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  • Excellent malicious URL blocking, network protection, outdated software checking, integrated password manager, and comes with a rescue disk.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


I am running Window 7 on some of my machines. Obviously I only want to use free alternatives at this time since my main OSs are Windows 8.1 and Linux. I found that Defender is still updated on 7 but it is not an Antivirus solution. Antivirus is still needed. As of May of 2020 I found that Avast has added quite a few nag screens as well as making my 7 machine take an extra 3 to 4 minutes to boot up. I will update if I find an alternate program that is more friendly for Win 7.

I decided on Sophos Home. Sophos used to be a Enterprise only Antivirus but you can now use a free home version. You do have to manage it online but it is light on resources from what I've seen, it works on Windows 7, and I have not seen a better alternative. I am still open to suggestions.

Qihoo 360 installed a toolbar and a shopping extension in my Chrome browser. Best avoid it. I'm using Windows 10.

I'm not sure why everyone else should avoid this because you install stuff you haven't checked first.
This add-on is part of their suite and also available separately for anyone who wants it.

We even list an advisory about this in our own product details but I guess you didn't read that either. MC - Site Manager.

Update: Editors new pick for Best Free Antivirus - Kaspersky Free Antivirus/Kaspersky Security Cloud.

Most improved products of 2018: Forticlient, Windows Defender & Tencent PC Manager. The first two has a real shot to be in top five this time.  



I tried using BitDefender, another highly recommended program by It kept causing Thunderbird email to hang, with the "not responding" message. Every time I sent an email, it would stall for 2-3 minutes.

Try to add thunderbird to exclusion list.

Maybe Qihoo 360 Total Security is a good software, but I have some complains. When one searches for files to clean-up, the program might indicate 20Gb to clean up. You do the cleanup and afterwards search again: the same value is displayed, which sounds weird to me. If for some reason, some files can not be cleaned up, fear enough, but then say so or do not put them in the clean-up list.

Kaspersky are releasing a free version of their antivirus. Announcement and details here:

More details on this article on Ghacks:

Kaspersky and BitDefender are consistently the highest rated antivirus softwares, year after year. So I jumped at this opportunity. One day later, I've uninstalled Kaspersky.
Why? When browsing the internet, I kept getting popups "Attention! Your confirmation is required to perform the selected action. This action will reduce the protection of your computer." And when I say "OK" to that one, another one pops up with a warning about the certficate for that website.
These are websites that I visit regularly with no problem.
Plus: there are a dozen or more notifications sent to the Windows Action Center every day.
The whole thing is just a big pain to deal with.

Thank you for the feedback. I do not plan to install it on my main system, but I might on my secondary laptop, to try it out. But from what you describe, it will be a pain to encounter such messages on even good sites. Maybe you can whitelist those sites somewhere? I was thinking of installing it on computers of my friends and relatives, since it seems like a good option. Maybe for us experienced users, these messages may be a bit of a pain to deal with, but for inexperienced ones, these might be helpful. It will be available in India in September, so I can try it only then.

I installed this earlier in the week. Seems to be fine. Light on resources and not difficult to use.
(Had happily been using Avast until now)!
One point though:
this as this function will use "considerable computer resources"!!!
I prefer to have an Anti-Virus solution that is as LIGHT as possible!
Besides this...seems to be working perfectly.

360 Total Security is a decent program although too bloated for my tastes like most of the leading commercial programs.
I prefer Bitdefender AV 2017 Free in conjunction with their separate free Anti-ransomware app.
Industry leading protection in all independent testing and very light on resources.
Very minimalist interface with virtually no input required from the user plus it was rated by the CIA's hackers as the most difficult AV to penetrate (in fact they could not hack computers protected by BD according to the Wikileaks recent release of internal CIA secret documents) and the free version uses the same scan engine and technology as their paid versions according to tests done by Neil Rubenking.
Most of the free AV program available these days are good and I guess it is more a question of meeting the needs and expectations of individual users.

For Windows 10 users the latest Bitdefender Free AV coupled with their stand alone BD Anti-Ransomware which is also free offers excellent protection.
Same highest rating results as their commercial product but very lightweight, unobtrusive and free. Not configurable which won't please the geeks but a great option for the average user in my opinion.
The latest version of Bitdefender AV Free will only work with Windows 7 Service Pack 1 through to Windows 10.

For 360 you wrote "light on resources" and yet the essential version i have installed uses nearly 500mb of ram and 900mb of VM on my windows 7 x64.

