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 jamesedwards399 on 16. May 2013 - 7:33  (107777)

There is some antivirus which slows down PC a bit as it uses more resource in your system while some don’t. Norton, MSE are such type of antivirus tools which will slow down your system. Immunet Free, Avira, Bitdefender etc. Are some antivirus which does not have much effect on computer speed and performance. Every antivirus tool automatically updates itself but you need to check automatic update box in software’s setting.

I personally use Immunet Free, here is a free download link to it -

by e-j on 16. May 2013 - 14:00  (107784)
by George.J on 16. May 2013 - 16:17  (107787)

Not sure why Avast is at the top, even though Webroot clearly is lighter from the tests and is regarded to be the lightest antivirus of all time, both in terms of installation size and while idle/scanning..

by cavehomme on 13. July 2013 - 10:22  (109195)

Webroot is very good, but it's not free.

by George.J on 18. May 2013 - 0:05  (107818)

I take back my words. I found that Avast flushes memory every 10 sec so the memory consumption will always be back to 5MB during scans (and never above 20MB), which I think is a great feature.

by AJNorth on 13. May 2013 - 21:20  (107724)

Avira have updated their Free Antivirus to v13.0.0.3640 (2013.05.07), 97.5 MB (off-line executable), a roll-up of product updates since the previous version's release -- (a 2 MB on-line installer is also available, as well as the User Manual).

Many find the pop-up nag screen that occurs with each update particularly annoying; a web search will provide the means by which to address this issue.

by JonathanT on 18. May 2013 - 1:57  (107821)

Thanks for the heads up!

by Panzer on 6. May 2013 - 8:38  (107482)
by e-j on 6. May 2013 - 14:24  (107496)

norton dns says that link is a malicious web site.

by e-j on 6. May 2013 - 17:00  (107497)

that's weird, now it doesn't have it blocked. maybe just a false positive?

by MidnightCowboy on 7. May 2013 - 0:27  (107501)
by e-j on 7. May 2013 - 14:18  (107525)

thanks for the info mc.
keep up the good work.

by Paxmilitaris on 2. May 2013 - 5:50  (107418)

I'm using MSE on Win XP, but i think it may be slowing my computer.

Also, you mention that "It automatically updates" and that for me is false. Windows update works but i have to manualy update MSE.

It's also weird that the security center sometimes forgets that MSE is running and then when i update it, it remembers. MSE also forgets that it has run a scan, saying it hasn't scanned in a long time, when the last scan says last night or some such.

I hate microsoft, but that's weird even for them.

by Anupam on 2. May 2013 - 5:54  (107419)

Yes, MSE does slow down the computer a bit, I have observed that too.. specially in opening the folders with exes, and in other areas too.

About you facing other problems, I think you should re-install it once again. MSE updates via Windows Updates without any problems, and the scan time should also hold.

However, I have seen that MSE updates occur very very slowly sometimes, like painfully slow.

by AJNorth on 13. May 2013 - 21:40  (107725)

For what it may be worth, I have had Avira Free A/V running on about a dozen Windows boxes for several years, seven running XP (both Home and Pro). On machines with less than 1 GB of RAM and / or single-core, single-threaded processors, updates and scans do significantly impact performance.

The updates are a relatively minor issue, as they rarely take more than two minutes to completely install (unless one happens to be performing a processor-intensive task, such as video trans-coding); scans can always be paused and resumed later (and Avira A/V is highly-configurable in Expert mode, where, for example, the scan priority can be adjusted).

Without exception, there have been no malware infections in more than seventy machine-years of use. (To be fair, each machine also runs the Comodo Firewall, the Secunia PSI, WinPatrol, Firefox with NoScript, the Web Of Trust, SpywareBlaster and a secure DNS.)

by Paxmilitaris on 2. May 2013 - 6:14  (107420)

Would Avast or Antivir be better for computer performance?

by Anupam on 2. May 2013 - 6:54  (107422)

Yea, Avast or Avira are better :). Although, if it's a low end computer with P-III or something, or 512MB RAM, performance will still be affected a bit.

by freestuffrocks on 23. April 2013 - 11:57  (107290)

Any views on the antivirus component of Comodo Internet Security? I never thought it was that good (I use Avast free + Comodo firewall) but recently it's been getting good reviews.

by MidnightCowboy on 23. April 2013 - 12:26  (107291)

Well in this test it came close to bottom although these things should always be researched a bit more deeply.

Comodo's focus has always been on prevention as opposed to pure detection and when configured correctly by knowledgeable users will give first class protection. Achieving this status for average users though is quite a climb so unless they are prepared to follow the guides and read Comodo's own documentation, IMO they will be better off with one of the other solutions listed here. MC - Site Manager.

by naren on 24. April 2013 - 16:29  (107310)

CIS version 6 has eliminated popups & now is easy enough for any/all users. AV has improved a lot & at par with other top AVs. Upcoming feature Valkyrie is excellent in detection/zeroday detection with very very very few/rare FPs.

