Best Free Antivirus Software

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To begin with let me say this: there is no best antivirus out there. Why do I say this? Any product that you take will behave differently against various virus samples since the AV engines and other components incorporated in them are of different technologies.

While one product might have higher detection ratio, another might have better malicious URL blocking or virtualization techniques, yet another might have lesser impact on system performance and so on.

Read more about Antivirus Engine and other related details at the end of this article.


Rated Products

Kaspersky Free Antivirus/ Kaspersky Security Cloud  

The paid security giant forays into free category and outsmarts its rivals

Our Rating: 
License: Free (Limited features)
  • Similar signatures & cloud features as its paid counterparts
  • Performance impact is decent on higher end systems
  • Strong behavioral blocker
  • Attractive GUI with no ads
  • Top-notch detection and always up-to-date
  • Thorough malware removal and disinfection process
  • Privacy policy (complies with GDPR)
  • Default settings cover most users
  • Bundles with Kaspersky VPN (can be uninstalled)
  • Fairly good web protection
  • Powerful exclusion settings (even for specific modules)
  • Extensive scan logs
  • Protection settings are locked with presets in Kaspersky Free Antivirus (KFA) [is available in Kaspersky Security Cloud]
  • Long but thorough system scans
  • Performance hit becomes worse on lower end systems
  • Slow update installation
Read full review...

Avast Free Antivirus  

The only antivirus with a fully customizable installer and selection of user preference components.

Our Rating: 
License: Free (Limited features)
  • Extremely light on the system with a modern and clean UI
  • The only antivirus with a fully customizable installer, selection of user preference components
  • Works best in hardened or lock-down mode, which blocks all unknown programs (medium-expert users only)
  • Top notch detection capability, many secondary components to offer variety to a wholesome software
  • Excellent malicious URL blocking, network protection, outdated software checking, integrated password manager, and comes with a rescue disk.
  • Deep screen technology that includes Sandbox and Safe machine components for protection
  • Bloated default setup, some ads and pop'ups
  • Account creation for further protection after a month
  • Lack of an anti-ransomware module, and Deepscreen disabled by default
  • Cloud reputation, Malware signatures and HIPS module needs improvement
  • Offers Google Chrome and various bloated secondary components during install [Choose custom install]
Read full review...

Comodo Internet Security Premium  

Provides a multi-layered protection scheme with HIPS, sandbox, antivirus and firewall.

Our Rating: 
License: Free (Limited features)
  • Feature-rich with lots of options for customization along with setting tolerance against prompts
  • Tweaked settings gives the best 0-day protection among the pack
  • Multi-layered protection scheme with HIPS, Sandbox, Antivirus and Firewall
  • Industry grade firewall with options for learning and behavioural blocker
  • Low on resources with various graphical skins available and a clean user interface
  • Painful for beginners to use it, not very newbie friendly 
  • Av-module is a bit weak especially the signature based detection
  • Auto-sandboxing happens for various legitimate files, troubles with FPS games
  • Too many tweaks needed for better protection
  • Buggy software and updates are released slow.
  • Chromodo browser, Yahoo search engine, custom DNS and Geek Buddy offered during default install. [Click customize installation during install]
Read full review...

Qihoo 360 Total Security  

This free antivirus is better than most commercial ones.

Our Rating: 
License: Free
  • Totally free, light on resources, extremely fast scan times and pre-configuration protection modes
  • Smooth running installer with no adware, pleasing UI and comes with many themes
  • Fast updates/fixes and excellent customer service with immediate replies
  • Great signatures with multiple engines and in-house cloud protection
  • Web protection addon, browsing locking, webcam, sandbox and usb protection modules
  • Online shopping protection, malicious URL protection and network threat blocking
  • Includes Glasswire Firewall and Windows patch-up components
  • Great detection rates, with very high zero day protection
  • Speedup and clean-up tools might not be for everyone (not present in Essentials version)
  • Bitdefender or Avira engines not enabled by default
  • Might encounter few false positives
  • PUP [Potentially Unwanted Programs] detection needs to improve
Read full review...

