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Best overall third-party free antivirus: Avast One with Free Antivirus. Best option with nothing to install: Microsoft Defender Antivirus. Both have strong current independent Windows test results, but neither replaces safe browsing, updates, multi-factor authentication and backups.
Avast One with Free Antivirus is the best full-featured third-party free antivirus for most people using a supported Windows PC. It combines strong current independent test results with real-time malware, phishing, unsafe-site and Wi-Fi protections described by Avast. If you would rather install nothing, Microsoft Defender Antivirus is the best free choice already on your PC.
These recommendations are for consumer Windows PCs. Availability and feature sets vary by country, Windows version and product edition.
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Best free antivirus software at a glance
| Pick | Best for | Why it stands out | Watch out for |
|---|---|---|---|
| Avast One with Free Antivirus | A feature-rich third-party suite | Avast recorded 99.3% protection in AV-Comparatives’ February–May 2026 real-world Windows 11 test and earned 6/6 for protection, performance and usability from AV-TEST in its May–June 2026 home-user test. | Free antivirus products promote paid upgrades. Download only from Avast’s official site and check which features are free before enabling them. |
| Microsoft Defender Antivirus | No-install protection | Built into supported Windows, free, and automatically active when no other real-time antivirus is installed. It recorded 99.0% protection in the same AV-Comparatives test. | It has fewer bundled extras than some third-party suites. Keep Windows and Defender updates enabled. |
| AVG AntiVirus Free | People who prefer AVG’s interface | It matched Avast’s cited independent results, including AV-TEST’s perfect 18/18 score. | AVG uses the Avast engine, so it is not a separate protection technology choice. |
| Avira Free Security | Extra privacy and maintenance tools | Avira says its free bundle includes antivirus, browser safety, a password manager, software updater and 500 MB of VPN traffic per month. | Those are vendor-stated features; the evidence here does not support ranking it above Avast or Defender on current direct free-product lab results. |
| Malwarebytes Free | A manual cleanup or second-opinion scan | The free Windows tier includes Quick Scan and Custom Scan. | Its real-time and web protections are paid features, so it is not a replacement for a free real-time antivirus. |
1. Avast One with Free Antivirus: best full-featured free antivirus
Choose Avast if you want more security tooling than Windows includes by default without immediately paying for a suite. Avast says its free antivirus is delivered through the Avast One app and includes real-time malware detection, blocking and removal; phishing and unsafe-website protection; Wi-Fi security; and an AI-powered assistant for checking suspicious messages or offers.
#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.
There is solid independent support for making Avast the leading third-party pick. In AV-Comparatives’ February–May 2026 Real-World Protection Test, performed on fully patched Windows 11 64-bit systems using updated, cloud-connected products, Avast achieved 99.3% protection and received the lab’s highest award level. AV-TEST’s May–June 2026 Windows home-user assessment gave Avast Free Antivirus versions 26.4/26.5 the maximum 6/6 for protection, 6/6 for performance and 6/6 for usability.
That does not mean every Avast One feature is free. Avast Premium Security adds advanced features and multi-device coverage. Treat optional upgrade prompts as optional, and do not assume a feature shown in the app belongs to the free plan.
2. Microsoft Defender Antivirus: best free antivirus already on your PC
Microsoft Defender is the practical answer for people who want strong protection with no new account, download or upgrade funnel. Microsoft includes it in supported Windows, and it stays on when another antivirus is not installed.
Quick wins for a faster PC:
Scan for outdated or missing drivers - takes under a minuteDriver Scan →Repair Windows errors before they cause bigger problemsFix Now →Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →Its current independent results are close to the leading third-party free options: 99.0% protection in AV-Comparatives’ February–May 2026 real-world Windows 11 test, plus 6/6 for protection, 5.5/6 for performance and 6/6 for usability in AV-TEST’s May–June 2026 test. AV-TEST scores products out of 18; 17.5 or higher qualifies as a Top Product.
Rank #2
![Norton 360 Deluxe 2027 Antivirus, 3 Devices, Auto-Renews [Download]](https://m.media-amazon.com/images/I/41qw3FS3qLL._SL160_.jpg)
- ONGOING PROTECTION Download instantly & install protection for 3 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.
For many households, the simplest safe setup is to leave Defender enabled, allow automatic Windows updates, use a modern browser with its security protections turned on, and improve account security. You do not need a third-party antivirus merely because it advertises more features.
How to check that Defender is active
- Open Windows Security from the Start menu.
- Select Virus & threat protection.
- Confirm that protection is active and that security intelligence updates are current.
- In Windows Update, install any pending Windows updates and leave automatic updates enabled.
3. AVG AntiVirus Free: a valid Avast alternative, not a separate engine
AVG AntiVirus Free is a sensible option if you prefer its layout or familiar branding. AV-Comparatives recorded the same 99.3% protection result for AVG in its February–May 2026 test, and AV-TEST gave AVG Antivirus Free versions 26.4/26.5 a perfect 6/6 in protection, performance and usability.
Do not install AVG alongside Avast in hopes of doubling your protection. AV-Comparatives identifies AVG as using the Avast engine. Pick the interface and free-plan experience you prefer, then run only one of them as your real-time antivirus.
Useful alternatives with narrower roles
Avira Free Security
Avira is worth considering when its extras matter more to you than a top ranking based on the cited lab comparison. Avira advertises browser safety, a password manager, software updater and 500 MB per month of VPN traffic in its free bundle. The VPN allowance is small, so regard it as occasional-use privacy capacity rather than a replacement for an unlimited VPN service.
Rank #3
- 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.
