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. However, 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 eventually. 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 due to unintended conflicts. For my advice on how to compensate for these weakness of antivirus products 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 arsenal.


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 I do of course admit that 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:

10/7/2014-Re-inserted explicit statement mentioning that I am a volunteer moderator (not employee) on the Comodo forums.

10/9/2014-Linked to instructions on how to make sure Bitdefender Free can be installed in English, and added MSE to list of unsuitable AV's.

11/14/2014-Added additional information about Bitdefender Free.

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. My criteria is entirely based on protection, not cleaning. Therefore, if you believe your computer may be infected please first see my article on How to Know If Your Computer Is Infected before continuing to read the rest of this article.


I have located reputable 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 spanning back over the last two years. 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 (which has the exact same protection for its Free and Paid versions), are often quite different from those for the Free versions. Many marketing teams try to cloud this difference, but for the purposes of getting the most reliable information I am strict about this. Unless it can be explicitly proven that every protection mechanism is exactly identical to the free version the results for paid products are not considered in this analysis.

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 (CIS), which is also free and includes a firewall in addition to all other components which already come with Comodo Antivirus.

Firstly, I will note that I am a volunteer moderator (not employee) on the Comodo forums. However, this is certainly not the reason I chose this for the number one position. 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. This is because it maintains a white-list of known safe applications. Then, all unknown applications, which include all unrecognized malware, will be sandboxed and isolated from the rest of the system. Thus, this product provides very strong protection against even zero-day malware.

Comodo Antivirus also uses the cloud to facilitate the detection of the most recent malware, as do many other Free Antiviruses reviewed in this article. 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, please see my notes in the Quick Selection guide for advice on how to avoid unwanted software during installation.


Panda Cloud AntivirusPanda Cloud Antivirus is an excellent choice for average users, who may find Comodo Antivirus 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. The protection offered by this product is very strong. However, do note that it will auto-quarantine files which it believes to be dangerous.




Avast! Free AntivirusAvast! Free Antivirus 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 Web of Trust, 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.


AVG Anti-Virus Free EditionAVG Anti-Virus Free Edition is also a good 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).





360 Total Security is also a good choice for average users. Although it has gotten some very stellar reviews, the results I found from looking at the results from the testing agencies referenced earlier in this article show that the protection it provides is roughly the same as AVG, but certainly not as effective as Comodo, Panda, or Avast. This product uses multiple antivirus engines to detect malware. It has cloud protection, and also uses the Avira and BitDefender engines, although these are not enabled by default. For more information about this antivirus, see the separate article on this page.

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, Avira provides 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 very similar the commercial product, although there are some tweaks. However, the level of protection provided has not been shown conclusively to be identical with the paid version, which is why I did not use the results for the paid version in my analysis. Bitdefender Free has both local and cloud-based definitions. Thus, users always have access to the most up-to-date definitions. It also has an effective heuristics engine, and uses a component called the Active Virus Control to monitor applications in real-time for suspicious behaviors. In addition it also has a webshield, which seems quite effective at protecting users from both malware infested and phishing sites.

The user interface for this product is very minimalist. Thus, it may be attractive for novice users, although more advanced users may be frustrated at the lack of customization. However, it has no offline installer, and it also requires registration to continue using it past 30 days. 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. Also, note that if you are having trouble getting Bitdefender Antivirus Free Edition to install in English please follow the steps in this post.


Please help us by rating this review

End-Note: Please note that I also looked into Forticlient , Kingsoft, and Microsoft Security Essentials. However, I found that the protection offered by these products is subpar. Thus, if you are considering using Forticlient or Kingsoft I would strongly recommend that you instead consider another of the products reviewed in this article.

Related Products and Links

Other Articles By Chiron

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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). Also, Comodo Secure DNS, which is offered with Comodo Antivirus during installation, tends to have many false positives. Thus, I would suggest that you untick the option to Enable Comodo Secure DNS during installation.
Version 6.x
32 and 64 bit versions available
Unrestricted freeware
There is no portable version of this product available.
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, I would suggest that you untick the option to Enable Comodo Secure DNS during installation. It tends to falsely block many safe pages. 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.
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: Forum:
Windows 2000, Windows XP, Windows Vista, Windows 7, Windows 8.x, Mac OS

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.
Forum for support
Windows 2000, Windows XP, Windows Vista, Windows 7, Windows 8.x

360 Total Security

Runs as a stand-alone program on a user's computer
Contains many engines for malware detection.
Avira and Bitdefender engines are not enabled by default.
32 bit but 64 bit compatible
Unrestricted freeware
There is no portable version of this product available.

