The 11 Best Free Antivirus Software of 2021

Protect your Windows computer with a free antivirus program

A good antivirus program is essential to a secure system, and you most definitely do not have to pay for one to get great protection. Below is our hand-picked list of the 11 best free antivirus programs that you can download for Windows today.

All of these programs perform definition updates automatically, are always running to make sure your files are protected from malware and your personal information remains private, and can start scans on-demand whenever you like.

However, each of them do have a few prominent differences that make them stand out, so pay attention to those as you decide which one to use.

If you just need a spyware cleaner and need it right now without waiting for one of these full AV programs to install, use one of the (preferably portable) applications from our Best Free Spyware Removal Tools list. There are also free on-demand virus scanners you can install. Also, consider using a Windows Firewall alternative from this Free Firewall Programs list.

If you can’t even log in to Windows to install an antivirus tool, access a computer that does work and then use it to make a free bootable antivirus tool that you can then run on the infected computer.

Avira Free Security

Password manager included.

Optional additional downloadable protection layers.

In-the-cloud antivirus process.

Additional features can be annoying.

Add-on components often require fee to be fully functional.

The main component in Avira’s free software suite that makes it stand out is the optional «in-the-cloud detection» feature called Protection Cloud. This scanning method lets Avira’s antivirus tool identify and stop threats before they get out of hand.

This is how it works: When a suspicious file is detected on any computer running Avira, a fingerprint of that specific file is generated and uploaded anonymously to Avira so that they can scan it and report its status (whether it’s safe or dangerous) back to every Avira user so that the program can take appropriate action.

Avira can scan and remove existing threats as well as automatically detect and stop new ones. It protects you against ransomware, Trojans, spyware, and other kinds of malware. You can even choose which ones to actively watch out for, and disable others (though it’s not recommended) like dialers, jokes, adware, etc.

Avira Free Security can also scan on a schedule, check files with any file extension or just the ones you manually choose from, disable the ability to stop active scans (so that viruses can not stop the program from finding them), adjust the scanner’s priority level, scan primary boot sectors, follow symbolic links to scan the actual files, search for rootkits before starting a scan, scan the Windows Registry, ignore files on network drives, automatically repair, rename, quarantine, delete, or ignore threats when they’re found, use heuristic scanning, add files, folders, and processes to the ignore list, manage Windows Firewall settings, password protect the program’s settings, block autorun on removable devices, and make the hosts file read-only.

This program offers more than just a very extensive antivirus application. It includes several other «layers» of security that will install automatically, and they might take a while to download since there are several. However, you don’t have to use them, and they won’t bother you unless you open them.

These separate modules include a VPN that encrypts all your traffic (up through the first 500 MB each month); password manager to securely store complex passwords; and software updater that identifies outdated programs and gives you the download links to update them.

In addition, Avira can speed up your computer and reduce boot time with its tune-up tool, help you find the best deals as you shop online, and warn you of malicious websites or software bundles before you download them (with its SafeSearch add-on).

These extra features can be annoying if you’re strictly after an antivirus solution, but again, you don’t have to use them; just keep them tucked away where they are and you won’t have to worry about them.

Avira Free Security is intended to run on computers with Windows 7 and newer, including Windows 10 and Windows 8. There’s also Avira for macOS.

Bitdefender Antivirus Free Edition

Drag-and-drop file and folder scan.

Minimal, uncluttered design.

Simple to set up and run.

Limited customization if you’re looking for that.

Takes a while to install.

If you want an antivirus program that’s not only free but easy to use and not cluttered with lots of buttons and menus, you should definitely try the free version of Bitdefender Antivirus.

You not only get instant protection against viruses, worms, rootkits, spyware, and other threats, but also anti-phishing and anti-fraud protection to carry security with you when you’re browsing the internet and entering passwords.

It’s remarkable how well Bitdefender runs despite its minimal design. Drag and drop folders and files directly into the program to run a scan against them, as well as start a full system scan or scan select objects from the right-click context menu—all of which can run at the same time.

Regardless of how they’re started or how many scans are running simultaneously, a history of those scans are recorded for you on the primary window of the program as well as within the Events area of the settings.

The obvious downside to a program that lacks many customization options is that there isn’t much you can change about it. That might be something you want but it might not be available—all you can do with this edition of Bitdefender is start and stop scans.

Another downside to this software is how long it takes to become ready for you to use. The initial installer for Bitdefender is quite small but that’s just what’s used to then download the full program, which is hundreds of megabytes and could take a while if you have a slow internet connection.

