Best Free Antivirus Software

Other Language?
  Read this article in Spanish
  Read this article in Chinese
In a Hurry?
  Go straight to the Quick Selection Guide

Antivirus software provides an essential layer of protection from viruses, trojans, worms, spyware, adware, dialers, keyloggers, and rootkits. Don't let the name antivirus confuse you. These days every good antivirus has good detection rates for all forms of malware, not just viruses. The term malware includes viruses, trojans, worms, spyware, adware, dialers, keyloggers, rootkits, and any other software which performs malicious activities on a computer.


Sadly, the amount of malware currently in circulation is so large that no antivirus could possibly detect all of it. Despite vendor's claims, no single antivirus solution can detect nearly all new malware. There are some products out there, including some in this review, which include technologies which are able to adequately protect a computer, but any product which relies mainly on detection is statistically doomed to fail at some time. Also, using more than one real-time antivirus at the same time uses much more system resources, can cause system errors, and can even reduce protection. For my advice on how to compensate for these weakness of antivirus products, to a large extent, please see my other article about How to Stay Safe While Online. Having a good antivirus product does go a large way towards adequately protecting your computer, but in this day I would highly recommend that you add additional layers to your security.


Below I have reviewed some of the most effective Free Antivirus products currently on the market. In order to make this review more unbiased, although of course my own intuition and experience does affect my judgment as well, I came up with a particular methodology for comparing these products. This methodology is described in the following section.

Methodology For Comparing Products

The main motivation behind why I came up with this particular methodology for this review is that I value system protection against real world threats above all other categories by which an antivirus is commonly judged. It does not matter to me whether an antivirus protects the user by detecting malware, blocking dangerous sites, behavioral analysis, sandboxing, or any other approach. The most important thing is that at the end of the day your system is safe from infection. Thus, that is the attitude I have taken towards reviewing these products.


Therefore, I found Antivirus testing organizations which claim to test products against situations which resemble real-world situations. I narrowed these down by further requiring that the organizations have a relatively long record of producing good, seemingly unbiased, results. The organizations I ended up with, and therefore used for this review, are:



Dennis Technology Labs

From here I looked at all tests ranging to the beginning of 2013. However, if there were more than three tests within that range I used only the most recent three. Also, if given the choice between results from different operating systems, I chose that for the most popular operating system. At the moment Windows 7 is the most popular operating system.

Also, I only considered results if it was specifically the Free Version which was tested. This is because the results for the Paid Version of the products in this review, with the exception of Comodo Antivirus, are often quite different from those for the Free versions.

In addition, I did not count it against any of the products if they were not tested by multiple organizations. As long as they were tested by at least one, within the above-mentioned period, they were considered. This criteria was chosen because there are many reasons to choose not to participate in a test. Thus, it should not be held against the product if they were not tested by multiple agencies. However, if they were not tested by any, this makes it impossible to compare them in an unbiased fashion.


Once this data was collected, I then looked at the overall results for the Free Antivirus products discussed in this review, and ordered them mainly according to the quantitative results. However, my own knowledge of the products, and the reviews and experiences of others, were also considered. The results are presented and discussed below.

Discussion And Comparison

Comodo Antivirus is my top pick for advanced users or for Intermediate users who are okay with an antivirus software which will occasionally ask them for input. However, if you do not fall into those categories, or for any other reason find it to not be a good fit for you, then you will likely find my next pick suitable. Also, for those who prefer a complete solution, there is always Comodo Internet Security, which is also free and includes a firewall in addition to all other components which already come with Comodo Antivirus.

The reason I made this my top pick for advanced users or users who are okay with a somewhat talkative antivirus software, is because it is the only product which I feel confident saying that it will protect you against nearly 100% of real-world threats. I have a lot of experience with this product. I am a volunteer moderator on the Comodo forums and have been using it for a long time. I know this product very well, and am entirely confident in its ability to protect.

Comodo Antivirus uses the cloud to facilitate the detection of the most recent malware, as do many other Free Antiviruses reviewed in this article. However, Comodo also incorporates a Behavioral Blocker, which will automatically sandbox all software which it does not know for sure is safe. Thus, the user is protected from nearly all malware, which will either be detected by the antivirus component or sandboxed by the Behavioral Blocker. It will also analyze unknown applications for suspicious behavior, and alert the user accordingly.

