Microsoft Defender Antivirus review
A free Windows antivirus with always-on protection and ransomware controls.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
Microsoft Defender Antivirus is a free, real-time antivirus product built into Windows. It is designed for personal Windows 10 and Windows 11 devices, protecting against viruses, malware, spyware, and other threats without a separately priced subscription. Its core audience is people who want straightforward antivirus protection within the Windows environment, particularly those who do not need coverage beyond Windows.
The protection features cover everyday scanning and threat detection needs. Windows Security provides quick, full, custom, and offline scans, while cloud-delivered protection, automatic sample submission, and tamper protection support the product’s always-on approach. Controlled folder access adds a ransomware-focused safeguard, and Microsoft Defender SmartScreen warns about potentially malicious websites, apps, and downloads. Integration with Windows Firewall, Windows Security, SmartScreen, and OneDrive places the product within Microsoft’s broader Windows ecosystem rather than treating antivirus as a separate application.
Pricing is simple: Microsoft Defender Antivirus is included with Windows at no additional charge. There are no paid tiers described for this product, so buyers are choosing the included Windows protection rather than comparing subscription levels or add-on packages. That makes it a sensible fit for individuals seeking free antivirus coverage on Windows devices and who value built-in controls such as offline scanning, tamper protection, and Controlled folder access. It is less suitable for households or organizations that need antivirus coverage across platforms, since its supported platform scope is Windows 10 and Windows 11. Buyers seeking a separately priced, multi-platform product should consider an alternative with that coverage.
Microsoft Defender Antivirus pros and cons
- Where it wins
- Always-on protection with quick, full, custom, and offline scans
- Controlled folder access adds ransomware-focused protection
- SmartScreen and Windows Firewall integration extend Windows protection
- Where it doesn't
- Works on Windows 10 and Windows 11 devices only
- Focused on antivirus rather than a broader standalone security suite
- Designed for Windows devices instead of multi-platform coverage
Microsoft Defender Antivirus fact sheet, pricing and score →
Advertiser disclosure: iTechGuides is reader-supported. Vendors can pay for top positions in our rankings and for a place on other products' pages, and we may earn a commission when you click some links. Bought places stand at the number bought; this page and our disclosure say so. Paying vendors may get a fuller, more detailed review from our editors, and that review can change their score. How we rank.
Last updated · How we research and update