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For most Windows 10 and Windows 11 users, Microsoft Defender Antivirus is the best free starting point. It is built into Windows, provides real-time protection through Windows Security, updates with the operating system, and requires no separate account or subscription. In AV-TEST’s June 2026 Windows 11 evaluation, Defender scored 17.5 out of 18.
Choose Avast One Essential or AVG AntiVirus Free if you specifically want a third-party dashboard and additional web, email, link, or Wi-Fi controls. Use Malwarebytes Free primarily as an on-demand second-opinion scanner—not automatically as a replacement for real-time antivirus.
Quick picks
| Product | Best for | Real-time protection | Important caveat |
|---|---|---|---|
| Microsoft Defender Antivirus | Most Windows users | Yes | Some advanced identity and web features depend on Microsoft or browser services |
| Avast One Essential | A feature-rich free third-party suite | Yes | Expect extra notifications and paid-upgrade prompts |
| AVG AntiVirus Free | A straightforward third-party alternative | Yes | It belongs to the same broader corporate family as Avast and is licensed for personal and family use |
| Malwarebytes Free | Manual cleanup and second opinions | Generally on-demand | Do not treat it as a full free real-time replacement without checking the current edition |
Is free antivirus good enough?
Yes—free antivirus can provide effective malware detection, malicious-download blocking, attachment scanning, and real-time protection. But antivirus is only one layer of security. It does not make phishing, account theft, software vulnerabilities, scams, or data loss disappear.
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A free scan shows the junk files, broken settings and background clutter dragging Windows down - then fixes them in one click.Free scan · Windows 10 & 11A free antivirus cannot compensate for an unpatched operating system, reused passwords, missing multifactor authentication, pirated software, unsafe browser extensions, or the absence of backups. Ransomware protection and exploit controls also vary by product and edition. Treat marketing claims about “complete protection” cautiously: laboratory results apply to a particular product version, operating system, test period, and threat sample.
#1 Best Overall
- SPEED-OPTIMIZED, CROSS-PLATFORM PROTECTION: World-class antivirus security and cyber protection for Windows (Windows 7 with Service Pack 1, Windows 8, Windows 8.1, Windows 10, and Windows 11), Mac OS (Yosemite 10.10 or later), iOS (11.2 or later), and Android (5.0 or later). Organize and keep your digital life safe from hackers
- SAFE ONLINE BANKING: A unique, dedicated browser secures your online transactions; Our Total Security product also includes 200MB per day of our new and improved Bitdefender VPN
- ADVANCED THREAT DEFENSE: Real-Time Data Protection, Multi-Layer Malware and Ransomware Protection, Social Network Protection, Game/Movie/Work Modes, Microphone Monitor, Webcam Protection, Anti-Tracker, Phishing, Fraud, and Spam Protection, File Shredder, Parental Controls, and more
- ECO-FRIENDLY PACKAGING: Your product-specific code is printed on a card and shipped inside a protective cardboard sleeve. Simply open packaging and scratch off security ink on the card to reveal your activation code. No more bulky box or hard-to-recycle discs. PLEASE NOTE: Product packaging may vary from the images shown, however the product is the same.
Use automatic updates, unique passwords, multifactor authentication, reputable browser extensions, and at least one offline or otherwise inaccessible backup. Antivirus should support those habits, not replace them.
Microsoft Defender: the best default for Windows
Microsoft Defender Antivirus is included with supported Windows 10 and Windows 11 installations. It works through the Windows Security app alongside Windows Firewall and other Windows security controls. Microsoft says Defender can turn off when another antimalware product is installed and can turn back on after that product is removed or expires.
In AV-TEST’s June 2026 Windows 11 test, Defender received 6/6 for protection, 6/6 for performance, and 5.5/6 for usability, for a total of 17.5/18. Avast Free Antivirus and AVG Antivirus Free each scored 18/18 in that same test. This does not make Defender inferior: its biggest advantage is that it is already installed, updated through Windows, and integrated into the operating system.
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Defender is the right choice if you want no extra software, no separate renewal, and minimal system complexity. A third-party product may be preferable if you specifically want a different interface or additional vendor-provided web, email, Wi-Fi, or scanning controls.
How to check and configure Defender
- Open Start, search for Windows Security, and open it.
- Select Virus & threat protection.
- Under “Virus & threat protection settings,” select Manage settings.
- Confirm Real-time protection is on.
- Confirm Cloud-delivered protection is on.
- Confirm Automatic sample submission is on, unless your privacy preference requires otherwise.
- Check App & browser control, Firewall & network protection, and Device security.
- Open protection updates, install the latest definitions, and run a Quick scan.
Use a Full scan when you have a specific reason to suspect an infection. Use Microsoft Defender Offline when normal Windows scanning may be disrupted by persistent malware. Microsoft’s antivirus FAQ documents these settings and scanning choices.