However, as mentioned previously, users who do not want a somewhat talkative antivirus should continue to my next pick. Also, by default Comodo Antivirus has small advertisements (which can be disabled as shown here). Also, during installation users should be sure to click the Customize Installer option, which is near the bottom-left of the installation window. This will allow them to uncheck additional software, which the installer will automatically install with Comodo Antivirus unless unchecked. This software is not dangerous and includes a browser, and ad-blocking addon, and an optional paid service which would allow Comodo technicians to assist you with any computer problems you have. These, and a later option to change your homepage to support Comodo, can safely be unchecked during installation. Even with this extra hassle, this software is still my top pick, but I do wish they made the process simpler.


Avast! Free AntivirusAvast! Free Antivirus is has very good protection rates. Avast has many different protection shields, boot-time scanning, a behavioral blocker, an internet site ratings plugin, script malware protection, and access to cloud-based protection. It's arguable whether their ratings plugin offers comparable levels to WOT, but the script malware protection can prevent certain browser exploits, a feature not available in any of the other free AV's reviewed.

Avast is also relatively light on resources. However, do note that Avast requires a free registration to function after 30 days, and the default installation installs the Chrome browser unless you uncheck it. Also, note that the OpenCandy advertising component is integrated into the Software Updater tool in Avast. More information about OpenCandy can be read here. Thus, if a user selects this option during the install they will end up with OpenCandy on their computer. Please be very careful about this option if you choose to install 


Panda Cloud AntivirusPanda Cloud Antivirus is another excellent choice for average users, who may find both Comodo Antivirus and Avast too confusing. It has a simple interface, completely automated features, access to cloud-based protection, and has been shown to be very good at protecting a computer. Panda Cloud Antivirus has a behavioral blocker, web protection, and access to cloud-based protection, all of which will help increase your security.


AVG Anti-Virus Free EditionAVG Anti-Virus Free Edition is also a decent choice for average users. My analysis of the results, as discussed in the methodology section, does show that it does a decent job of protecting your computer. However, it appears that the above Antivirus products tend to do better. Also, it comes with advertisements (but they can be disabled).


Avira AntiVir Personal EditionAvira AntiVir Personal Edition is another product which has a very good reputation. However, the free version was not tested by any of the three testing organizations I referenced in my methodology. Therefore, I cannot currently recommend it above any of the previously mentioned products.

However, other comparative tests do show that it has very high detection rates for malware. Also, many users have used it and found that it is very effective. Also, users have access to cloud-based protection. AntiVir is certainly a good choice for a free antivirus, but due to the lack of real-world testing, at this time I cannot recommend it above the other products in this review. Hopefully in the future they will have the free version tested by these organizations as well.


Bitdefender Antivirus Free Edition

Bitdefender Antivirus Free Edition is another free antivirus product which has a very good reputation. However, the free version was not tested by any of the three testing organizations I referenced in my methodology. Therefore, I cannot recommend it above any of the previously mentioned products.

The engine for this product appears to be the same as for the commercial product. However, the level of protection provided has not been shown identical with the paid version, which is why I did not use the results for the paid version in my analysis. The user interface for this product is very minimalist. Thus, it may be attractive for novice users, though more advanced users may be frustrated at the lack of customization. Bitdefender Antivirus Free Edition is a good choice for a free antivirus, but due to the lack of real-world testing, at this time I cannot recommend it above the other products in this review. Hopefully in the future they will have the free version tested by these organizations as well.


Please help us by rating this review

Related Products and Links
Related Free Antivirus Software Articles

Related Security Articles

Have Your Say

Please visit our freeware forum to share and discuss your views and get advice on free security software, including antivirus software. To post in the forum you need to register first but that's quick and immediate.

Quick Selection Guide

Comodo Antivirus
Gizmo's Freeware award as the best product in its class!