It’s also unfortunate that you can’t pause scans (it just lets you stop them) or set up file and folder exclusions before starting scans like some AV programs allow. With Bitdefender, you can only mark files or websites as safe after they’ve been identified as potentially malicious.

Ads asking you to purchase Bitdefender’s professional programs and scheduled scans not being supported (but they’re not necessarily needed since Bitdefender is always checking for new threats) are a few other not-so-greats.

Bitdefender Antivirus Free Edition runs on Windows 10, Windows 8, and Windows 7.

Adaware Antivirus Free

Lightweight antivirus program.

Can run as a supplement to other antivirus programs.

Silent mode mutes notifications and limits resource use.

Some useful features are only usable with paid version.

Real-time email scanning not included.

Adaware Antivirus installs in minutes, is light on system resources, and can be used in one of two ways. The first is in regular mode where it checks for threats as they happen, but the other lets you use it in addition to your primary antivirus program.

What this so-called «second line of defense» does is disables real-time protection but still lets you use Adaware Antivirus to manually scan for existing threats. This feature is helpful if your primary AV software doesn’t seem to find malware that you know is infecting your computer.

Whichever way you use it, Adaware Antivirus provides a defense against ransomware, spyware, viruses, and other forms of malicious software. You can find those threats through a quick, full, or custom scan.

Daily, weekly, and monthly scheduled scans are supported, and you can even run a scan to just check certain things, like only rootkits or just tracking cookies and boot sector viruses, for example.

Adaware Antivirus also lets you choose a custom performance setting to use more system resources to run the scan (to make it faster), exclude files/folders/file extensions from scans, and decide how often to check for new definition updates (every 1/3/6/12/24 hours).

For real-time protection, you can toggle on or off the following options: scan archive files, scan email databases, deep scan that checks CHM files and executable files, smart scan that skips previously checked files, scan boot sectors, scan files as they move throughout the network, and skip scanning files that exceed a custom file size (e.g., 10 MB to skip video files).

You can also protect the program’s settings with a PIN as well as enable gaming/silent mode to suppress notifications.

Adware Antivirus definitely has its advantages but because there’s also a non-free version you can upgrade to, many additional options are not supported.

For example, parental controls and advanced network, web, and email protection are only available in Adaware Antivirus Pro. These options are visible within the free edition, but they’re not actually clickable/usable until you enter a Pro license key.

Adaware Antivirus Free works with Windows 10, Windows 8, and Windows 7.

Avast Free Antivirus

Add-ons allow you to increase protection.

Password manager and some other tools included are trial only.

Additional features require purchase.

Avast is used by hundreds of millions of people and ranks high in nearly every «best list» of antivirus programs, and for good reason. If you want a solid program that is sure to block new threats but is still easy enough to customize, you should consider using it.

Avast Free Antivirus is similar to Avira; supplemental modules enhance the virus shield and provide additional services related to security and privacy.

The antivirus portion has lots of options you can change but it’s still easy enough for anyone to use since there are information blurbs next to most items so you’re not left wondering what will happen if you enable them.

Plus, both definition and program updates are performed automatically (a manual option is available, too), meaning you can install Avast and let it do its thing without worrying whether you’re running the latest and greatest version.

Avast is customizable and lets you make changes to everything from whether to make a sound when threats are detected and how long notifications should remain on the screen, to the kinds of file extensions that should be scanned.

Here are some more features supported in this program: scheduled scans, custom scans that can check only the memory, rootkits, auto-start programs, etc., checking all files or just certain file extensions, protecting against ransomware, identifying files by their content instead of their suffix, fine-tuned heuristics sensitivity, scanning for potentially unwanted programs, follows shortcuts to scan the real file, scan archives like self-extracting DOS and Win32 executables and 7Z and RAR, Windows Explorer context menu integration, exclusions for folders, HDDs, and URLs (but not specific files), custom scans that are easy to save for use in the future, a Rescue Disk utility lets you use the Avast scanner even if you can’t start your computer, particular areas of the program can be protected with a password, and Do Not Disturb Mode.

Before Avast is installed, you have the option to include over a dozen different tools: file, behavior, web, and mail shields; software updater, browser cleaner, rescue disk, Wi-Fi inspector, security and SafePrice browser extensions; password manager; junk file cleaner; and Game Mode.

Technically, if you only want the antimalware protection, you can install just the shields from the start of that list; the others are add-ons that aren’t necessary but could be helpful at some point.

