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.


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. Bundled with Chrome browser by default (see notes).
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 Chrome browser during the install process by using the custom install option. The attempt to install Chrome 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 9. February 2014 - 0:43  (114329)

That's a very strange issue. I hope it's already been reported as a bug on Bitdefender's forum and will be fixed in subsequent updates. That said, I'm glad to hear of the workaround, and will let others know if I hear of anyone running into the same problem.


by cpuking on 12. February 2014 - 19:30  (114433)


The conflict between Bitdefender Free Edition and Ccleaner, has not been fixed. I am still having the problem. From what I understand, Bitdefender has no plans to resolve the issue.They say that it would put the computers that their product is protecting at risk, to resolve the problem. I was told by Bitdefender to do the work around, of turning off the Virus Shield, when cleaning with Ccleaner, or to delete one or the other. Bitdefender is a little arrogant, when it comes to their product. I don't blame them for that. I think they have a very strong product. So if they think that resolving the problem would put my computer at risk, then I have to agree with them to not resolve the issue. Both Bitdefender and Ccleaner are great products to have on your computer. So I have chosen to do the work around.

by Chiron on 13. February 2014 - 2:01  (114439)

Thank you for updating us about this. I'm really not an expert in how products are coded and thus will not argue with them about this. However, it does seem strange that other products do not have the same issues.

Either way, I suppose it's a relatively minor issue for a good free AV. Also, for anyone else reading this, if the issue is bothering you too much you can also switch to one of the other great AV's in this article.

Thanks again.

by TomeWyrm on 23. January 2014 - 21:58  (113945)

I've noticed a few issues with Avast lately that have caused me to jump ship back to Avira (whose major downside of annoying nag screens I can mitigate).

Issue number 1 has something to do with startup protection. Basically I can't mess with my startup entries with any of my centralized tools, like CCleaner.

Issue number 2: It recently had an annoying false-positive with my VoIP client ( RaidCall ), and then proceeded to not let me whitelist the program without going on the internet, doing research, and changing the settings on ENTIRELY too many things, instead of simply letting me say "Your last detection was a false positive".

The first one I was willing to work around until Avast updated to fix the issue, which might have taken many months (not that big of a deal. I check my startup entries once or twice a month). The second one cuts me off from effective performance in my cooperative games (group coordination is much more difficult without VoIP). That I'm not putting up with for even a week, because it's an implementation flaw as far as I'm concerned. False positives happen, and without a simple/easy way to unblock/undo those, this program is a loaded handgun being waved around by someone that isn't quite stable. What happens if it gets a false-positive on Windows Explorer next (probably signature/hash based whitelist for important OS files... but still, I'm not dealing with it), or maybe my browsers get targeted?

by Chiron on 31. January 2014 - 17:23  (114107)

Both Avast and Avira are very good choices. As for the startup protection, I was not aware of that, but I suppose the upside is that malware likely couldn't mess with the startup entries easily either. However, for a user desiring granular control I understand the issue.

As for the false positive issue, all AV's will sometimes have false positives. Sadly, with the vast amount of malware out there this sort of aggressive signature is necessary. Thus, please report false positives using the information I have gathered in my other article here:
All AV's have had false positives in the past, sometimes with important files. This is sadly unavoidable. However, the AV companies themselves are also aware of this problem, and are constantly doing everything they can do to try and ensure that the important files are whitelisted, and will thus be excluded from detection.

Thank you.

by AJNorth on 22. January 2014 - 2:06  (113854)

Larry Seltzer of ZDNET has an article some may find useful, "Antivirus on Windows 8/8.1 compared" - (2014.01.21), which references the new test results from AV-Test (

Though mostly discussing paid applications, a few consumer freeware are mentioned (and yes, Microsoft Windows Defender 4.3 was dead last).

by Chiron on 22. January 2014 - 15:21  (113883)

Thank you very much for this link. I will take a look at this when revising the advice in this article. Also, AV-Test is one of the testing companies whose results I will be drawing on to compare the products.


by AJNorth on 16. March 2014 - 8:53  (115047)

My pleasure, Chiron, and welcome aboard!


by Chiron on 21. March 2014 - 2:19  (115165)

Thank you. I am new to this article. However, I am not new to techsupportalert. I have published 13 other security and privacy articles on this website. In case you are interested in checking these out, they have been added to the bookmarks of my profile.