If Defender is disabled
First check whether another antivirus, including an expired paid trial, is installed. Remove the unwanted real-time product, restart Windows, install pending Windows updates, and reopen Windows Security. Do not deliberately leave the computer without an active real-time provider.
Rank #2
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- ONGOING PROTECTION Download instantly & install protection for 5 PCs, Macs, iOS or Android devices in minutes!
- TOP-PERFORMING VPN Faster speeds, more server locations, and greater connection control to protect your privacy across all your devices, including Smart TVs.
- ADVANCED SCAM PROTECTION Help spot hidden scams online. With the built-in Genie AI assistant, you’ll never wonder if a message or email is suspicious again.
- REAL-TIME PROTECTION Advanced security protects against existing and emerging malware threats, including ransomware and viruses, and it won’t slow down your device performance.
- DARK WEB MONITORING Identity thieves can buy or sell your information on websites and forums. We search the dark web and notify you should your information be found.
Avast One Essential: best third-party free option
Avast One Essential is a reasonable choice for users who want a more prominent third-party security dashboard. Avast promotes free real-time protection alongside features such as web protection, email protection, Wi-Fi scanning, scam-related tools, and ransomware-related safeguards. The exact free feature set can vary by platform and region, so check Avast’s free-and-paid feature list during installation.
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Avast Free Antivirus scored 6/6 in protection, performance, and usability in AV-TEST’s June 2026 Windows 11 evaluation. That is strong evidence for the tested edition, not a guarantee against every future threat.
The trade-off is complexity. Avast may show more notifications, account prompts, upgrade offers, and background services than Defender. Review privacy and data-sharing choices, decline optional bundled software, and make sure you know which features are genuinely free rather than trial-only.
AVG AntiVirus Free: a simple alternative
AVG AntiVirus Free provides real-time protection and advertises web, email, link, and attachment controls. It also scored 6/6 for protection, performance, and usability in AV-TEST’s June 2026 Windows 11 test.
AVG and Avast are not entirely independent technical choices: they belong to the same broader corporate family. Choose AVG if you prefer its interface or installation experience, not because it represents a completely separate antivirus ecosystem.
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Rank #3
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- ONGOING PROTECTION Download instantly & install protection for 10 PCs, Macs, iOS or Android devices in minutes!
- TOP-PERFORMING VPN Faster speeds, more server locations, and greater connection control to protect your privacy across all your devices, including Smart TVs.
- ADVANCED SCAM PROTECTION Help spot hidden scams online. With the built-in Genie AI assistant, you’ll never wonder if a message or email is suspicious again.
- REAL-TIME PROTECTION Advanced security protects against existing and emerging malware threats, including ransomware and viruses, and it won’t slow down your device performance.
- DARK WEB MONITORING Identity thieves can buy or sell your information on websites and forums. We search the dark web and notify you should your information be found.
Malwarebytes Free: useful second opinion, not the default antivirus
Malwarebytes Free is most useful for manual, on-demand scans when you suspect unwanted software or want a second opinion. It should not be presented as equivalent to a free product that continuously monitors the device unless the current edition and settings explicitly provide that function.
You can use Malwarebytes alongside Defender for occasional manual scans, but inspect its settings carefully. A trial or enabled real-time module may change how Windows selects its active antivirus provider. Running two full real-time antivirus products simultaneously can cause conflicts and performance problems.
What independent tests show
Independent tests are useful, but only when you compare the same operating system, edition, version, test category, and period.
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| Product | Protection | Performance | Usability | Total |
|---|---|---|---|---|
| Microsoft Defender Antivirus | 6/6 | 6/6 | 5.5/6 | 17.5/18 |
| Avast Free Antivirus | 6/6 | 6/6 | 6/6 | 18/18 |
| AVG Antivirus Free | 6/6 | 6/6 | 6/6 | 18/18 |
See the full AV-TEST Windows 11 results for the test methodology and other products.
AV-Comparatives: different tests, different measurements
AV-Comparatives’ February–May 2026 Real-World Protection Test evaluated products in a realistic browsing environment. Its March 2026 Malware Protection Test used fully updated 64-bit Windows 11 systems. These are separate tests from AV-TEST and should not be blended into one universal score.
Performance also varies independently from protection. In AV-Comparatives’ April 2026 performance test, the reported impact scores included 12.9 for Microsoft, 5.5 for Avast/AVG, 9.6 for Bitdefender, and 17.6 for Malwarebytes. Lower impact in that particular test does not establish a universal ranking: hardware, methodology, product settings, and test activities matter.
Rank #4
- THREAT DETECTION – Stay one step ahead. Suspicious links, risky sites, viruses, and scams, caught automatically before they reach you.
