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 Anonymous on 3. March 2009 - 15:23  (17128)

thanks for the info. that's good to know.

by MidnightCowboy on 2. March 2009 - 16:50  (17048)

No doubt we shall see you registering then now so that you can discuss issues with us in the forum out in the open instead of hiding behind anonymity?

VB is well known not to be the most reliable of testing establishments. The following is extracted from their reply to F-Secure.

"After some investigation, we discovered that the product submitted for the test did not include the latest updates available at the submission deadline. After retesting with these updates in place, F-Secure comfortably detected everything on the WildList, and would easily have qualified for the VB100 award had the correct data been supplied. Their customers, with the benefit of automatic updates, would certainly have been protected by this solid and reliable product."

What this demonstrates mostly is the importance of updates. It's easy to stuff your product with updates and then submit it for testing. What's not so easy is to have it checked by Av Comparatives who do retrospective as well as on demand testing. The inference here of course is that even if the detection rates are high, but the updates infrequent then the overall performance is degraded.

I never have expressed any "expertise" in any field (except psychology) and what I said about Rising was.....
"but does it all work? Detection rate tests can be pretty ambiguous at the best of times (especially VB) but if this performs half as well as it looks and navigates, for the average user like me it has be a top consideration. When and if I get enough time to make a proper evaluation I'll write more across in the forum."

I guess from your tone that you might be an Avast! user which is and always has been a solid product although recent issues (from their forum) would indicate that quite a number of users are experiencing difficulties. Writing stable and efficient security software is becoming more complex and more difficult, as is the use of it for many people. There are certainly issues at the present time that will dissuade some from trying Rising, but on the other hand Google would not have gone down this road in China without much thought and deliberation. I am maintaining this software permanently on one machine and will still report on how I feel about it. How others seek to use this information and/or access the reliability of it is of course up to them.

by Anonymous on 4. March 2009 - 9:56  (17183)

As usual, wrong again!
I am Neither an avast, nor an AVIRA AntiVir user.
Above all, I am NOT a Rising user!
I'm a Software Security (Ph.D. level) Researcher,
and I cannot stand 'geniuses',like you,
spreading LIES to Average users!
I am Not here to promote any specific software!
Reading your posts, MidNightCowboy,
makes me wonder about your Irresponsible character!
Average users,please, do NOT take for granted
anything you read here!
There are many posters, here,
(I don't want to characterize them...)
who play the Software Security 'expert'/'guru'/'genius'.
Do NOT believe them, if you love your PCs!
Stay with what the Editors suggest!

by Anonymous on 4. March 2009 - 13:21  (17193)

gee, Anonymous, for a Ph.D.-level researcher you're really managing to avoid the provision of any actual evidence for your claims against Midnight Cowboy!

by MidnightCowboy on 5. March 2009 - 20:24  (17290)

Yes - interesting too that you can 'research' anything that you haven't used?

by Anonymous on 4. March 2009 - 21:14  (17226)

I gave some evidence, but you didn't notice.

BTW, what kind of evidence has MidNightCowboy offered you
when he wrote about the effectiveness of Rising AV Free?

Want some more evidence?

If you want to believe untrustworthy 'experts', be my guest...
However, many average users prefer to Stay Away from Charlatans!!!

Over & Out!

by MidnightCowboy on 5. March 2009 - 20:30  (17291)

If we refuse to consider software because of an 'inferred' link to corruption or 'dirty tricks' then many of us would end up looking at a blank screen!

by Anonymous on 5. March 2009 - 21:27  (17294)

Stop promoting CRAP-WARE like Rising AV Free!
You deliberately Ignore well-established companies
with Long Tradition in Security software,
and you propagandize Low-effectiveness
(not to say of inferior quality) firms!
Are you so Ignorant/Irresponsible that you advertise Crapware
-OR- are you getting paid for it?

You did the same with Poor-effectiveness/low protection
Firewalls against Comodo and Online Armor Free!

Then, you did the same by promoting Rising AV Free
over Avira Free and avast! free.

Sorry, but you are NOT a Trustworthy poster!
We cannot follow your postings as suggestions/reviews!

