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 GJW on 5. November 2013 - 10:12  (112038)

Avast 2014 is working properly on Windows 8.1. You used likely an older version of avast. So, you just need to download and install avast 2014.

by CuriousJM on 29. December 2013 - 3:46  (112042)

Thanks GJW for the info;

Avast was set to update automatically (both programme well as data base) so I presumed it was the latest version. However Windows 8.1 removed/deleted Avast without any warning. I noticed it only when Action Centre showed a red flag that System was unprotected.

I tried to re-install Avast but couldn't because of compatibility issue. Perhaps the installation exe file was older version and had I downloaded the latest version it may have worked.

Any way for time being I have downloaded and installed Avira.

by innn on 1. November 2013 - 5:39  (111924)

I don't understand . Do people still use MSE ? I thought that product is for past windwos versions , so Microsoft does not put any more effort or other kind of investment into a DEAD product.
I use Windows 8 now and it has Defender built-in and I cannot complain about it. Now that is up to date in its development. It is taken care of. Though, here there's no mention of it but of its moribund predecessor.
If you still like to use older Windows versions you HAVE TO install 3rd party such as those mentioned on this page. I concur with all the others that MSE does not belong here anymore. Am I wrong? Please enlighten me.

by MidnightCowboy on 1. November 2013 - 6:19  (111925)

I have a whole bunch of people, friends, neighbors and some ex customers all using MSE without getting infected. What exactly are you basing your query on? MC - Site Manager.

by liubomirwm on 27. October 2013 - 10:41  (111799)

JonathanT, i can't understand why you put Microsoft Security Essentials above Avira and AVG. They are better. Also Avira and AVG are better than Panda.

by JonathanT on 1. November 2013 - 9:17  (111929)

It's very difficult to categorically state one AV is 'better' than another. Generally speaking all the AV's listed here provide adequate protection for PC's provided some common sense and safe habits are used. Also, this article is geared more towards average users who want a user friendly solution, of which I like MSE. I do mention that AntiVir has excellent detection rates.

by sepulchre on 27. October 2013 - 4:38  (111790)


I've used Avast for years with good results (no viruses - good protection, etc.) but I've become disenchanted with them. Lately, the last year or so, they have become more and more involved with Google. That's okay I suppose except that the last time I updated the program it installed Chrome on my machine without giving me a choice. As far as I'm concerned that's tantamount to being an invasion - the very thing the program is supposed to protect against!

Also, it has become harder and harder to do manual updates. Automatic are fine, until the day you are recording a guitar part and in the middle of the best take there comes a "update successful" voice. Yes, the audio can be turned off but I don't want Anything going on while recording. And it's constantly nagging to turn auto-update on.

That's really why I'm here; to find a different AV that won't become a virus itself like one of the big names did. (Thought I'd never get that off my machine.) So maybe Avira. Guess I'll give that a shot.

by sepulchre on 27. October 2013 - 6:40  (111793)

Okay, after 2 1/2 hours of struggling with Avira I never could get web protection to work. So I went back to Avast. But now they charge for features I used to get for free... I mean I got those features 3 hours ago and now they want to charge.

Oh yeah, and they installed Google Chrome again without even telling me they would much less giving me a choice!

So maybe I'll just have to pay for protection (though until a few hours ago I got the best I ever had for free . . except for the Chrome thing). But you can bet I will NOT get Avast. [Commercial reference removed]

But it really stinks that the guys I used to trust are trying to stick it to me now. I guess Google bought them so the good times are gone.

by Anupam on 27. October 2013 - 8:27  (111795)

There are clear checkboxes on the installation window to opt-out of Google Chrome, if you don't want it installed on your system.

In case you update Avast via its internal updater to a new version, then too, after updating, a window pops up where you can opt-out of Google Chrome.

Maybe you missed those?

Avast has a free version, since long time, and it continues to have it. So, again, maybe you downloaded the wrong setup file?

Avast still remains an excellent choice amongst free antivirus.

by AJNorth on 11. October 2013 - 16:56  (111422)

Might Lavasoft's Ad-Aware Free Antivirus + 11 be placed in the queue for future consideration?

They have replaced their Viper-based scanning engine with one from Bitdefender, and v.11 has garnered a positive review from CNET's Editor (and several users) -- .



by windyctyprog on 22. October 2013 - 14:25  (111670)


I just went through a miserable week with Ad-Aware...