Avira Free Antivirus  

A free antivirus with high quality signatures, very fast updates and less false positives.

Our Rating: 
License: Free (Private/Educational use)
  • Pretty light on the system and runs smooth without system slow-downs
  • Clean ad-free GUI, Ad-free installer, No pop-ups or ads
  • High quality signatures, very fast updates, excellent detection on non-zero day threats
  • Deep file scans with very less false positives
  • Avira Protection Cloud makes for an excellent cloud engine
  • Browser safety Add-ons available for major browsers
  • Zero day protection (heuristic & behavioural shield) is very weak. 
  • Ineffective Browser launcher which is a memory hog (can be uninstalled)
  • Painful removal for detected files. Repeated scans from Luke Filewalker increases CPU & RAM usage. 
  • Multiple file exceptions needs to be added (real-time and on-demand)
  • No firewall/sandboxing/web shield technologies
Read full review...

Panda Free Antivirus  

Gives you antivirus protection with low memory and CPU usage, and collective intelligence cloud security.

Our Rating: 
License: Free (Private/Educational use)
  • Low memory & CPU usage thanks to cloud protection
  • Tiled UI with customizable interface and nicely rendered Settings interface
  • Collective intelligence cloud security - Downloading virus definitions is history
  • Good detection rates and behavioural analysis program
  • Fairly good web protection and hardware resource handling
  • Dependant on internet connection leading to weaker offline protection
  • Slow scanning speed, no fingerprinting (successive re-testing same files) and at times issues with virus removal
  • Not really light, performance impact in web browsing, installation and copying
  • Certain false positives despite the information available at cloud
  • Watch out for Panda security toolbar during install
Read full review...

Honorable Mention


Related Products and Links

How to make an antivirus engine

Other Articles By Chiron

Related Free Antivirus Software Articles

Related Security Articles


Antivirus Engine

It is used for Real Time malware protection of files and is the core component to scan data on your PC for detecting and removing malware from hard disk, memory, boot sectors, network drives, removable disks, or from external network traffic (internet).

  • How does an antivirus detect malware:

Firstly you got the signature-based detection which contains an offline database of known patterns of malware downloaded from the internet which can identify specific malware codes or family of malware. Then you have heuristic based detection that identifies pieces of code that are unlikely to be found in legitimate programs and hence is prone to false positives depending on the sensitivity of heuristics. Virtualization and sandboxing unpacks or executes unknown programs in an isolated secure environment so that their behaviour can be analysed and scanned using the antivirus engine. The latest one is cloud based detection that requires a reliable internet connection and sends the suspicious scanned file over the internet and the analysis is done by the vendors' machine running the cloud engine.

  • Scanning for viruses:

Most antiviruses include these basic scan types: On-demand scan/manual scan is initiated by the user from right click context menu or from within the software. On-access scan is initiated when the resource is being accessed like running an executable, copying files from external drives etc. Scheduled scan periodically ensures that the system is free from malware by setting the time and frequency for scanning. Startup scan/quick scan checks most important locations like running processes, startup items, system memory and services, boot sectors and so on.

To be Continued in the next update....... Firewall, Proactive protection, Web protection components and more.



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

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Please rate this article: 

Your rating: None
Average: 4.3 (2219 votes)


Protection level is not just about the percentage of samples that an antivirus can identify, other features are added to a paid antivirus solution to keep you safer. Although a home user doesn't need all those "extra's", except for large business where data security is of utmost concern.
Thanks for pointing out the confusing wording. I have now updated it to read that "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". If anyone can show that the level of protection is absolutely identical then I can use the results for the paid version. This can be done for Comodo Antivirus. However, until someone can show me that the free version of Bitdefender offers exactly the same level of protection, not just the same components, I cannot use those results. I hope that makes sense. Thanks.

