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  • Excellent malicious URL blocking, network protection, outdated software checking, integrated password manager, and comes with a rescue disk.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

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...

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...

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)


It actually depends on your system resources. If you're having enough resources, you won't find any lag. Moreover I believe what you posted here is the idle RAM usage. Try starting a scan, or opening documents, installing executables, copying files, browsing internet, CPU usage etc that can also include in resource consumption.

The real performance of your system often doesn't depend only from some numbers which you can see in Task Manager. That's a general deception...

Personally, although a small subset of users may not feel that an antivirus is suitable for them, I do believe that an antivirus still has a significant role to play in terms of protecting a computer. For a more in-depth explanation of what I believe, and why, please see this section: of my article about How to Stay Safe Online. Thanks.
While you as an experienced user may not need an antivirus, general users still need one. Security is important for them.

I tried the latest version of Avast! (Avast 2015), and didn't like it: it is heavy and cluttered with useless stuff, it's an antivirus that tries to be cool and fashionable with social features, badges, prizes, karma and Facebook, which is not what I need from an antivirus.
At some point my computer was almost stuck: one of the Avast files was using 200+ MB of RAM and growing, and it was using at least 20% of the CPU resoruces, not sure for what reason, because couldn't tell from the user interface and it was unclear how to stop whatever it was doing. It's the kind of situation that makes me remove a software right away, because I don't like when a software does not show clearly what it is doing and ruins the performance of a computer.
Currently I removed Avast and I'm trying Panda (v. 15.0.3).

I have to agree, the new Avast! looks great and all but it just became the new AVG but its resource usage is better than AVG

The process that was causing that usage was probably the new Avast! NG. You can read about it here,

Its sounds good but it takes up to 2GB of my HDD space, I'm also currently trying Panda

The download link for "Panda Cloud Antivirus" is outdated, it's not working. I got it through the official website.

Thank you for pointing this out to me. The link should now be fixed.

If I may put my two cents in, Bitdefender free edition is not a good choice.

You have to download an installer -an offline intaller simply does no exist- and the installation needs several consecutive downloads even after the installation. The first definitions update takes a while and sometimes goes wrong, so the program forces you to start the updating process again. I know this because I tried installing bitdefender on different PCs from friends and relatives, so I can say the process isn't as smooth as you'd want.

The installer does not include an uninstaller, you have to download a third party one if you ever get bored (or annoyed) by Bitdefender. Also, you have 30 days to test the product, after that period you are forced you to create a free BitDefender account or login with facebook or G+ within the app to continue using the product.

IMHO, not the best of approaches.

Agreed with the points. For the same reason, I was not able to install this antivirus on an old computer which is not connected to the internet. I was looking for a lightweight antivirus, and I thought BDAV free would be a good choice. But, lack of offline installer, and creating a free account was what put me off. Even if offline registration was possible with it, like Avast has, I would have given it a try, after connecting the PC to internet for a while. But, given the present situation, gave it a miss. With lack of customization, and these issues, they are really making it hard on themselves for users to be able to accept this.
Thank you UserError and Anupam. I have now added information about the lack of an offline installer and the required registration to the article. Thanks again.
Thank you for letting me know of your experiences with this product. I will keep this in mind. Also, what are others experiences with this product. Have you run into as many problems with it as UserError? Thanks.
360TS now has it's own new website, totally for the product:
Wonder if this is the prelude to 360IS being discontinued? MC - Site Manager.
Version 5.2 beta is now released. I don't understand why they are trying to make the UI similar to that of Baidu's.
There appears to be some sort of agenda in play here. No doubt all will be revealed in time. Problem is the balance of opinion is still well in favor of IS over TS. MC - Site Manager.
That would make me sad :( Anyway it's still getting product updates, although minor ones. 360 Internet Security'D' has been released. Currently the IS version is more stable than the TS version.

I thought you should know that it has gone worse, now Comodo SecureDNS completely blocks access to Qihoo's English website:


It's worth noting that this didn't happen before, it was only blocking the download.

Thank you for keeping me up-to-date. I have been keeping an eye on it, and I believe the number of false positives it gives is too large. I have therefore updated my information for this article. I now recommend that users untick the option to Enable Comodo Secure DNS during installation. Thank you very much for bringing this to my attention.

it may not be a false positive. there are many corporations (one of which i worked for) that have proprietary secrets and/or negotiations ongoing for business deals. our servers were repeatedly hacked by hackers located in china. how they accessed our systems led to the banning of communist/state owned/chinese software for all employees in sensitive areas. i guess it make sense(?), i doubt the u.s. military used soviet cloud based antivirus software to secure their systems during the cold war, lol. perhaps comodo is aware of this building tension/caution within governmental and business environments.

File Detection Tests Real World Protection Tests Avast does extremely poor in File detection tests and came last. Excellent results for Avira (Pro) and Qihoo. Panda does a fair job.
As per my methodology I only use the results from Real World Protection Tests. In those Avast has consistently been doing quite well. The issue with File Detection Tests is that they really only test what has become just one part of the job of an antivirus. These days what matters is how all of the protection layers add together to protect a system. Thus, focusing on just one, such as File Detection, doesn't really give a good picture of the protection capabilities. That is why I leave out any descriptions of file detection statistics, even though historically that used to be what was most important in terms of protection. Let me know if you have any questions, or concerns, about this methodology. I am always looking for issues with it so that this advice can be improved. Thank you.
Thanks but Avast faired poorly in file detection mainly because of the 140 false positives!! :| Anyway these results change from time to time.
I have thought about including False Positive information, but still have to find some tests which I believe are decidedly real-world enough in terms of how likely users are to actually run across false positives of the type they are being tested against. I will look into including information like this in the next rewrite, assuming I can find some tests I am happy with. Thank you.

I tried to download Qihoo's 360 Total Security to test it but I got this warning message from Comodo SecureDNS:

Any idea what's this all about?

That is a false positive from Comodo SecureDNS. I have reported it to them as a false positive. Hopefully the detection will be removed in the next few days. If detection is not removed within 5 days please let me know. If it takes that long to remove a false detection I would rather advise people to not use the SecureDNS, but disable that particular feature. Thus, please keep me updated about this detection. Thank you.

Will do and you're welcomed.

I am still curious as to why "MSE" isn't included in that list? It remains to this day one of my favorites and from my experience it proved to be an excellent set-and-forget free antivirus.

Also, could you state which antivirus require yearly (free) registration (such as Avast) in order to continue to function? Because the "set-and-forget" is an important factor for me since I tend to install AV on several PCs.

Thank you for reminding me of MSE. I have now added it to the article as one of the AV's I looked into, but which have protection scores which are too low for me to recommend. The problem with MSE is that although it is very easy to use, the protection rating for MSE is lower than the vast majority of tested AV's. Thus, I would highly advise against using MSE. It used to be good, but has now fallen very far behind the rest in terms of true protection. Some tests even use it as the baseline against which all others are compared.

Thanks for the clarifying that, it's good to know.

What about my second question? It's really crucial for my choice process.

"Also, could you state which antivirus require yearly (free) registration (such as Avast) in order to continue to function? Because the "set-and-forget" is an important factor for me since I tend to install AV on several PCs."