For a free antivirus option already on your PC, start with Microsoft Defender. If you want an additional download, Avast Free Antivirus, Bitdefender Antivirus Free, AVG AntiVirus Free, and Avira Free Security serve different preferences; Malwarebytes Free is better treated as an on-demand second-opinion scanner than as ongoing real-time protection. A Gizmodo comparison names those six and says to skip Kaspersky, but its ranking reflects that publication’s testing and judgments—not a universal result.
Which free antivirus should you choose?
Choose based on what you need beyond basic malware protection: no installation, a quieter Windows-only app, bundled extras, support for older hardware, or a scanner for a suspected infection. Test scores alone do not settle the choice; edition, test date, hardware, free-tier limits, and upgrade prompts matter too.
| # | Preview | Product | Price | |
|---|---|---|---|---|
| 1 |
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Microsoft Windows 11 (USB) | $128.99 | Buy on Amazon |
| 2 |
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5-in-1 Win Repair & Reinstall Bootable USB Flash Drive – Fix, Recover, or Reinstall Windows 11... | $24.99 | Buy on Amazon |
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| Option | Best fit described by the comparison | Important qualification |
|---|---|---|
| Microsoft Defender | People who want to install nothing new | Included with Windows; AV-TEST’s August 2026 result is for Microsoft Defender Antivirus (Consumer) 4.18. |
| Bitdefender Antivirus Free | People seeking a Windows-only option with little interruption | The comparison says a Bitdefender Central account is required. Do not apply the paid Total Security lab score to this free edition. |
| Avast Free Antivirus | People looking for additional free features, including a ransomware shield and network inspection | The comparison reports a preselected browser install option and recurring paid-product promotions. |
| AVG AntiVirus Free | People with older Windows versions or hardware | The comparison reports strong lab results but also more aggressive prompts and preselected install options. |
| Avira Free Security | People who want a bundle of utilities | The comparison describes a capped VPN, password manager, updater, and cleaner, with some capabilities limited or paid. |
| Malwarebytes Free | People who want a second-opinion scan or help checking a suspected infection | The comparison says its real-time protection does not continue after the 14-day period. |
These use cases and product observations come from the Gizmodo comparison. They are not independent test results from this article. The comparison says it considered independent lab results, one Windows 11 machine restored to a clean image between products, free-tier limits, and paid-plan prompts; it also says scores among its top four were close enough that practical differences affected its ordering.
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AV-TEST scores products in protection, performance, and usability, each worth up to six points, for a maximum of 18. It says 17.5 points qualifies for its “TOP PRODUCT” award. In its August 2026 Windows 11 results, Avast Free Antivirus 26.6 and AVG Antivirus Free 26.6/26.7 each scored 6/6/6; Microsoft Defender Antivirus (Consumer) 4.18 scored 6/5.5/6. Those scores describe the named products and versions in that test, not every free antivirus product or every PC.
#1 Best Overall
- Less chaos, more calm. The refreshed design of Windows 11 enables you to do what you want effortlessly.
- Biometric logins. Encrypted authentication. And, of course, advanced antivirus defenses. Everything you need, plus more, to protect you against the latest cyberthreats.
- Make the most of your screen space with snap layouts, desktops, and seamless redocking.
- Widgets makes staying up-to-date with the content you love and the news you care about, simple.
- Stay in touch with friends and family with Microsoft Teams, which can be seamlessly integrated into your taskbar. (1)
Edition attribution is particularly important. The same August 2026 AV-TEST results page lists Bitdefender Total Security and Avira Internet Security, which are paid suites, rather than Bitdefender Antivirus Free or Avira Free Security. Those paid-suite scores cannot establish how the free editions performed. See AV-TEST’s August 2026 Windows 11 results for the listed editions and scores.
AV-TEST’s separate March/April 2026 Windows 11 test assessed 14 security packages; 12 earned at least 17.5 points. The comparison says that cycle used more than 12,000 malware samples. That is a result from that test cycle, not a prediction that any one product will achieve the same result on a reader’s machine. AV-TEST provides more context in its Windows 11 security-solutions article.
The Gizmodo comparison also reports March 2026 AV-Comparatives results of 99.97% protection and nine false alarms for Avast and AVG, and 99.93% protection and three false alarms for Defender. Those figures are reported by that comparison; the cited AV-Comparatives report is not included here for independent confirmation. The same page describes its own malware measurements on one Windows 11 machine and does not disclose the sample count, so those measurements should not be generalized to all systems.