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, no offline installer, requires registration after first 30 days
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.

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Average: 4.3 (2042 votes)


As sicknero mentioned, did you register the product? Regardless, it should still be able to be removed (and if it can't this sounds like a bug), but the reason it's nagging could very well be because of the required registration. Thanks.

The free version of Avast requires that you register with them to use it for more than 30 days.

I'm guessing that you didn't do that?

What about Qihu 360 Internet Security?

Only products with a proven history over a long period outside of their domestic environment are likely to be considered for this review. MC - Site Manager.

Have been testing AVG, Avast! & Avira. So my 2 cents, for what its worth:

1. Whilst AVG certainly is very capable and suitable for the vast majority of users, it does tend to be a bit "heavy" and slow, but all round a solid product.

2. Avast! may well be rated highly, BUT be warned.... its a bandwidth hog, doing all sorts of strange things in the background. At first I thought it was a bug or something weird going on... but a quick search on Google shows that this is well known. If you are using 3G or any form of controlled bandwidth, suggest you leave Avast! well alone! Setting to a minimum file only protection did not seem to help the situation either.

3. Avira.... have since 2013 removed their intrusive ads (This needs to be updated in the above summary). I currently use this Anti-Virus, and have no issues so far!

I have removed the warning about Avira from the article. Apparently they now provide free users access to their cloud as well. I have updated the article to mention this as well. As for the other products, I will be updating this article (once I have more time) to better differentiate between the real-world protection offered by the various products. To do this I will draw on the results from several testing agencies. However, I am very busy right now and not sure when I'll find enough time for a drastic rewrite and research which this necessitates. That said, it will happen eventually. I was not aware of the issues which Avast causes on systems with slow internet. I assume that is likely caused by cloud-based activities. Has anyone else run into a lot of problems with Avast hogging the band-width? If so I'll update the article to warn about that. Thank you.

Avira Free Antivirus has been updated to version (2014.03.04; 132 MB).

(Again, the update nag screen has been eliminated.)

Thank you for bringing this to my attention. I have now edited the information in the article. Let me know if you still see any issues. Thanks.

You're most welcome, Chiron (and thanks for updating the Avira description!).

Incidentally, Avira have added two additional enhancements by incorporating their "Protection Cloud" and "Browser Safety" features in their free A-V - (it will be interesting to see what effects this might have on future testing results...).


P.S. In case you don't follow his articles, Neil Rubenking, Lead Analyst for Security over at PC Magazine, does his own extensive in-house testing (along with relying on results from the various testing labs); his most recent overview of free anti-malware solutions (2014.01.08) can be found at,2817,2388652,00.asp . (Should you ever wish to contact him, Mr. Rubenking is very gracious about answering emails.)

Thanks. I've now added that it also includes the cloud. However, I did not see any indication that the new browser safety addition is yet included. It seems to be in Beta. Thus, I did not add that to the article yet. As for updating this article to better compare the products, I am still trying to find the time to do that. I have been very busy lately, but do still plan to update this article such that it will better differentiate between the real-world protection offered by these various products. At that time I'll be using the results from multiple testing agencies. Thank you.


I should say online activation is "optional".


I agree with George.J. Although it will run fine for 30 days without registration, it will stop running after that time runs out. Therefore, that is why I say that it requires registration. If you have any questions about that please feel free to ask. Thanks.
Avast will run free only for 30 days unless you've activated it. Upon activation you get a 365 day license.

Avast! Free Antivirus was updated to version 9.0.2013 (86 MB) on 2014.01.23.

Thanks for letting me know about this. I have now updated the information in the article.

I am using Bitdefender, due to all the excellent reviews of their product. I did have a problem with Ccleaner locking up my system whenever I did a scan.
According to the forums on Bitdefender, to avoid this problem, all you have to do is turn off the virus shield on Bitdefender, whenever you run a scan with Ccleaner. Since I started turning off the virus shield, to run Ccleaner, I have not had any problems. Just make sure you turn it back on when you finish cleaning with Ccleaner. I love this anti virus, and I do not mind a little extra work, to keep it on my computer. I wrote this as a help to those that maybe having the same conflict with Ccleaner. I hope I was of some help with this issue.

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. Thanks.


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.

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.

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?

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.

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).

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. Thanks.

My pleasure, Chiron, and welcome aboard!


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.
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. Thanks.

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.

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.

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.

Thank you.