For example, the software updater is a nice tool that will not only check for and report outdated software but also install the newer versions for you (even in bulk).

Wi-Fi Inspector scans the network for devices that could be vulnerable to attacks. For instance, it might identify that a computer is running a file sharing service that has been known to facilitate the spread of a certain kind of worm.

You can install these tools (it takes less than five minutes) and then disable or completely remove them later. Or, you can ignore them during setup and just install them later, or not at all.

However, the password manager and Cleanup tools are only trial versions that will expire after a time-limited trial. There’s also a firewall, file shredder, and sandbox feature that’s unusable in this free version.

Avast Free Antivirus is compatible with Windows 10, 8, and 7. There’s also a Mac and Android version.

See our comparison between Avast and Bitdefender to see which one might be better for you.

The Best Free Antivirus Protection for 2021

Windows Defender is improving, but you still shouldn’t rely on it by itself. That doesn’t mean you have to pay extra, though! We’ve tested the top free antivirus apps so you can protect your PC for free.

Our 10 Top Picks

Best for Wealth of Bonus Features

Avast Free Antivirus

Best for Excellent Lab Test Scores

Kaspersky Security Cloud Free

Best for Few-Frills Protection

AVG AntiVirus Free

Best for Set-and-Forget Protection

Bitdefender Antivirus Free Edition

Best for Managed Family Protection

Sophos Home Free

Best for Many Security Components

Avira Free Security

Best for Windows Diehards

Microsoft Windows Defender Security Center

Best for Personal Firewall Fans

Check Point ZoneAlarm Free Antivirus+

Best for No-Frills Protection

Adaware Antivirus Free

Best for Managed Family Protection

Qihoo 360 Total Security

Compare Specs The Best Free Antivirus Protection for 2021

Free Malware, Spyware, and Adware Protection

Some people optimistically say the best things in life are free, while others dourly contend that you only get what you pay for. When it comes to antivirus software, it turns out that the rosier viewpoint is correct. You can get surprisingly capable protection without having to pay anything. So, what are you waiting for? Install free protection immediately! Once it’s up and running, take your time reading this article and our reviews. If you feel a different free antivirus would suite you better, switching doesn’t cost you anything. We’ve tested both free and commercial antivirus tools to help you choose.

Your antivirus should definitely have the ability to root out existing malware, but its ongoing task is to prevent ransomware, botnets, Trojans, and other types of nasty programs from getting a foothold. All of the antivirus programs in this collection offer real-time malware protection. Some take the fight to the browser, working hard to ensure you never even browse to a malware-hosting site, or get fooled into turning over your credentials to a phishing site.

Free Antivirus vs. Paid Antivirus

If free antivirus tools are so great, why should anybody pay? For one thing, quite a few of these products are free only for noncommercial use; if you want to protect your business, you must pony up for the paid edition. At that point, you should probably consider upgrading to a full security suite. After all, it’s your business’s security on the line.

Even for personal use, most for-pay antivirus tools offer more than their free counterparts—sometimes a lot more. For example, ZoneAlarm’s paid edition adds protection against malicious and fraudulent websites that the free version lacks. And Panda reserves quite a few features for paying customers, among them firewall protection, application control, cross-platform support, and detection of insecure Wi-Fi connections.

The Best Antivirus Deals This Week*

*Deals are selected by our partner, TechBargains

• McAfee Total Protection — $69.99 for 10-Devices on a 2-Year Plan(List Price $239.98)
• Norton AntiVirus Plus — $19.99 for 1-Device on 1-Year Plan(List Price $59.99)
• Bitdefender Total Security — $39.98 for 5-Devices on 1-Year Plan(List Price $89.99)
• Webroot SecureAnywhere — $18.99 for 1-Device on 1-Year Plan(List Price $39.99)
• VIPRE Ultimate Security — $39.99 for 5-Devices on 1-Year Plan(List Price $139.99)

In addition, many companies don’t offer full-scale tech support for users of the free edition. The first time you need extra help digging a particularly stubborn piece of malware out of your system, you might regret the lack of support.

Independent Antivirus Lab Test Results

Around the world, researchers at independent antivirus testing labs spend their days putting antivirus tools to the test. Some of these labs regularly release public reports on their findings. We follow four such labs closely: AV-Comparatives, MRG-Effitas, SE Labs, and AV-Test Institute. We also take note of whether vendors have contracted for certification by ICSA Labs and West Coast Labs.