Thank you.

by Chiron on 21. January 2014 - 4:13  (113799)

Hello, my name is Chiron and I am the new editor for this article. I have just made a small change to the article (removing MSE due to very bad protection results). However, many more changes are coming once I have improved upon the new procedure I have come up with for comparing antivirus products. My aim is to differentiate between those products which just have good detection scores versus those which may have lower detection scores, but due to other technology can actually protect you better.

Keep an eye on this article over the next few weeks for these improvements.


by naren on 18. January 2014 - 21:06  (113707)

Currently running Bitdefender free antivirus. BD website mentions it shares the same protection technologies as their paid products.

Tested it & seems it provides the same protection as their paid products.
Tested offline too & find offline protection is also good, active virus control their behavior blocker also detected threats offline too. Its a cloud AV so definitely it will protect better online as it can connect to their server to perform other advanced analysis. But I find it offline protection good too & it updates often too. I think they keep smart local databases like most prevalent & latest malware signatures for offline protection.

Running light & without any probs here on Win 7 64 Bits.

They call it essential antivirus without additional things so no configs, maintenance, etc... They should also remove the requirement to login.

Excellent protection for average users.

by Chiron on 21. January 2014 - 4:09  (113798)

Thank you very much for this test. I was also under the impression that the free version of Bitdefender was very effective, and I'm glad to see that your test upholds that belief.

Thank you.

by naren on 21. January 2014 - 6:31  (113802)

Nowadays I am testing BD Free often to confirm it provides the same protection/detection as BD Paid.

In my tests it seems to provide same protection/detection as paid.

Its good BD people provided same protection & not limited protection.

I find it excellent for average users with no configs, maintenance, etc... with excellent protection.

Hope they remove the login thing.

Lets see when you test how you find it.

by Chiron on 21. January 2014 - 13:10  (113822)

Thank you.

by shunima on 7. January 2014 - 4:13  (113434)

As for many others (see Avast's own forum) an update to Avast 2014 made my system unstable, messed with my network connections and made the Laptop (WIN 7 pro) almost unusable during the holiday season. Few days of attempts to fix this didn't help so finally it was bye bye Avast. All the other threats about Avast 2014 indicate that lots of us became beta testers of a produce not mature enough for a full release. I used Avast for almost 5 years and was always very happy. That unfortunately changed around Christmas but what worried me was that I was not alone with it. I changed to Bitdefender free. Works great (the fact that you can't set anything manually is a bit challenging to accept though :-) )is lightweight, no annoying purchase offers upon startup and does not render the Winpatrol popups Avast triggered from time to time (which is making the misses happy) Two weeks with Bitdefender and so far, I won't go back.

by lauriowayne on 2. January 2014 - 8:41  (113340)

even though AVAST 2014 is one of the best free antivirus tool available in the market however, my last system check even if it is updated, the version of AVAST fails to detect common viruses than that MICROSOFT SECURITY ESSENTIALS do.And it was only " I dont know why?

by MidnightCowboy on 2. January 2014 - 10:10  (113346)

There are several threads about the Nuqel worm in the Avast! forum going back to 2010 but the information they contain is not that comprehensive. Nevertheless it appears this malware is still being missed by Avast! Possibly this is because the code of the worm is being constantly changed into new "variants".

One recommendation is to consider an additional program that protects specifically against malware that uses USB devices to spread. MD - Site Manager.

by sicknero on 2. January 2014 - 23:47  (113366)

Thanks for the rec, never heard of that one before.

I've had it running all day on two machines alongside Avast ... it seems very light and well behaved so far, tomorrow I'll see if I can find any reports on how well it performs and what exactly it does do.

by MidnightCowboy on 3. January 2014 - 4:12  (113369)

Your welcome. :)

There are comments about it here:

There are also recommendations for it in other places, including the Avast! forum.

As ever, this will be another tool to help in the battle against Windows malware in the knowledge that no one single product ever can. MC Site Manager.

by vellen on 1. January 2014 - 19:07  (113319)

Avast is the best free antivirus nowadays. I have it on multiple computers for more than 2 years, and had NO problems with viruses at ALL. I work as a PC support, and install Avast Free Antivirus to my clients too.

by please55 on 13. December 2013 - 18:32  (112932)

What are your thoughts on ZoneAlarm® Free Antivirus + Firewall? I don't notice it on this list or the other 'Best Security List' thread.