I downloaded V10.5 a week ago Friday, installation went well, light on resources, didn't seem to slow down any application.

On Monday, V11 was released and things went down hill from there.

It was a mess.

On Wednesday they released another version, not an update, but another version.

I had all kinds of issues, I had to start monitoring manually, the tray, a separate .exe file, would never initialize, nothing would work.

I went to the forum, they had me delete services and other components they said were from Version 9 (how could this be, because I never installed anything from Lavasoft before V10.5).

This was supposed to be the root cause of the problems.

After I deleted what they said was a "service" from V9, nothing ever worked again - I couldn't get it to even manually start.

I also don't like the idea of having their browser protection software included, frankly I never understood if it was initialized or not. I know the toolbar was not installed, but as for the software running, I don't know.

It was listed as a separately installed program in both Windows Ad/Remove and in Geek's removal program, and even after I uninstalled Ad-Aware, I had to remove the Browser Protection separately.

I am not going to reinstall it.

by AJNorth on 24. October 2013 - 20:31  (111730)


Thanks for taking the time to detail your experience with Ad-Aware Free A/V+ 11; I'm sorry to hear that it was so miserable (it appears that Ad-Aware Free Antivirus+ 11.0.4516.0 is the current version, released on 2013.10.09).

That version 11 currently garners an overall user rating of 4/5 stars (from 29 reviews) at CNET, perhaps your difficulties were in some way related to your particular system and configuration (another positive review was posted by Thetechhacker --

In any case, it will be interesting to see both what additional formal tests reveal and other users' experiences over time are (to be fair, I have not experimented with it yet).

Take care.



by JonathanT on 18. October 2013 - 5:20  (111548)

Thanks for that AJ, I'll definitely take that into consideration.

by AJNorth on 26. October 2013 - 19:09  (111780)

Hello JT,

There's one other free application I've recently read about that may be worth a look when you've the time, CYSEC Free Anti-Virus, which garnered a very positive review from the UK publication Security Magazine -- .



by MidnightCowboy on 26. October 2013 - 21:28  (111783)

No information at all about how CYSEC was tested, and against what. Unlike Avast! and AVG however, it has no web protection or email security so in the real world it will be practically useless. It also requires the user to download a separate installer every time they want to do a full system scan. IMO users will be better off with one of the more complete products listed in the review above and using VirusTotal for secondary opinions. MC - Site Manager.

by AJNorth on 27. October 2013 - 6:36  (111792)

Thanks, MC.

by Rolandkeys on 9. October 2013 - 3:55  (111327)

Thanks for an excellent site,am currently testing 360 internet security,seems very good and light on the system,run this with malwarebytes free and windows firewall,comodo dns server,privdog and wot,Firefox.

by Rolandkeys on 14. October 2013 - 14:55  (111481)

too many false positives will,go back to Panda cloud av

by searchlight on 8. October 2013 - 19:50  (111321)

After reading several positive reviews of Microsoft Security Essentials, I decided to give it a shot thinking that my PC would be well protected.

I then came across this article today which I think should be shared will the readers of this forum who believed in MSE. After reading it, I quickly removed the product and switched to Avira Free for now which no longer has the nag screen.

Since there is now so much controversy, imagined or real concerning MSE and its effectiveness, I think Gizmo should remove MSE as a recommended product until we learn more.

by MidnightCowboy on 8. October 2013 - 22:57  (111325)

Presumably you did not read the other comments below? This is just another attempt to slag off MSE by taking what Microsoft actually "said" out of context. In fact this is just copied verbatim from PC Pro as indicated at the bottom of their article.

There is nothing more to learn from this other than Microsoft are being more honest about the capabilities of a single security product than other vendors. They already explained their strategy here.

False positives also remain an issue with other products, this being just one recent example.

You will also find plenty of reported infections by users of every antivirus product, including Avira. :) MC - Site Manager.

by searchlight on 9. October 2013 - 5:37  (111329)

If you like MSE, then stick with it. It is just a matter of opinion.

by searchlight on 9. October 2013 - 5:35  (111328)

I did read the comments, and the person to who you refer in your quote is different than the one in the quote I mentioned.