Strange. It used to use only 60MB when I had a resident antivirus running on my system. And around 80-90MB with Bitdefender and Avira engines enabled out of the total 8GB RAM available. I don't recommend running the Essentials version [TSE] because it's slow to update [still at v8 compared to v9 for TS] and doesn't get all the fixes that Total Security [TS] gets. I haven't tested on Windows 7 though as all these results are from Windows 10.

I am trying to install BitDefender Free
Their 2016 version won't install in XP (or Vista)
I have nearly gone insane attempting to get their FREE XP version (it is the 2015 version)
I managed to get a link (to the 2015 version) from the 2016 failed install.
But I cannot work out whether if that is their free version.
Can anyone point me to the free XP version ?

From the product website: - "Operating system: Windows 7 Service Pack 1, Windows 8, Windows 8.1, Windows 10". Some free solutions such as Avast do still work on XP although protection will be limited at best considering XP is now obsolete and system vulnerabilities are no longer patched. MC - Site Manager.

I find it my self very similar as you described in your reviews. 360 is the best, Comodo has improved a lot in the last years, Avira always been good. But I find it confusing why Quihoo's 360 is not represented in the big AV-Comparatives? Neither Comodo... I recommend you one more antivirus to review: Sophos Home. Is the third biggest security company on the world (behind Norton and Kaspersky), light on resources (cloud), very simple to use and in quite a few tests (Scanning speed, resource management, total hits, etc...) is in the top of the AV softwares.

Qihoo 360 was removed from av-comparative, AV-TEST and Virus Bulletin because they were cheating. You can googled for the news. I'm going to share the link, but when trying to post my comment, it was blocked.

I've tried Sophos Home recently and I am not yet convinced of using it beyond my tests. Detection can be very good but on AV Comparatives it's overall real world detection is similar to Windows Defender, sometimes worse! For resources, on my PC it has 6-8 various components which when idle total around 300mB of RAM, that's a lot and although I have 8GB RAM the PC feels a bit sluggish especially when browsing. It's also a pain having to go into the online control panel to add exceptions and other tasks rather than doing it immediately and smoothly in the client software.

Also re-tried Avira recently. I found it's heuristics to be really excellent, unlike the review above, especially on identifying macro viruses and trojan downloaders which then download Locky and other ransomewhere. In my tests Avira detected all zero day stuff that had just arrived in my mailbox and this was confirmed as brand new on Virustotal and with Avra being in the first bunch of 7-10 detectors out of 55 that quickly, even immediately detected these things. On the downside, once detected, cleanup is very slow which would not be a problem but it leaves lots of remnant files and folders which is confusing and makes the user think that the malware is still there. Also the interface is not only very old but also quite confusing. The seperate program / process of Luke Filewalker is just plain ridiculous in my view, it should be integrated fully and seamless.

Tried most others but currently still on Windows Defender because it has the least impact and the best cleanup but detection although much improved this year needs to be a lot higher.

The latest beta of free Bitdefender looks promising but whilst it remains a beta I won't be trying it.

Avira has not been compatible with XP for more than two years - .

For those still running XP (and which should be utilizing the Registry hack to enable receiving the WEPOS updates -, Bitdefender Free is a lightweight solution that has demonstrated adequate protection on the several machines that I have had it installed on.

I read that Avira has the best privacy policy.

Not for nothing, could you elaborate on how Windows Defender improved in Windows 10 despite the bashing it still, and always gets?

If it is better, why are others still not using it? Or is it the negative, or maybe proven hype?


When I upgraded to W10 Pro, I was prepared to give Windows Defender a try.
My PC is not powerful, and when I noticed it getting sluggish sometimes, I checked and Win Defender was busily scanning my drive (even inside zip files) when no scan had been scheduled or requested.
I like to control what is happening, and when, so Windows Defender is gone.

Qihoo 360 Total Security light? Not here. RAM usage for all processes averages around 70MB (balanced mode, without Avira and Bitdefender engines) compared with around 15MB for my previous AV, Panda Free. 360 TS is far too bloated. Also, less experienced users need to be very wary of what's being deleted/changed if they use any of the optimization tools. Certainly not recommended by me.

360TS uses 70MB on my system with Avira and Bitdefender engines enabled.

How do you turn them on ?

Click on the Protection tab in the Left side bar of the UI and then click on Custom settings. Scroll down and enable any of the engines you like and press OK. Now go to Virus scan tab in the left side bar, and then on the bottom move the slider bar to green over the Avira/Bitdefender engines.

If it was me I would enable them only during on-demand scans, and disable it in real-time.