Runs as a stand-alone program on a user's computer
This has full real-time protection capability, including real-time antivirus, behavioral blocking features, cloud-based protection, and an automatic sandboxing function which protects users from nearly all malware.
The automatic sandboxing function, although not very intrusive, may be too talkative for some users. Also, by default non-intrusive advertising is enabled (although it can easily be turned off).
Version 6.x
32 and 64 bit versions available
Unrestricted freeware
There is no portable version of this product available.
Windows XP, Windows Vista, Windows 7, Windows 8.x

Take care to avoid the installation of unwanted software during installation. To do this use the customized installer button, which is on the lower left-corner of the screen during installation. Additional software, including a browser, an ad-blocking addon, and an option paid service which would allow Comodo technicians to help you with computer problems, are all included by default.

Avast! Free Antivirus
Runs as a stand-alone program on a user's computer
This has full real-time capabilities, behavioral blocking features, script malware protection, and a low rate of false positives.
Default settings require certain user interaction. It is bundled with Chrome browser by default, and if not carefully avoided during installation the user may accidentally install OpenCandy (see discussion for clarification).
Version 9.x
32 bit but 64 bit compatible
Feature limited freeware
There is no portable version of this product available.
Windows 2000, Windows XP, Windows Vista, Windows 7, Windows 8.x, Mac OS

Take care to avoid the default inclusion of the Chrome browser and OpenCandy during the install process by using the custom install option. The attempt to install these will also be repeated at the program update if the automatic option is chosen.
Quick Start Guide:

Panda Cloud Antivirus
Combines a web service with a stand-alone program
High detection rate of malware, web protection, some behavioural blocker features
Detection rates of real-world malware is slightly lower
Version 2.x
32 and 64 bit versions available
Free for private use only
There is no portable version of this product available.
Windows XP, Windows Vista, Windows 7, Windows 8.x
AVG Anti-Virus Free
Runs as a stand-alone program on a user's computer
Behavioural blocker
Slightly lower signature detection rates
Version 2013.x
32 and 64 bit versions available
Free for private use only
There is no portable version of this product available.
Windows 2000, Windows XP, Windows Vista, Windows 7, Windows 8.x

Forum for support

Avira AntiVir Personal Edition
Runs as a stand-alone program on a user's computer
Outstanding detection of malware
Not the most user friendly
Version 14.x
32 bit but 64 bit compatible
Free for private use only
There is no portable version of this product available.
Windows 2000, Windows XP, Windows Vista, Windows 7, Windows 8.x
Bitdefender Antivirus Free Edition
Runs as a stand-alone program on a user's computer
High detection rates, very user friendly
Lack of customization
Version 1.x
32 bit but 64 bit compatible
Free for private or educational use only
There is no portable version of this product available.
Windows 2000, Windows XP, Windows Vista, Windows 7, Windows 8.x


This software category is maintained by volunteer editor Chiron. Registered members can contact the editor with any comments or questions they might have by clicking here.


free antivirus, best free antivirus, free antivirus programs, free antivirus program, antivirus software, free antivirus software,  antivirus program free, anti-virus programs, antivirus scanner, best antiviros, best antvirus

Back to the top of the article


Share this
Average: 4.3 (1965 votes)
Your rating: None


by George.J on 12. September 2013 - 2:16  (110662)


by RandyDoqa on 12. September 2013 - 0:52  (110658)

Can you please till me if Avast is still the best choice as free antivirus software or not, i am asking because in your review i noticed that you rated "Microsoft Security Essentials" and "Avira AntiVir Personal Edition" with 5 stars and "Avast! Free Antivirus" with 4.5, so i want to know if "Microsoft Security Essentials" is the best choice now or not, or it is "Avira AntiVir Personal Edition" or it is still "Avast! Free Antivirus"?

I follow your review for my choice so i want to know which is the best now.