Regardless, if Microsoft Programming or Software Managers cannot get their stories straight, they both seem contradictory to me, I would rather deal with a product that is more proven and established as effective.

by MidnightCowboy on 9. October 2013 - 6:16  (111331)

IMO this is prime example of how the media are able to manipulate readers into believing something that isn't true. The quotes from Microsoft in the article you referred to are no different (of course) from the source they were copied from.

The fact remains that no one security product will protect users from everything no matter if the vendor calls it "360", "Total" or anything else that sounds like it will.

Member cybersun comments below that he has used MSE for three years without any issues, and yet was considering changing on the strength of this article. This is what these folks want you to do of course because the revenue they generate does not come from MSE but from the advertising and so called "offers" they promote for paid antivirus. This is just tabloid journalism come to tech media. Maybe the author used to work for the Sunday Sport. :D MC - Site Manager.

by Tod on 24. October 2013 - 7:56  (111718)

"The fact remains that no one security product will protect users from everything no matter if the vendor calls it "360", "Total" or anything else that sounds like it will."

I'm a little confused now. I was wondering which one would be better, Bitdefender or Avast 2014. Do you think both are so good as each other?

by MidnightCowboy on 24. October 2013 - 8:07  (111719)

Both are very different in that Avast! is a full on application whereas Bitdefender adopts a more minimalistic approach. In this respect the configuration options are limited which might not suit users wanting to have total control of their security configuration. The detection power of Bitdefender however is top notch so overall the protection performance will be very similar. Both program though will need some supplementary assistance to achieve optimum system protection. See the link below for some suggestions. MC - Site Manager.

by Tod on 24. October 2013 - 8:53  (111722)

Thanks, MC. I checked that page. Very informative! It helps me a lot.

by searchlight on 9. October 2013 - 13:45  (111335)

If you look closely at the articles, these are not examples of media manipulating readers but contradictory quotes by Microsoft's own people. That being said, Microsoft should be making one consistant statement across the board regardless of test results or efficacy debates.

If a company cannot, will, or appears not, to stand behind their security product, then I personally am not comfortable using it.

Like I intimated earlier, useage boils down to personal preference.

by cybersun on 5. October 2013 - 17:53  (111264)

Listen, I am a bit surprised to read your review. I just ended up reading an article in HOW TO GEEK where they specifically say that even MS recommends now to use 3rd party AV, as their MSE now ranks last in the list of FREE AV Software. Isn't that info available to you also? In fact all agree in saying that AVAST is the best Free AV but has a loaded interface... I would be thankful to read any comments by knowledgeable individuals on this topic. I have trusted MSE for over 3 years now, I haven't had any issues, but reports such as the one in HOW TO GEEKS (yesterday newsletter) worries me. Of course MS reputation for their blunders help in not feeling to safe about MSE or its future in fact.

by MidnightCowboy on 5. October 2013 - 23:41  (111266)

This website and others are taking what Microsoft actually "said" out of context. Most of what was "said" relates to the ability of MSE to pass tests which is what they and other vendors spent a lot of resources on previously. In yours and my real world, these tests are as irrelevant to antivirus programs as Matousec is to firewalls. You could of course keep a log of your internet and other computer activity activity, spend 6 hours a day comparing this with what your antivirus "fails" on in various tests, find one that matches and say Oh yeah, I went to this site on 19th July so maybe I was at risk. This of course is impossible and would also be a ludicrous exercise, even if it was.

What Microsoft did say was this:

"It’s not as efficient to have one kind of weapon. "Like anything you must have that diversity. It’s a weakness to just have one."

This is what we here have been saying ever since the site was set up. Multiple layers are necessary in order to provide optimum protection including browser extensions, a DNS filter and the adoption of safe surfing practices. No one single product can achieve this on it's own although many vendors claim to. This is described in more detail here:

The bottom line is, if you have been using MSE for three years and not been infected, why now should you suddenly be at risk? MC - Site Manager.

by Phylis Sophical on 2. October 2013 - 17:00  (111179)

Windows Security Essentials does not run on Win8. Windows Defender runs by default and now includes virus detection.

A good review of Defender and other Win8 protections can be found here:
However, they too state that "Microsoft has said that Defender on Windows 8 provides an 'acceptable minimum level of protection', and that it will disable itself automatically if another antivirus suite is installed"
Maybe MS is just being honest. :)

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