- PERSONAL INFO PROTECTION – Keep your personal info safer. Identity monitoring watches for your exposed info and tells you what to do about it.
- SECURE CONNECTIONS – Just a few easy clicks, and we'll automatically protect your info on public Wi‑Fi, every time you connect.
- GUIDED ACTION – Know what matters and what to do next. Clear alerts and simple guidance make it easy to take action.
- MORE THAN ANTIVIRUS – Scam protection, identity monitoring, VPN, web protection, and antivirus work together to protect you, all in one place.
Also avoid transferring a paid product’s result to a free edition. For example, AV-Comparatives’ listed Bitdefender results concern Bitdefender Total Security, not automatically a free Bitdefender product.
Free antivirus by device
Windows
Windows has the clearest free-antivirus choice: start with Defender. Install Avast or AVG only when their additional controls or interface justify the extra software. Keep one real-time antivirus active.
Mac
macOS is not immune to malware. Third-party protection may be worthwhile if you install unsigned or pirated software, download heavily, share files with Windows users, need cross-platform scanning, or must meet a school or business requirement. Windows test results do not apply to macOS.
Android
Reputable mobile security can be especially useful if you sideload applications, install apps outside Google Play, download files frequently, or use an older device. AV-TEST separately evaluates Android products. In its May 2026 displayed results, Avast Antivirus & Security, AVG Antivirus Free, and Bitdefender Mobile Security each received 6/6 for protection, performance, and usability. These results do not imply identical protection on Windows or iPhone.
iPhone and iPad
Be cautious with the word “antivirus” on iOS. The platform limits what conventional security apps can scan and continuously monitor. Many iPhone security apps focus instead on phishing, unsafe Wi-Fi, VPN features, identity monitoring, or breach alerts rather than traditional device-wide malware scanning.
How to install third-party free antivirus safely
- Remove any unwanted existing third-party real-time antivirus and restart if prompted.
- Download only from the vendor’s official website or the official app store.
- Decline optional bundled software and paid-trial upgrades where possible.
- Review privacy and data-sharing choices.
- Confirm that real-time protection is enabled after installation.
- Update the application and threat definitions.
- Run an initial scan.
- Open Windows Security and verify which antivirus provider is active.
Do not install software from a fake browser warning or a pop-up claiming that your computer is infected. Microsoft advises checking the source of antimalware software carefully; scammers distribute bogus security alerts and installers.
Best Value
- POWERFUL, LIGHTNING-FAST ANTIVIRUS: Protects your computer from viruses and malware through the cloud; Webroot scans faster, uses fewer system resources and safeguards your devices in real-time by identifying and blocking new threats
- IDENTITY THEFT PROTECTION: Protects your usernames, account numbers and other personal information against keyloggers, spyware and other online threats targeting valuable personal data
- REAL-TIME ANTI-PHISHING: Proactively scans websites, emails and other communications and warns you of potential danger before you click to effectively stop malicious attempts to steal your personal information
- ALWAYS UP TO DATE: Webroot scours 95% of the Internet three times per day including billions of web pages, files and apps to determine what is safe online and enhances the software automatically without time-consuming updates
When “free” is not really free
Before installing, check whether the product offers permanent protection or merely a time-limited premium trial. Also check whether it requires an account, displays advertisements, limits features by country, covers one device only, or automatically renews a paid subscription.
A legitimate free tier may still promote paid features. That is different from a trial that becomes a subscription. Read the installation screens and confirmation emails, and do not enter payment details unless you intentionally want the paid plan.
Should you pay for antivirus?
Many Windows users do not need to. A paid suite becomes easier to justify when you specifically need multi-device coverage, centralized support, parental controls, identity monitoring, a VPN, password management, or additional ransomware controls.
Compare the actual missing feature rather than buying because a vendor claims its free product is inadequate. If you consider a paid plan, separate the first-year price from the renewal price and check the country, tax, device count, promotion, and automatic-renewal terms. Bundles can also duplicate tools you already use.
If you suspect an infection
- Disconnect from the internet if appropriate.
- Do not access banking or email accounts on the suspected device.
- Update security software from a trusted connection.
- Run a Full scan, then use an offline or boot-time scan if normal scanning fails.
- Change important passwords from a clean device.
- Restore from a known-good backup or seek professional help if ransomware or credential theft is suspected.
No free antivirus can promise to clean every infection safely. Serious compromise may require rebuilding the device or professional incident response.
The Bottom Line
Bottom line: Keep Microsoft Defender if you want effective, low-maintenance Windows protection. Pick Avast One Essential or AVG AntiVirus Free for a third-party interface and extra controls, and use Malwarebytes Free as an occasional second-opinion scanner. Whichever product you choose, keep it updated, run only one real-time antivirus, and support it with updates, multifactor authentication, strong passwords, scam awareness, and backups.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
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