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

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Quick Selection Guide

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:

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.

Comodo Antivirus

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.

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

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.

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.

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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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.

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

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

There are several threads about the Nuqel worm in the Avast! forum going back to 2010 but the information they contain is not that comprehensive. Nevertheless it appears this malware is still being missed by Avast! Possibly this is because the code of the worm is being constantly changed into new "variants". One recommendation is to consider an additional program that protects specifically against malware that uses USB devices to spread. MD - Site Manager.

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

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

Your welcome. :) There are comments about it here: There are also recommendations for it in other places, including the Avast! forum. As ever, this will be another tool to help in the battle against Windows malware in the knowledge that no one single product ever can. MC Site Manager.

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

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

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

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

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

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


In your review you say about Panda,

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

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

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

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

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

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

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

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

Hiya mike I read your thread with interest.

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

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

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

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

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


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

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

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

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



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

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

Please suggest a good AV which is compatible with windows 8.1

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

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.

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.

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.

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.

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.

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.


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.

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.

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.

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) -- .