What I am trying to say is........

For example - AVG free autoupdate is not often like paid. This too can affect the protection. No Webshield/Online shield in free like paid.

For example - VB RAP test - You can see there is difference in protection by Avira free & paid. Avira free doesn't provide Webshield like paid. Avira Browser Security in free is not like Webshield in paid, there is no HTTP scanning in free like paid. Avira too doesn't autoupdate often like paid.

I know there are tests available for these AVs & that can be put in the review. But the same thing can be said about these free AVs i.e protection not identical with paid. You didn't mention this for these AVs but you mention this for BD free, that kind of looks unfair to BD free.

About BD free - I am little busy, when I will be little free, I will try to scan Wilders links & provide you the facts/confirmation about BD features/protection by BD staff. If you have time, you too try to do so.

I have tested & compared BD free with paid & other free AVs too & I find it an excellent free AV especially for average users. I find it better than all the free AVs mentioned here in terms of protection & everything for average users, not including CIS as CIS is way better than all the AVs mentioned here & recommended for advanced-intermediate users. I know my tests doesn't count, just sharing my test experience.

The reason I did not mention that the protection offered was not the same for many of the other Free AV's is because the Free versions were tested by the testing organizations I used for this analysis. Thus, there was no need to compare the Free to the paid versions. I could just look at how the free versions compared. However, I cannot do this for BitDefender because the Free version has not been tested by those tests. The only reason I mentioned it is because if I didn't many users may mistakenly think I could use the results for the Paid version. Thus, this is just an explanation to prevent confusion about why this particular methodology was chosen. Also, I have no problems with Bitdefender Free. It does seem like a very good product. If I didn't think it was I would have removed it from the review altogether. It's just that I'm trying to keep this review more factual. Thus, as I have no definitive data on how it compares to the others (using the real-world tests I referenced) I cannot recommend it over them. I'm sorry if my wording suggested otherwise. Thank you.

You have mentioned in the review that it is not tested yet by any testing organization so you cannot recommend it above others. I totally agree here.

But I do think "protection level has not been shown identical with paid" is not required.

Collect facts/info about BD free & put it in the review would be better.

I am defending BD free coz..........
Before using it, I read all the posts i.e above 100 pages in the Wilders links that I have mentioned in one of my previous post so I know the facts/info about BD free. I can mention here but that would not be enough so I asked you to go through the Wilders thread & get all the facts/info.

Thats all I have to say about BD free topic.

I know you will do an excellent job maintaining this section as I know you very well from Comodo forum. I dont know if you know me but I too am at Comodo forum with the same ID i.e naren.

In the review I mention that the only reason I even bothered to say that the protection level has not been shown to be identical with the paid is that I cannot use the results for the paid in my analysis. I think that makes sense to put that there. Without it many users would accidentally compare it with the results for the paid version. As mentioned previously, I do believe that Bitdefender Free is a very good product. If I did not believe that I would have removed it from this review. I did that with MSE, which was previously recommended. As for putting in additional information about Bitdefender Free, please provide me with your recommendations about the type of information which could be added. This sort of information will likely be very helpful for my next re-write. I did assume that you were the same naren from the Comodo forums, although I was not certain until you just confirmed it. I do appreciate your comments, and I also hope you are beginning to better understand my position. Comparing AV products is a very difficult task, and there is no one perfect approach. Thank you.


I gathered few posts by Bitdefender staff about Bitdefender Free AV at Wilders.
Hope you will take time & check the posts.

Bitdefender Free AV
Posts by Bitdefender staff about Bitdefender Free AV.