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Microsoft Defender: the no-download starting point
The comparison recommends Defender for readers who want to install nothing new; it says Defender is included in Windows and enabled by default. Its AV-TEST August 2026 score was 6 for protection, 5.5 for performance, and 6 for usability. If you are satisfied with the built-in protection and want to avoid another account or installer, that makes it the simplest starting point.
Avast Free Antivirus: extra features, with installer and promotion friction
The comparison calls Avast its overall pick and describes a free ransomware shield, network inspection, and scam checking. It reports a June 2026 AV-TEST score of 6/6/6 for the free edition. It also reports that the installer had a pre-ticked option for Avast Secure Browser and that the app persistently promoted paid products. Review installer selections rather than accepting them automatically.
Bitdefender Antivirus Free: a Windows-focused option
The comparison positions Bitdefender Antivirus Free for readers who want a Windows-only product with low intrusion. It says setup requires a Bitdefender Central account and that its test encountered one upgrade attempt. AV-TEST’s August 2026 listing is for Bitdefender Total Security, not this free edition, so it is not evidence of the free product’s score.
Rank #2
- Dual USB-A & USB-C Bootable Drive – compatible with nearly all Windows PCs, laptops, and tablets (UEFI & Legacy BIOS). Works with Surface devices and all major brands.
- Fully Customizable USB – easily Add, Replace, or Upgrade any compatible bootable ISO app, installer, or utility (clear step-by-step instructions included).
- Complete Windows Repair Toolkit – includes tools to remove viruses, reset passwords, recover lost files, and fix boot errors like BOOTMGR or NTLDR missing.
- Reinstall or Upgrade Windows – perform a clean reinstall of Windows 7 (32bit and 64bit), 10, or 11 (amd64 + arm64) to restore performance and stability. (Windows license not included.). Includes Full Driver Pack – ensures hardware compatibility after installation. Automatically detects and installs drivers for most PCs.
- Premium Hardware & Reliable Support – built with high-quality flash chips for speed and longevity. TECH STORE ON provides responsive customer support within 24 hours.
AVG AntiVirus Free: a candidate for older PCs
The comparison recommends AVG for older Windows versions and hardware. It reports strong lab results, but also more aggressive prompts and pre-ticked installation choices. The AV-TEST August 2026 6/6/6 score applies to AVG Antivirus Free 26.6/26.7 in that test; it does not guarantee the same performance on older or slower hardware.
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Avira Free Security: a bundle with limits
The comparison describes Avira Free Security as including a capped VPN, password manager, updater, and cleaner, while noting that some capabilities are limited or paid. The August 2026 AV-TEST entry is for Avira Internet Security, not Avira Free Security, so do not use that paid edition’s result to judge the free bundle.
Malwarebytes Free: a second-opinion scanner, not a permanent real-time layer
The comparison describes Malwarebytes Free as useful for checking a suspected infection or getting a second opinion. It says real-time protection is not ongoing after day 14. Do not mistake that trial period for permanent free real-time antivirus coverage.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Why the comparison says to skip Kaspersky
The Gizmodo comparison says the available offer it reviewed was a 30-day trial of Kaspersky Standard rather than a permanently free product. It also cites U.S.-specific sales and update restrictions introduced in June 2024, while acknowledging that the restriction it describes does not apply in the same way outside the United States. Those are time- and jurisdiction-sensitive claims, and the comparison’s account is not independently confirmed here against an official regulator. Check current rules and the vendor’s current offer for your country before making a decision. Its stated reason to skip is therefore about free availability and U.S. restrictions, not a claim that the product failed every lab test.
A practical checklist before installing
- Match the edition: confirm whether a score covers the free product or a paid suite.
- Check the test date and operating system: a Windows 11 result from one month is not a guarantee for another Windows version or a later release.
- Look beyond protection: AV-TEST separates protection, performance, and usability; an otherwise strong result may still be a poor fit if it slows your PC or interrupts you.
- Read the free-tier terms: distinguish lasting features from a time-limited trial, capped service, or paid upgrade.
- Inspect setup choices: deselect optional software you do not want, and note whether an account is required.
- Consider your devices and hardware: confirm Windows-version support and evaluate performance on a machine like your own.
For downloads, use the product vendor’s official site or an official app store, and check the installer carefully. If Windows already meets your needs, there is no requirement to add another product simply because it appears on a ranked list.
Do these 3 things before closing this tab:
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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.
