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  • Excellent malicious URL blocking, network protection, outdated software checking, integrated password manager, and comes with a rescue disk.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

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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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Average: 4.3 (2219 votes)


norton dns says that link is a malicious web site.

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

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

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

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

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

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

Yes, MSE does slow down the computer a bit, I have observed that too.. specially in opening the folders with exes, and in other areas too. About you facing other problems, I think you should re-install it once again. MSE updates via Windows Updates without any problems, and the scan time should also hold. However, I have seen that MSE updates occur very very slowly sometimes, like painfully slow.

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

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

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

Would Avast or Antivir be better for computer performance?

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

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

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

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

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

Let me Share with you the detailed results:

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

Here are the results:

January 2013:

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

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

February 2013:

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

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

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

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

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

Unfortunately though it is necessary to compare apples with apples and not the orchard owner's interpretation of what came off the trees. In this respect AV-Test clearly states that: Protection against 0-day malware attacks, inclusive of web and e-mail threats (Real-World Testing) was 84% and 90% for Jan/Feb when the industry average is 95%. Also: False blockages of certain actions carried out whilst installing and using legitimate software scored 5 when the industry average is only 1. False positive detections were also more than three times the industry average. On this basis, the ZoneAalrm test results (which is also free) are higher: Of course you can argue all day about the relevance of these tests (and indeed others) to average home users but that is not the point in question here. Also, when I look at these things I do not perform the exercise alone. In addition to my own installation I impose the software on a range of folks including friends, neighbors and ex customers who like to feel they are contributing to a service. The overwhelming feedback I get regarding CIS is how difficult it is to understand and configure. Admittedly this centers mainly on settings above the default configuration but the fact these are there suggests to any right minded person that the protection level must be greater when these are employed, otherwise why have them? This is when the majority of users get lost, and making wrong choices has the potential to damage their system or protection level thereof.

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

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

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

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

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

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

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

Well, since you use a beta version, you cannot really complain about it, can you? :). Beta versions are for testing purposes. I have been using Avast 8 stable version, and I dont have any problems. Also, the releases generally take some time to stabilize because of different issues. So, it's best to wait for a while, and look at their forum to see if any issues are there. If there are not, then you can install the version, otherwise stick to the older version until the issues are resolved. A new version of Avast 8 was out recently, but I have not updated yet for that reason.

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

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

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

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

will stick with Zone alarm free antivirus and firewall

Thanks all have got Avast 8 working fine with malwarebytes free and zone alarm firewall

Good to know :)

I've been getting some crazy errors with Avast since I installed it on my new rig. Every few days, the free version upgrades itself to the pro version and subsequently demands me to renew my subscription. It's a problem that I saw several other users were having on the forums as well, and Avast has yet to issue any kind of statement or help for the problem. Just thought this should be mentioned for potential users.

Any thoughts on Bitdefender Free? Seems a bit light on options but detection rates sound excellent.

Avira Free A/V has been updated to version (dated 2013.03.19, but rolled-out today), weighing-in at 108 MB for the off-line executable and 2 MB for the on-line installation manager. It is a cumulative roll-up with additional enhancements and bug fixes; a restart will be required for updating existing installations. The full changelog at (of particular note is "The second highlight is the preparation of Avira Free Antivirus for Windows 8 certification.").

Avira's downloads are at . A PDF of the User Manual is also available for download.