And thank you so much for your review.

by JonathanT on 14. September 2013 - 5:03  (110700)

Avast is certainly one of the best choices, basically any of the major AVs provide good protection with good computing habits. :)
The rating shouldn't be displaying that, my bad.

by liubomirwm on 12. September 2013 - 9:04  (110668)

Hi RandyDoqa, of you take a look at my prevoius post you will understand that the 2 best free AVs are #1BitDefender AV free edition and #2avast free antivirus. BD free has no settings and no advanced features but it's using the same engine and definitions as the paid products of Bitdefender(AV of the year and best repair of the year) so it has the same detection as the paid products of BD. My favourite AV is Avast, it has many features, but it doesn't have the detection rate of Bitdefender. So the choice is yours- Bitdefender or avast(i mean that are the best free AVs in the world). Of course you can use other AVs but these are the ones i recommend. Oh, and don't believe that Qihoo 360 is better than these AVs, it has no chance against them. :)

by taylor1277 on 8. September 2013 - 7:12  (110590)

i found this here on your website,i have been using it for a month now and i would like to say that maybe its time we take one of the everyday we hear about antivirus programs that are bloated so badly today and help out those that brought me Unthreat Antivirus.Hope this isn't against the rules,but if anyone else out there is looking for a good antivirus,give this a try.thanks love the website.

by liubomirwm on 8. September 2013 - 12:48  (110596)

There is another great AV, Bitdefender (it is the Antivirus of the year according to AV-Comparatives and has won the Best Repair for 2012 award from AV-test) and it has a free version, which you can download from here: Note that you can't configure any of it's settings, but it takes care of everything automatically and discreetly using Top notch technologies). And, my favourite is Avast. It has more features than any other free AV. In the tests, Avast is outperforming every other free anttivirus program, incl. Your #1 selection, Avira. The only free AV which beats Avast is Bitdefender. And like they say- "It beats all viruses...and antiviruses. Always AWAKE) So, the #1 AV should be Bitdefender, and the second, my favourite Avast. Thank you for the great site, Ian!

Edit: MSE has a very very low detection, in fact, it has the lowest test results, LOL

by Looker on 23. August 2013 - 4:01  (110278)

I used Avira for several years. But Avira finally started upgrading itself on its own to v13 after bugging me everyday to do the upgrade (and me refusing). Not cool. Then it tells me to uninstall Spybot and (I think it was) Emisoft as they are "incompatible". Also not cool.

So fine. I uninstall Avira and start installing Avast. But I'm reading its eula and I get to the disturbing part below. It seems Avast is now spyware and DOES collect your personal info and provides it to its "business partners". VERY uncool!

Is this new? Do others find this objectionable, too? Am I misinterpreting something? Other parts of the eula were questionable as well.

[below is copied from eula]

"Notwithstanding anything to the contrary in the AVAST privacy policy, you consent during the term of this Agreement and for one (1) year thereafter to (i) AVAST sharing information collected by you during your installation or registration of the Software with AVAST’s distributors and other business partners and (ii) use of such information by AVAST, its distributors and other business partners to present you with information that may be relevant to you, including offers of software, services or other products."

by dnr on 22. September 2013 - 6:20  (110914)

I ended on this site looking for review that might address the fact that, as you mentioned for AVAST, these guys are collecting data on us and passing it around to there friends and [of coarse] making money on it some how. I decided not to stay with AVG because of there personal data collection policies, "email, web sites" and more. That was enough for me. Soooooo...... what to do.

That would be a real help to the masses [like us] if techsupportalert could include in there reviews if the AV software collects personal data and if it does, what data and how much.

by MidnightCowboy on 22. September 2013 - 7:28  (110915)

The majority of software vendors collect user data for either marketing or product improvement purposes. Exactly what they do collect is detailed in their FAQ and EULA which users should read before installing the software. Additional information that may be of concern to some users can be found in their own support forums, and in the case of security software, in the Wilders forum.

Gizmo's Freeware will not be including this type of information in reviews unless there is a major concern about any one product which would likely be removed anyway. MC - Site Manager.

by George.J on 22. September 2013 - 7:40  (110916)

Exactly it's just that these users are too paranoid about privacy, when most of the information collected are non-personally identifiable. Also FAQ section of good software's covers what information they collect.

by George.J on 23. August 2013 - 4:26  (110279)

I wouldn't be surprised since most softwares have EULA along these same lines.

(i) "Sharing information" as in the samples found in individual computers for testing false positives and other information. Using the same to update database signatures etc etc... I think can disable this by deselecting Avast Community Program.