Security companies typically pay for the privilege of being included in testing. In return, the labs supply them with detailed reports that can help improve their products. The number of labs that include a particular vendor serves as a measure of significance. In each case, the lab considered the product important enough to test, and the vendor felt the price was worthwhile. The labs don’t necessarily test a vendor’s free product, but most vendors pack full protection into the free product, enhancing premium versions with additional features.

We Test Malware Protection

In addition to carefully perusing results from the independent labs, we also run our own hands-on malware protection test. We expose each antivirus to a collection of malware samples, including a variety of different malware types, and note its reaction. Typically, the antivirus will wipe out most of the samples on sight and detect some of the remaining ones when we try to launch them. We derive a malware blocking score from 0 to 10 points based on how thoroughly the antivirus protects the test system from these samples.

Since we use the same samples month after month, the malware-blocking test doesn’t measure a product’s ability to detect brand-new threats. In a separate test, we attempt to download malware from 100 very new malicious URLs supplied by London-based testing lab MRG-Effitas, typically less than a few days old. We note whether the antivirus blocked all access to the URL, wiped out the malicious payload during download, or did nothing. Sophos Home Free managed 100 percent protection in its latest test, as did McAfee and Vipre.

If you’re interested in learning more about our testing techniques, you’re welcome to read more about how we test security software.

Useful Features

Just about every antivirus product scans files on access to make sure malware can’t launch, and also scans the entire system on demand, or on a schedule you set. Once that cleaning and scheduling is done, blocking all access to malware-hosting URLs is another good way to avoid trouble. Many products extend that protection to also steer users away from fraudulent websites, phishing sites that try to steal login credentials for financial sites and other sensitive sites. A few rate links in search results, flagging any dangerous or iffy ones.

Behavior-based detection, a feature of some antivirus products, is a two-edged sword. On the one hand, it can detect malware that’s never been seen before. On the other hand, if it’s not done right, it can baffle the user with messages about perfectly legitimate programs.

Any antivirus should eliminate spyware along with other types of malware, but some products include features designed specifically for spyware protection. Features like encryption to protect your sensitive data and webcam control to prevent remote peeping typically show up in commercial products, not free ones. But some free products include features like a simple on-screen keyboard to foil keyloggers.

One easy way to keep your PC protected is to install all security updates, both for Windows and for browsers and other popular applications. Windows 10 makes it easier than ever to stay up to date, but there are plenty of security holes in older Windows versions, in popular apps, and in add-ons. Scanning for vulnerabilities in the form of missing updates is a feature most often found in commercial antivirus products, but it does turn up in some free ones. In the list below you can see which products include these useful features.

What’s Not Here?

Previous editions of this article reported only on free antivirus products that received at least a good rating in our reviews—three stars or better. A couple of the listed products lost ground recently. Poor performance in testing brought Adaware and Qihoo 360 down to 2.5 stars. We’ve kept them in the roundup, so you can see how they stack up, but we don’t recommend them.

Microsoft Windows Defender Security Center moved up to a three-star score a few years ago; it’s now at 3.5 stars. Yes, it’s more of a Windows component than a free product. Yes, the very best free antivirus utilities offer many more layers of protection. But Windows Defender protects everyone who can’t be bothered to install a third-party antivirus tool.

Several free utilities devoted entirely to ransomware protection have come on the scene in the last few years. Alas, several of those have fallen by the wayside, among them Bitdefender Anti-Ransomware, Cybereason RansomFree, and CyberSight RansomStopper. In any case, these are useful companion products, but they don’t do the job of a full-scale antivirus utility.

There are also numerous free antivirus utilities that work solely to clean up existing malware infestations. You bring out these cleanup-only tools when you have a nasty malware problem. When the malware’s gone, they have no further use, since they offer no ongoing protection. Our favorite in this category is Malwarebytes Anti-Malware, and it’s one you should try if you’ve got a malware problem. But since they’re free, you can keep trying others if the first one doesn’t do the job. When the scare is over, you’ll need a full-blown antivirus for ongoing protection.

Which Free Antivirus Is Best?

Our current Editors’ Choice picks for free antivirus utility are Avast Free Antivirus and Kaspersky Security Cloud Free. Both appear in lab reports from all four labs we follow. Kaspersky earned near-perfect scores, and Avast came close. We did strip Avast’s Editors’ Choice award last year after a privacy problem with sharing of user data. That problem was solved, so we’ve taken Avast out of the penalty box. If you do have a little cash in your budget for security, the best paid antivirus software does offer more and better protection. If not, try a few of these free tools and see which one you like best.

Worried you might already be infected? Check out our article on the signs you have malware.