Malwarebytes Free
Malwarebytes Free can be useful when you suspect a problem and want an additional manual scan. Its free Windows offering supports Quick Scan and Custom Scan. However, Malwarebytes lists Windows real-time protection, web protection, scheduled scans and threat scans as paid features. Keep Defender, Avast, AVG or another primary real-time antivirus in place; use Malwarebytes Free only as a manual second opinion when needed.
What the 2026 test results mean—and what they do not
The rankings are informed by two independent Windows test programs:
- AV-Comparatives: Its February–May 2026 Real-World Protection Test used 400 cases on fully patched Windows 11 64-bit systems, with products updated and cloud-connected. Avast and AVG scored 99.3%; Microsoft scored 99.0%. Avast, AVG and Microsoft received the highest award level.
- AV-TEST: Its May–June 2026 Windows home-user test used current publicly available versions with default settings and cloud access. Avast Free Antivirus and AVG AntiVirus Free each scored 18/18. Microsoft Defender Antivirus scored 17.5/18.
These are valuable point-in-time signals, not guarantees. Real-world malware tests are dynamic: threats, websites, cloud verdicts and product updates change, and the same test cannot be reproduced exactly later. A protection percentage is also a result for a product in the lab’s environment and settings, not proof that every individual feature will stop every attack on every PC.
Choose one real-time antivirus, not two
Do not run two real-time antivirus products in parallel. Microsoft warns that multiple antimalware products can cause problems. When you install a compatible third-party real-time antivirus, Defender normally switches off. If you later remove that antivirus, confirm that Defender has turned back on.
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.
A manual on-demand scanner is different from a second always-on antivirus, but read its feature labels carefully. Malwarebytes Free, for example, is appropriate for a manual scan; its always-on protection is not included in the free Windows tier.
How to install free antivirus safely
- Choose your primary product. Use Defender for the simplest setup, or choose Avast One or AVG if you want a third-party free suite.
- Download from the vendor’s official website or a trusted platform only. Fake antimalware programs can themselves deliver malware.
- Remove unwanted competing antivirus software. Restart if prompted, then make sure only one real-time antivirus remains active.
- Update immediately. Let the antivirus update its definitions and install available Windows, browser and app updates.
- Run an initial full scan if the product offers one. Follow the product’s instructions for any detected threat; do not disable protection just to install a suspicious file.
- Review notifications. Decline optional paid upgrades or bundled extras you do not want. Keep security notifications enabled.
Antivirus is only one layer of protection
Even the best free antivirus cannot fully protect an account whose password was stolen in a phishing attack, a device that remains unpatched, or files that have no backup. Use these controls alongside your antivirus:
- Keep automatic updates on for Windows, browsers, apps and antivirus definitions. Prompt patching closes known security weaknesses.
- Use unique passwords and a password manager. Turn on multi-factor authentication for email, banking, cloud storage and other important accounts.
- Pause before entering credentials. Verify unexpected links, attachments, QR codes, payment requests and login prompts through a known-good route.
- Back up important files separately. A tested backup limits the damage from ransomware, hardware failure and accidental deletion.
- Use device encryption where appropriate. Encryption helps protect data if a laptop or other device is lost or stolen.
Why Kaspersky is not included for U.S. readers
AV-Comparatives reported a strong 99.8% protection score for Kaspersky in the cited February–May 2026 test. That result does not override availability and regulatory considerations. The U.S. Department of Commerce describes a prohibition on Kaspersky cybersecurity products in the United States, so it is not a recommendation for a U.S.-facing list. This is not a claim that the lab result was inaccurate; it is a separate U.S. availability and regulatory issue.
Methodology and scope
These rankings are for consumer Windows PCs and are informed by AV-Comparatives’ February–May 2026 real-world Windows 11 test and AV-TEST’s May–June 2026 Windows home-user results, together with current official product documentation. Products that share an engine were not treated as independent protection choices. Product features described only by vendors are identified as vendor-stated features. Lab results are snapshots and cannot guarantee protection against every threat.
Best Value
![Norton 360 Deluxe 2027 Antivirus, 5 Devices, Auto-Renews [Download]](https://m.media-amazon.com/images/I/41IYV5zGyCL._SL160_.jpg)
- 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.
Frequently Asked Questions
Is Microsoft Defender good enough in 2026?
Microsoft Defender is a strong default for supported Windows PCs. In AV-Comparatives’ February–May 2026 real-world Windows 11 test it recorded 99.0% protection, and AV-TEST gave it 17.5/18 in its May–June 2026 home-user evaluation. Leave it enabled if you do not want an additional antivirus product.
Can I use Avast or AVG with Microsoft Defender?
No. Microsoft warns that running two antimalware products can cause problems. Choose one real-time antivirus. A manual, on-demand scan from a product such as Malwarebytes Free can have a different role, but it is not a second always-on antivirus.
Is Malwarebytes Free a complete antivirus replacement?
No. Malwarebytes Free includes Quick Scan and Custom Scan, but its Windows real-time protection and web protection are paid features. Use it for manual cleanup or a second-opinion scan, not as your only real-time antivirus.
Should I choose Avast Free Antivirus or AVG AntiVirus Free?
Both had the same cited 2026 independent test outcomes, but AV-Comparatives says AVG uses the Avast engine. Choose one based on the interface and free-plan experience you prefer; installing both does not provide independent protection.
The Bottom Line
Pick Avast One with Free Antivirus if you want the strongest evidence-backed third-party free suite; stick with Microsoft Defender if you want effective protection with no extra software. In either case, run only one real-time antivirus and pair it with updates, MFA and backups.
Quick Recap
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