 - 15:33  (10930)

But the review for Avast says: "Avast is the least restricted product out of the three, with anti-rootkit and anti-spyware capabilities." So this contradicts the AntiVir review, if one of the three includes AntiVir.

by Anonymous on 24. November 2008 - 20:29  (10943)

Hey everyone. There is something fairly new on the market of free security. Or at least I think it is fairly new. Anyway, it's CIS (Comodo Internet Security). Now first off before I get flamed for saying Comodo, I am aware of the medeocre AV tests with Comodo AV, but since this is internet security it seems to have more levels of protection which may fill in the gap of the AV protection. Anyway, CIS is completly free and it comes with Comodo Firewall which is undeniably one of the best firewall's on the market, it comes with the AV and it also comes with something called Defence+. Now it seems that the Defence+ works like a rather sophisticated HIPS type program, but it also seems like a bit more then that. Within Defence+ there are protected registries and with that you can also add more for those that are computer savy enough to know what to protect, however, there is a list of the main windows core registries in there by default plus internet explorer registries which adds a bit more security for IE for those that like to surf with it. Plus another extrememly handy feature within Defence+ is "View Active Process List" which acts like the processes tab in the windows task manager, but gives alot more information about each program running and the vendor that makes the program. In that you can, if you have something malicious/dubious or that you just don't want running ie. googleupdate.exe dell/hp startup updating processes ect. you can terminate that process or if you are so enclined you can choose to terminate and block the applicaion, so that it will not start up again.
Anyway, I have been using this application for about 2 weeks now (I know fairly short time, but generally enough to get a feeling for something) and I have had no issues or troubles with it other then when I had to reinstall it right after my first install because the AV didn't show up with the install in the first place, I think it is because of some left over stuff from the original CAV's I tried about 6 months ago. Other then that, the updates have been great (which is something I care about alot) the scanner has been very good and quick (about 2.5 hours for my full scan 1-200 gig hard drive 75% full and 1-250 gig hard drive also about 75% full. about 600000 files or so. Plus if you so choose you can install the suite without the AV and run which ever you choose to. Oh, and this is also light on resources running at between 1000 and 2000 K of mem generally and eats up no processor, but the scan is higher and seems to fluctuate a bit, but is fast none the less. Anyway, can you give it a review? I just wanted to let everyone know about it.
Thanks gotta run.


by Anonymous on 25. November 2008 - 5:09  (10955)

I've been trying to say there are issues with Avast upwards of 5 months ago and no one has had an ear until now?

When I hosted this category there was no debate, and there still is no debate that Avast is a second, and even perhaps a third rate AV product. It's free, so please feel free to fight all you want amongst yourselves as to its quality in the face of other's enjoyment, including mine.

"When you test, test for real, with quality and quantity methodologies results and outcomes in mind otherwise your not a scientist, your just a reporter, and no one will listen to or care about what you say."

Jeffrey Brown
IT Security Specialist

"If you're not the lead dog, the view never changes."

by Anonymous on 25. November 2008 - 5:19  (10957)

Actually it does not. Avast's default is not set to program update, further when program update is selected it still does not tell you a new update is available. Crapware to be sure.

by Anonymous on 25. November 2008 - 5:21  (10958)

I'd like to know how to enable their stupid servers to get updates without pay.

by Anonymous on 25. November 2008 - 5:24  (10959)

Just like the Titanic, Comodo Internet Security has it all. Happy sailing.

by Anonymous on 25. November 2008 - 5:32  (10961)

Oh, I see you revised that to say Avira. Your correct. Neither AVG or Avast surpass Avira heuristic and detection rates and Avast is flawed in many other ways I won't go into here.

Jeffrey Brown
IT Security Specialist

by Anonymous on 25. November 2008 - 5:39  (10962)

They are?

Then explain this being ahead of the other two?

"Avast! 4 Home Edition is my top pick."

Avira is as complete as free protection gets.

by JonathanT on 25. November 2008 - 6:00  (10964)

Hi Jeffrey

I'm interested to hear your view on this. What issues does Avast have? How is Avast a second/third rate AV product?


by JonathanT on 25. November 2008 - 6:03  (10965)

Avira is missing antispyware protection, and AVG is missing some anti-rootkit protection, so I made that statement. I'll edit it to hopefully make it more clear.


by Anupam on 25. November 2008 - 6:32  (10969)

Well, it told me and still does. I dont know, why you are not getting it.

Anupam Shriwatri, India

by peter on 25. November 2008 - 7:24  (10970)

Nice to hear from you, Jeffrey. Please contribute whenever you can.

by fat_man74 on 25. November 2008 - 8:39  (10972)

Hello all,

I'm fairly computer & protection illiterate...basically when it comes to the ins and outs of things, especially determing what is good and what isn't. My problem with chosing the best protection possible for my Dell Latitude D610 LapTop computrer is already exacerbated by the fact it is indeed infected...I just don't know by what and how bad?? I do know however, that no software is best for all systems, and the ZoneAlarm Suite that was guarding my computer graded worse than the Lakers defensive perfomance against the Celtics in the finals (Laker fan here)! My system information is as follows:

OS Name Microsoft Windows XP Professional SP3
Processor x86 Family 6 Model 13 Stepping 8 GenuineIntel ~1596 Mhz
BIOS Version/Date Dell Inc. A03, 3/2/2005
Boot Device \Device\HarddiskVolume1
Total Physical Memory 512.00 MB
Available Physical Memory 159.73 MB
Total Virtual Memory 2.00 GB
Available Virtual Memory 1.96 GB
Page File Space 1.20 GB

I am currently running the following free protgection software:
Avira free, SAS free, MBAM free, Comodo FW w/HIPS, BOClean, SpywareBlaster, SiteAdvisor, HiJackThis, MRU-Blaster, EULAnalyzer, TCPOptimzer, CCleaner, and Comodo Registry Cleaner.

I unfortunately am still running Java and Adobe as well as other soft/hardware that came with the device. I'm inquiring of those in the know to help me equip the device with the best protection possible for it's system...I'm willing to do whatever it takes...I read all the marvelous and expert info provided by the site, and while I'm a quick study, it is a bit much to digest in one I beg of you--show me love!

Thanx a million for your time, effort and consideration...
Thomas H.

by Anonymous on 25. November 2008 - 10:14  (10980)

hi davy from scotland here,are you sure you are infected,if your computer is slowing down it maybe your running out of ram.i suggest you need at least 1gb to run xp and 2gb to run vista.running a security suite like zonealarm will eat up quite a bit of your ram (use taskmanager to find this out)even so zone alarm should deal with any can try the freebies suggested on this site,i use avira and zone alarm free,the rest of your software is fine.try a ram upgrade as ram is so cheap nowadays.

by Anonymous on 25. November 2008 - 20:00  (11010)

what format is going to be used?

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