About the AV-Test - Comodo Dev, Egemen posted in Comodo forum ---

Let me Share with you the detailed results:

av-test tested CIS 6 for 2 months, January 2013 and February 2013.

Here are the results:

January 2013:

Completely blocked malware attacks: 47
Partially blocked malware attacks: 7
Attacks not blocked (system got infected): 2
Protection: 54/56 - 96%

Detection Rate: 7423/ 7426 - 99.96%
False Positives: 22/293897 - 0.0074%

February 2013:

Completely blocked malware attacks: 62
Partially blocked malware attacks: 7
Attacks not blocked (system got infected): 0
Protection: 69/69 - 100%
False Positives(Behavior Blocker alerts):5/70 7%

Detection Rate: 10839/ 10841- 99.98%
False Positives: 22/308887- 0.0071%

As you see CAV detection rate is 99.9%. False positive rate is pretty low.
The only thing i personally care is the fact that in January, there were 2 reported infections despite CIS and these are fixed.

We are not allowed to disclose the others' results so hence cant compare with others too much. The main reason we look low on is false positive rate. Not the protection, not the usability you may think.

Let other vendors publish their own results and you guys compare and decide. When i interpret these results, i see a solid product within top 4 and in this top 4 CIS is the ONLY free one.

by MidnightCowboy on 25. April 2013 - 0:35  (107321)

Unfortunately though it is necessary to compare apples with apples and not the orchard owner's interpretation of what came off the trees. In this respect AV-Test clearly states that:

Protection against 0-day malware attacks, inclusive of web and e-mail threats (Real-World Testing) was 84% and 90% for Jan/Feb when the industry average is 95%.


False blockages of certain actions carried out whilst installing and using legitimate software scored 5 when the industry average is only 1.

False positive detections were also more than three times the industry average.

On this basis, the ZoneAalrm test results (which is also free) are higher:

Of course you can argue all day about the relevance of these tests (and indeed others) to average home users but that is not the point in question here.

Also, when I look at these things I do not perform the exercise alone. In addition to my own installation I impose the software on a range of folks including friends, neighbors and ex customers who like to feel they are contributing to a service. The overwhelming feedback I get regarding CIS is how difficult it is to understand and configure. Admittedly this centers mainly on settings above the default configuration but the fact these are there suggests to any right minded person that the protection level must be greater when these are employed, otherwise why have them? This is when the majority of users get lost, and making wrong choices has the potential to damage their system or protection level thereof.

by naren on 26. April 2013 - 13:31  (107352)

False blockage mentioned in AV-Test, I think they are talking about programs autosandboxed that didn't worked. I dont know how they count malware blockage by autosandbox i.e they count it as protected or missed due to inert files remains? (autosandbox protects from malware but some inert files may be there as autosandbox is a restriction thing).

If programs autosandboxed didn't run is count as false blockage, I think they should also count malware (active malware) blockage by autosandbox as protected, any info on this?

Offcoz higher settings than default increases protection. But I would recommend default as its very effective & easy in real world scenario.

Users who find configuration thing difficult or hard to understand, they will find configuration thing with any products difficult. Such users are/should not be advised to do so, default settings are carefully prepared easy/effective set of settings for such users, configuration or advanced settings are for, as the name suggests "Advanced" or expert users.

by Rolandkeys on 20. April 2013 - 10:21  (107212)

Have been a happy Avast user for years until now with the Avast 8 causing problems,am now using Zone Alarm free antivirus and firewall on midnight cowboys advice,all seems well so far. Using an old xp system run this with Malwarebytes free.

by Anupam on 20. April 2013 - 10:23  (107222)

Please don't edit the comment again and again to bump it. What kind of problems did u face on Avast?

by Rolandkeys on 20. April 2013 - 10:48  (107225)

wasn't trying to bump it ,just spelling errors,the Avast 8 beta starting stalling on he scan.

by Anupam on 20. April 2013 - 11:44  (107226)

Well, since you use a beta version, you cannot really complain about it, can you? :). Beta versions are for testing purposes.

I have been using Avast 8 stable version, and I dont have any problems. Also, the releases generally take some time to stabilize because of different issues. So, it's best to wait for a while, and look at their forum to see if any issues are there. If there are not, then you can install the version, otherwise stick to the older version until the issues are resolved.

A new version of Avast 8 was out recently, but I have not updated yet for that reason.

by Rolandkeys on 21. April 2013 - 6:39  (107233)

Have sorted it out,reverted back to Avast 7,all fine at the moment.

by Anupam on 21. April 2013 - 7:27  (107234)

I am using the latest version of Avast 8 on my Windows 8 PC, and it's working really well. I have Avast 8.0.1483. It is not beta, it's a stable version.

by Rolandkeys on 20. April 2013 - 12:22  (107228)

Was'nt complaining was just looking for ideas, may go back to older version.

by Rolandkeys on 26. April 2013 - 1:34  (107240)

Had problems with the Avast 8,will go back to Avg free.

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