(ii) Mailing you about Avast information, according to your preferences, and finding if you have Chrome installed on your PC, if not recommend the product to you during installation.

Definitely not spyware.

by althu21 on 18. August 2013 - 19:05  (110199)

360 Internet Security 2013.
From more than last 7 years I'm a regular visitor of this site.But this is my first post as yesterday I saw a review on 360 internet security. Then I searched about the software & got interesting results.
Quick installation. Attractive interface. Good scores in antivirus tests, both from PCMag and independent labs. Built-in feedback form for reporting any problems.,2817,2422024,00.asp

by George.J on 19. August 2013 - 2:06  (110202)

Anyone who's looking to download the software can go to the official English website:

by George.J on 19. August 2013 - 1:33  (110201)

Interesting...We've had a thread about it on our forum.

by JediInverse on 26. July 2013 - 8:44  (109625)

BitDefender has recently updated their free Anti-Virus and the new version includes real time protection (about time IMO). As I understand it, the software is based on last years commercial AV product rather than the current release, but I do remember seeing some very good reviews for it at the time. The software itself is light and fast, very simple to use with very few settings or advanced options to play around with, in fact once installed you hardly know it is there. If you're looking for an install and forget AV package this may be the one. Will be really interested to see how you guys rate it against AVAST and the others.

Oh BTW I had to download it from the USA site, the version available on the UK site is still the old software with no real time protection. Just switch the country at the top of the screen to USA and then download the software.

by rfithen on 4. August 2013 - 2:34  (109890)

The antivirus portion seems to work fine; but the program is blocking me from known good sites like: instantbird, portableapps download section, some downloads on sourceforge; etc. ....and when clicking "continue anyway" it does not seem to react properly. just my take.

by MidnightCowboy on 4. August 2013 - 5:35  (109891)

Antivirus programs are designed to protect their users. Within this process there are always likely to be some false positives.

Specific to your experience, I can't comment about Instandbird because I have no knowldge about how they operate but Sourceforge have recently introduced a wrapped installer (like cnet)
which will certainly explain Bitdefenders intervention there.

I always recommend users research what they want to install via Google first in case something is missed by their antivirus, in which case the above links would have provided the information necessary to make an informed decision.

Genuine false positives can and should be reported to Bitdefender for the benefit of other users.

MC - Site Manager.

by AJNorth on 5. September 2013 - 10:27  (110540)

Yes, what a shame that SourceForge decided to add a wrapper to their installers (and they use to be a completely reputable site...).

by Anupam on 26. July 2013 - 8:51  (109626)

The free antivirus from BitDefender with real time protection has been around for quite sometime now. Although it seems good, but earlier, it did not come with much control, which many users saw as a disadvantage. Although, with recent versions, they have made a few changes to the product, as a result of the users feedback. We had a discussion on the product in the Freeware Forum. You can take a look:

by f0xx396 on 25. July 2013 - 16:53  (109600)

Malwarebytes anti malware I think deserves some mention here, granted its not a dedicated antivirus but its malware scanning I feel is on par with Avira.

I use Avast and malwarebytes as both allow for manual updates, a rare feature. This combined feature gives me the good I would have got from avira, but avira got in the way of my gaming. Avast has silent gaming mode feature, allowing my games to move along without interruptions. Avast version 8 is lot more lighter and resource friendly.

by MidnightCowboy on 25. July 2013 - 22:54  (109607)

Malwarebytes is featured on the appropriate pages of this site including these:

As the free version contains no real time protection, it is not suitable for inclusion in this review. MC - Site Manager.

by LynVT (not verified) on 22. July 2013 - 13:15  (109478)

I posted a long time ago trying to find a way to (completely) avoid the (obnoxious) Avira nags and finally gave up and switched to Avast. I'll do a more scientific comparison soon, but pretty sure Avast uses the same amount of memory or less than Avira at least on my old pIII 512MB ram PC with XP pro (which is normally not as bad as you'd think for my needs, unless I have 400 tabs open in Firefox!)