You are NOT someone we can Trust, Mr. MIDNIGHTCOWBOY.
Write/promote whatever you want...
We canNot follow/share your views!

by MidnightCowboy on 7. March 2009 - 1:40  (17365)

Since writing my first piece I've been appointed as Category Editor for HIPS so any trialing of AV programs I shall leave in the more than capable hands of JonathonT as I need to concentrate on my own category.

I'm repeating the same extract again below from my original statement because it appears that you have either missed the point or even missed "it" altogether.

"but does it all work? Detection rate tests can be pretty ambiguous at the best of times (especially VB) but if this performs half as well as it looks and navigates, for the average user like me it has be a top consideration. When and if I get enough time to make a proper evaluation I'll write more across in the forum."

As you can plainly see, the statement clearly questions the capabilities of Rising and then uses the words "if" and "consideration". This is not remotely a promotion.

As software consumers we all have preferences of course but as Category Editors we also have a duty to write and report about what people are using. Like it or not 1000's of people are taking up Rising AV, especially since Google began including it with their Google Pack in China. My own "trial" of Rising has now gone from my PC and been replaced with Avast! because that's now one thing less for me to worry about as I begin researching some alternative suggestions for HIPS programs. If in time it turns out that Rising AV is inferior then I guess we will continue to write about it because this is the best way to encourage the producers to make improvements. Currently I'm looking at DSA (Dynamic Security Agent) and DriveSentry - do you have any thoughts on these?

by Anonymous on 8. March 2009 - 23:47  (17445)

DSA? Still trying crap-ware, ah?
Dynamic Security Agent FREE: 62% POOR

Keep Mis-Informing users and
promoting Apps users should stay away from it!

A friend of mine reads a lot your postings!
He knows that when you write about a specific software,
he needs to avoid it!
It happened with Netveda, Rising, DSA etc.

It is very disappointing that they appointed you
HIPS-Category Editor, because you have you are NOT
an IT professional!
You have neither Studies nor Professional Certification
related to the field!
You are just a user; not an expert!
Therefore, what you write/suggest/recommend LACK any VALIDITY!

by kendall.a on 23. February 2009 - 18:14  (16675)

I hate to disagree with our fabulous editor, but I just wanted to share my recent experience with Avira.

I used Avira Free for quite some time. I really liked it. I recently paid for the Premium version 1) to add the spyware function; and 2) to show my appreciation for the free version and honor their work.

First of all, I had to totally uninstall the free version AND use their registry tool to delete all the registry entries before installing the Premium version. After installation, it worked fine for a couple weeks. But, then it began locking up and causing blue screens. At first, it was a srframe.mmf file. After putting that file in as an exception, Avira found another file to lock up on.

I spent the better part of 2 weeks trying to fix it. At first, I was told it was competing antispyware programs, and not upgrading to IE7 or SP3. Then, I needed to run System File Checker (I had major issues with that.) I tried running the "modify program" within Control Panel, to no avail.

Ultimately, I gave up on Avira, uninstalled it and installed Avast. Avast installed easily and quickly. I ran my first full, thorough scan (and update) with absolutely no problem. It's been running now for a couple days with no problems at all. My only problem with the free version of Avast is that you cannot schedule scans.

For those of you interested in my trials with Avira, you can read all about it at:

by Anonymous on 23. February 2009 - 16:48  (16673)

Okay, but what if I want to avoid all of this and actually buy a low-cost (is there such a thing) reliable product that will do it all? Which should I choose?

by louis058 on 25. February 2009 - 18:05  (16796)

though i much prefer free antivirus and antispyware like the other person but if you really want a paid solution, i suggest either Avira Premium or Kaspersky, or Norton 360 if you want something that isn't intrusive, as in it conducts scans and updates in the background, so it would do all those things an antivirus does but never asks you to do anything, even the HIPS is automated i think, BUT, its detection rates aren't as high as Avira or Kaspersky

by Anonymous on 24. February 2009 - 21:38  (16748)

There is no one product that does it all. I firmly believe that layered freeware is FAR superior to all in one products like Norton and McAfee. We use McAfee enterprise at work and I CONSTANTLY use Malwarebytes and Superantispyware to clean infected machines. Avira is an excellent product. If you want to pay look into NOD32 or one of the other highly rated STAND ALONE AV products and avoid suites like the plague.


by MidnightCowboy on 28. February 2009 - 0:35  (16901)