Posts - Pages
54, 66 - 3
147 - 6
327, 333 - 14
381 - 16
471 - 19
545 - 22
551, 564 - 23
603, 605 - 25
683 - 28
758, 773 - 31
910 - 37
942, 943, 945 - 38
993 - 40
1491 - 60
1592 - 64
1808 - 73
1886, 1888 - 76
2190 - 88
2226 - 90

Thank you. I will update the Bitdefender information during my next rewrite.
For me, no matter who says what about anything, the bottom line will only be evident when the free version is tested alongside the paid as with AVG in the AV-Test results. MC - Site Manager.

"but I do with they made the process simpler." s/with/wish

Is comodo suitable for running on an htpc ie I don't mind getting popups to configure initially but don't want to be getting them constantly while trying to watch shows etc.

From my experience you won't get too many popups at all, even initially. It's really much, much, much quieter than it was even a few years ago. I think you'll likely find it to be a good match. Give it a try and let me know what you think. If you have any questions about Comodo Firewall feel free to ask. Thanks.
Agree with the top pick here...Although I'd say it's more leaned towards intermediate->advanced users. I'd suggest newbie's to stay away from Comodo. Other than that, the new Comodo 7 antivirus is smooth and amazing. You've the firewall defense (which is not included in most antiviruses), sandboxing feature (700% faster) and lot more features in the new version.

Isn't v7 in beta still?

I usually visit Softpedia to download softwares and like their caption Updated One Minute Ago, they are very fast in updating their software list. Here's Comodo Antivirus 7 at Softpedia:
Thanks for pointing this out. I would advise that users download and install V7 rather than V6. It is the newer version, and appears just as stable. However, until the main Comodo Antivirus page updates such that it is V7 which is downloaded, I will keep the version listed as V6.x. This way it will not confuse users who are already running it, and try to see if there are any updates. Thanks.
No it is not. The final version has been released to the forum, although those running V6 will not yet receive an automatic update. Also, I'm not sure whether the main download page directs users to V7 or V6. Regardless, the release topic on the Comodo forums will allow users to download V7 final. Thanks.

Not directed at Chiron specifically but is a direct link to the v7 download or topic to much to ask for? Normal download process gives me V6 and I'd like to avoid having to hunt through their forum for it.

Do you know why it's 220MB? I know software keeps getting bigger and bigger, but is there something in particular about this one that makes it perhaps the largest?

Unless I'm mistaken, the main installer contains the files for both the x86 and the x64 versions. During installation it will automatically install the correct files. It also contains the additional software, which I warn about in my review. I believe some 3rd party sources may remove those extra software. I hope this is helpful. Thanks.
Comodo Antivirus is just 100MB download: The Internet Security version has firewall and such, which most basic antiviruses doesn't have.

If you follow Chiron's v7 download link you'll see the new version is 220mb.

Not sure what's happening there... Although they have given three different links, all link to the same setup file [220MB download]. I mean why should IS, Antivirus and Firewall have the same setup size. Softpedia link points to Comodo Antivirus 7.0 and is a 100MB download [x64 version]. Probably the link given in the forum is just one setup file. Edit: The x86 version is 220MB download while x64 version is 100MB. [puzzled].

Although all listed their size as 220m I did notice all three had different md5sum's...can you post the direct softpedia link?

x86 version is a 220MB download while x64 version is 100MB. [Link removed - direct download links are not permitted. Please use the site PM system for this]

Thanks Chiron, I'm running v6 CIS and as you say it isn't reporting any available updates.

I had a look around Comodo and FileHippo etc (the screenshots on FileHippo look like v5?) and the Comodo download appears to be v6 still, so I thought I'd ask here.


I thought about this some more, and what I have ended up doing is I edited the information so it now reads V6.x. This way there will be no confusion. Once V7 is made available through the auto-updater I will update this to refer to V7.x. Thanks for pointing this out. Let me know if you see any other issues with this review. Thank you.

The 'Sandboxing' feature in Avast has been removed.

I was not aware of this. However, it looks like this was removed and the DeepScreen feature was added. I will update this review accordingly. Thank you very much for bringing this to my attention.