I haven't had any infections with Avast (yet) albeit it has only been a few months, and went many years with zero infections with Avira. Although Avira worked well re protection for me, a couple of less tech-savvy clients DID get a couple of nasty infections (Trojans, one of which took down the whole system) with Avira running (albeit about 2 years ago)- so Avira is certainly not perfect re doing its job, of course, as I guess none of them are. (I have since placed these too-frequently infected clients on Limited User Accounts and so far no infections for them either...)

One thing I really like about Avast is a general software update feature like Secunia, which is a little less obtrusive and more user-friendly than Secunia, at least in my opinion, and combines AV and very important software updating alerts in one package.

by Anupam on 23. July 2013 - 18:10  (109530)

For a long time, I used Avast on my old PC with same config as yours.. P-III with 512 MB RAM. It used to run really light. Firefox did make system a bit slow :)... but was manageable with less tabs.

by LynVT (not verified) on 23. July 2013 - 21:53  (109534)

yeah, something is wrong with my Firefox settings- it is now using 235MB of RAM with only 2 tabs open (and only a few basic addons like ABP)- tried every Mozilla "tip" and also Chrome and not much better, at least a while ago. Anyway, right now AvastSVC.exe is using only 1.8MB and AvastUI.exe is using only 1.7MB of memory. SVC jumps to around 10MB when a new tab is opened, as one might expect, but pretty sure Avira sat at approx. 10-20MB when idle, jumping when opening a tab or file. That said, even 20MB is nothing to most (newer) PCs- Firefox is my problem, the hog...but that's another forum...

by cavehomme on 23. July 2013 - 22:58  (109536)

Probably nothing wrong with your FF settings, simply that FF is a massive resource hog in my experience.

by LynVT (not verified) on 24. July 2013 - 13:20  (109559)

Yeah, I think you're right- can you suggest any alternatives for old PCs? NoScript seems to help, maybe, (and was it more or equally responsible for my zero infections in over 10 years than Avira?) but is kind of a pain and definitely not user-friendly enough for typical users- but it didn't help much. And Chrome was just as bad re hogging RAM with more than a few tabs (I tend to work with many), at least for me. The browser reviews I read gave the least use of RAM resource award to FF. With only a few tabs (less than 10-20) open (typically using FF, Office with big files, PDFXchange, and Thunderbird simultaneously), my PC is just as snappy and useful as much newer ones- so I hate to just trash it for both financial and ecological reasons. I'm changing my browsing habits by grouping tabs by "project" in bookmark folders and keeping only a few open at once- this brings my PC back to "snappy and happy" and is probably a more organized approach to working anyway...

I'm also going to try an SSD and also ReadyBoost- what the heck, why not? I can hear the HD toiling away when my tab number creeps up and FF jumps from RAM to "virtual memory" (i.e. the slow old mechanical HD), so this may solve the problem- will post results in a more appropriate thread..

Anyway, back to the topic, I will reinstall Avira and do a "scientific" test on memory use of Avira vs Avast (turning off one before testing the other of course) as soon as I get a chance...

by cavehomme on 24. July 2013 - 13:29  (109560)

I also changed to a SSD and it's MUCH faster, but I still do get slowdowns with most AV. Just been using Avast for the past 2 weeks and eventually had to remove it because of the impact on browsing speed - all browsers - FF22, IE9 and Seamonkey. I recommend you try Seamonkey as a FF alternative, I find it quicker. It's not as "modern" interface but it's faster and also many of the FF addons work on it, the engine is based on FF.

by Anupam on 24. July 2013 - 13:40  (109561)

The comments are going off-topic, and I will request you gentlemen to take this discussion to the forum please. Any more comments on browsers will be deleted.

by cavehomme on 24. July 2013 - 14:17  (109562)

Huh? Please don't be so trigger-happy, I was mentioning the real impact of Avast upon browsing speed. I concluded that the least impact was with Seamonkey. I have no desire to discuss generic browser topics here, merely relay some of my experience of 20+ years to help others, if they need it.

by Anupam on 24. July 2013 - 18:15  (109568)

My comment was not directed specifically towards yours, but to the whole discussion. Don't take it personally.

Gizmo's Freeware is Recruiting!

Gizmos Needs YouShare your knowledge of free software with millions of Gizmo's readers by joining our editing team.  Details here.