Great! Another exponent of the "layered solution"! Please register and come on over to the new forum so us guys can give the 'suite bangers' a run for their money!

by u-ultima on 23. February 2009 - 9:10  (16636)

what would be the best on demand scanner to be run with avira anti virus

by woodshed on 23. February 2009 - 12:42  (16651)

On the 22nd I asked had anyone tried PC Tools Internet suite well today I have removed it locked the whole computer.
Now I think I will stay with Avira

by davy on 23. February 2009 - 12:16  (16649)

i agree with anupam,you can get what you need from this website.davy

by Anupam on 23. February 2009 - 12:11  (16648)

Why do you want an on-demand scanner when Avira is there? Avira itself is a good antivirus with built-in scanner.
If you are looking for anti-spywares in addition to Avira, then use MalwareBytes Antimalware and SuperAntiSpyware.

Anupam Shriwatri, India

by Anonymous on 21. February 2009 - 21:29  (16524)

Does the free version of Avira have a daily nag screen to buy the pro version? I read that it does on Snapfiles. If that is the case, Rising seems like a better deal as it scans for spyware also. I've read AVG is not as good as it was.

by Rizar on 22. February 2009 - 17:21  (16582)

It is a general use nag screen during updates only for all kinds of information, updates, etc. Sometimes for their Premium version. But the article right above has a link to instructions to disable them completely, and you can even disable the splash screen. It also has invisible modes for certain scheduled tasks.

by Anupam on 22. February 2009 - 11:10  (16563)

Yes, Avira has a nag screen, and its there when u update the definitions. But, Avira being such a good antivirus, i think the nag screen shouldnt be much of a problem. Also, on this topic, or somewhere on this site, there is a workaround to turn off the nag screen.

Anupam Shriwatri, India

by woodshed on 22. February 2009 - 10:48  (16561)

Anyone tried PC tools Internet Security Suite yet? Ive just picked up for free at For-Free-On internet.

by Anonymous on 20. February 2009 - 18:55  (16433)

yesterday uninstalled avira antivir in favor of CIS with the antivirus enabled. today ran a AV scan and found a total of 18 threats. HEUR.PCK.MEW was reported 16 times, HEUR.PACKED.UNKOWN 1 time, and HEUR.PCK.PE.CRYPTOR 1 time. anyone else have similar results? false positives?

by Anonymous on 21. February 2009 - 12:38  (16494)

These are heuristic detections not guaranteed "signature" hits. Did you leave the default heuristic setting on "low"? Anyway, with Comodo still giving a multitude of problems (see their forum) why change from Avira which has the highest detection rate? With Avast 4.8 also giving some problems and AVG just not up to scratch if you really wanted a change why not try Rising. Its detection rate is still not up with Avira but its far better than Comodo and as a package its also far more complete. Also uses the same design architecture as Avira. Comodo promises much and has a loyal following but in reality their deliverance never matches the hype except for the firewall although this too now seems to generate system problems for many users. I know that this will seem like a real pain but my opinion is that ANY of these complex applications need to have Windows reinstalled first so that they enter a truly clean environment and do not inherit any existing system problems.

by Anupam on 21. February 2009 - 18:04  (16515)

I have been using Avast 4.8 with absolutely no problems at all. What problems are you talking about? I think Avira and Avast are the best of the lot. Stick with either of the two.

Anupam Shriwatri, India

by MidnightCowboy on 28. February 2009 - 0:53  (16903)

You only have to look on their forum first page about 4.8 web guard. So far over 600 reads and 40 replies - and this is just one topic! OK, so some of these are compatibility issues notably with CFP3 and Threatfire, but as Avast! is (I think) the biggest AV vendor why do it's customers have to accept a product that cannot or will not work with other class leading applications?

by Anonymous on 21. February 2009 - 15:08  (16503)

i did change the heuristic scanning level to high. i might try avast or just go back to avira. thank all of you for your comments and suggestions.

by JonathanT on 21. February 2009 - 2:45  (16467)

You could upload the files to VirusTotal.

And maybe also scan with Superantispyware free and Malwarebytes Antimalware free.

by Anupam on 20. February 2009 - 20:35  (16442)

False positives or not, will depend on what the filenames were on which these threats were detected. Can you tell the filenames?

Anupam Shriwatri, India

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