I'd like to pick up a firewall as well and the package seems tempting but I haven't used ZoneAlarm in years and I don't know what the protection rate is like on this particular product is like.

by mehman on 3. December 2013 - 6:48  (112728)

In the quick selection guide, for Avira you mention that both 32 and 64 bit versions available. However, it should be 32 bit but 64 bit compatible. Since there is no 64 bit version for Avira.

Do let me know in case I am wrong with my observation.

by JonathanT on 7. December 2013 - 7:14  (112814)

Looks like you are right, nice pick up. :)

by Lumino on 20. November 2013 - 14:01  (112407)


In your review you say about Panda,

"Detection rates of real-world malware is slightly lower"

Yet according to rigorous tests such as this one in AV Comparatives from October

Panda has the best protection of all Antiviruses, better than the two above it.

by JonathanT on 23. November 2013 - 2:51  (112468)

You are indeed correct. Based on the various tests available I'd say Panda scores 2nd highest, I will edit the comment. Having said that, I'd like to reiterate that all the AV's listed here provide excellent protection for the average user.

by MikeR on 18. November 2013 - 20:02  (112352)

Just a note to say that I'm getting fed up to the teeth with Panda Cloud AV. Ever since it was released, it has ticked away quietly behind the scenes. No fuss (not much information, either, but in terms of actually doing its job, no complaints from me.)

I've no idea what has happened to the company recently, but for the past week, every day -- every day, mark you -- Panda has splashed an alert across my screen when I'm the middle of doing something saying 'Updates are awaiting install'. . . and then after the installation is complete, another screen says 'Restart your computer now' (because Panda Cloud AV won't function again until you do: as WinPatrol confirms, if you don't stop whast you;re doing and re-boot, there's no AV protection on your cpomputer at all.)

I really cannot get my head around why any AV outfit would wish to embark on so preposterously disruptive a route as this: day after day. update after update, and each one requires the user to stop what they're doing and re-boot otherwise their computer is unprotected???

That's never been the case with ANY AV publisher I've ever dealt with, except where a completely new version has been produced and a major upgrade neeeds to be carried out. But Panda seems incapable of determining the difference between upgrade and update. I really would very much like to know what the heck is going on here because an antivirus which mandates the user to reboot EVERY DAY in order to complete an update is of no use to anyone.

by Thomas J Thomas on 21. November 2013 - 14:06  (112434)

Hiya mike I read your thread with interest.

Just to let you know I also have Panda Cloud AV Free Edition, and nothing like you have described is happening to me, Its still behaving as its suppose to.

Have you thought of downloading the latest version to your desktop, Then removing your current version completely, and then of course install the latest version.

I say this as....surely if these problems that you are having where universal then it should be affecting everyone including me.

Anyway good luck, and please note I have provided FEEDBACK and not CRITICISM, and I hope you take it in the spirit in which it was meant.

( I also have WinPatrol AND I prefer Scotty as a round icon on the task-bar not the square lol )

by West Swan on 14. November 2013 - 2:18  (112209)


It is interesting that you recommend Microsoft Security Essentials for average users.

Windows Secrets, the website that Gizmo used to be a senior editor of, says that it is really only suitable for 'geeks' and those who use safe surfing practices. For average users they recommend other antivirus.

Oh yeah, I'm not saying you or they are wrong, just pointing out that even experts differ in their opinions :-)

I for one use Avast. I make sure to change all the settings so that it asks me first before deleting or repairing or quarantining infected files etc.



by AJNorth on 11. November 2013 - 15:53  (112162)

MS have updated their Microsoft Security Essentials to version 4.4.304.0 (digitally signed 2013.10.23); not able to locate a changelog at the time of this posting.

by CuriousJM on 5. November 2013 - 9:41  (112033)

Upgraded to Windows 8.1 Pro from Windows 8 and Avast has been deleted/removed. It seems it is not compatible with Windows 8.1

Please suggest a good AV which is compatible with windows 8.1

Currently I have to depend on Windows Defender which slows down the system

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