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...

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...

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...

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...

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...

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)


My pleasure, Chiron, and welcome aboard!


Thank you. I am new to this article. However, I am not new to techsupportalert. I have published 13 other security and privacy articles on this website. In case you are interested in checking these out, they have been added to the bookmarks of my profile. Thank you.
Hello, my name is Chiron and I am the new editor for this article. I have just made a small change to the article (removing MSE due to very bad protection results). However, many more changes are coming once I have improved upon the new procedure I have come up with for comparing antivirus products. My aim is to differentiate between those products which just have good detection scores versus those which may have lower detection scores, but due to other technology can actually protect you better. Keep an eye on this article over the next few weeks for these improvements. Thanks.

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.