antivirus product · Microsoft Corporation

Microsoft Defender Antivirus

The antivirus built into Windows, run from the Windows Security app with a firewall, ransomware folders and an offline scan.

88/100

#2 of 10 antivirus products
Facts checked 8 Oct 2026

In short

Microsoft Defender Antivirus is built into Windows and gives real-time protection with no separate purchase^1,2.
Controlled folder access stops unknown apps from changing files in protected folders such as Documents and Pictures².
Microsoft Defender Offline restarts the PC and scans it without loading Windows².
SmartScreen in Microsoft Edge warns about phishing sites and tech support scams⁴.
The Microsoft Defender app for Mac, Android and iOS needs a Microsoft 365 Personal or Family subscription⁵.

Microsoft Defender suits anyone with a Windows PC who wants solid protection without buying anything. Windows Security adds a firewall, controlled folder access and an offline scan, all built in^2,3. The catch is that SmartScreen's website checks are documented for Microsoft Edge, and the apps for other systems need a Microsoft 365 subscription^4,5.

Best for: Windows users who want protection without buying anything.

Where the points come from

Independent lab results38 of 45

Protection features25 of 25

Price20 of 20

Refunds and security5 of 10

Independent lab results 38 of 45 points

Rule	What is published	Points
AV-TEST score	17.5 of 18AV-TEST, July and August 2026: 17.5 of 18 (Microsoft Defender Antivirus (Consumer) 4.18).⁸	12 / 15
AV-Comparatives award	ADVANCED+AV-Comparatives, February to May 2026: ADVANCED+ (Microsoft).⁹	15 / 15
AV-Comparatives protection rate	99%AV-Comparatives, February to May 2026: 99% (Microsoft).⁹	11 / 15

Protection features 25 of 25 points

Rule	What is published	Points
Systems covered	Windows, macOS, Android, iOSBuilt into Windows; the Defender app for Mac, Android and iOS comes with Microsoft 365 Personal or Family^1,5.	8 / 8
Firewall	YesThe Windows Security app shows and manages Windows Firewall³.	5 / 5
Ransomware protection	YesControlled folder access blocks unknown apps from changing files in protected folders².	5 / 5
Rescue or offline scan	YesMicrosoft Defender Offline scans after a restart, without loading Windows².	4 / 4
Browser protection	YesSmartScreen warns about phishing and malicious sites in Microsoft Edge⁴.	3 / 3

Price 20 of 20 points

Rule	What is published	Points
Free edition with real-time protection	YesBuilt into Windows with real-time protection^1,2.	8 / 8
First-year price	$0Built into Windows; nothing to buy¹.	6 / 6
Price from the second year	$0No subscription; it comes with Windows¹.	6 / 6

Refunds and security 5 of 10 points

Rule	What is published	Points
30-day refund	Not publishedNot applicable: there is nothing to buy.	0 / 5
SOC 2 Type II or ISO 27001	YesMicrosoft names ISO/IEC 27001 certification for its cloud services, including Microsoft Defender for Endpoint⁷.	5 / 5

The rule behind each line: how we score antivirus products.

Plans and prices

As the vendor lists them, before tax. Prices are in US dollars unless the plan shows euros; the points use US dollars, with euros converted at the ECB rate.

Plan	Price as listed	Per month	Notes
Microsoft Defender Antivirus (Windows Security)Windows PCs	Free¹	$0	Built into Windows

The Microsoft Defender app for Mac, Android and iOS comes with a Microsoft 365 Personal or Family subscription⁵.

Strengths

Built into Windows, with real-time protection^1,2.
Controlled folder access protects Documents, Pictures, Videos, Music and Desktop from untrusted apps².
Microsoft Defender Offline scans in the Windows Recovery Environment².
Windows Firewall is managed from the same app³.

Limits

SmartScreen's website and download checks are documented for Microsoft Edge⁴.
Phishing protection for your Windows password is not available in Windows 10⁴.
The Defender app for Mac, Android and iOS needs a Microsoft 365 Personal or Family subscription⁵.
The Defender app's VPN feature was removed on February 28, 2025⁶.

Other antivirus products

1
BitdefenderPeople who want a capable free edition or a cheap first year
94/100
$24.99/yrfirst-year price
3
KasperskyBuyers outside the United States who want a firewall in the cheapest plan
84/100
$49.99/yrfirst-year price
4
AvastPeople who want a free Windows antivirus with real-time protection
83/100
$49.08/yrfirst-year price
5
NortonPeople who want a firewall and cloud backup in one paid app
77/100
$29.99/yrfirst-year price

Microsoft Defender Antivirus vs Bitdefender · Microsoft Defender Antivirus vs Kaspersky · All 10 antivirus products

Sources

Stay protected with the Windows Security app, Microsoft Support. Accessed 8 Oct 2026.
Virus and Threat Protection in the Windows Security App, Microsoft Support. Accessed 8 Oct 2026.
Firewall and network protection in the Windows Security app, Microsoft Support. Accessed 8 Oct 2026.
App & browser control in the Windows Security App, Microsoft Support. Accessed 8 Oct 2026.
Getting started with Microsoft Defender, Microsoft Support. Accessed 8 Oct 2026.
End of support-Privacy protection (VPN) in Microsoft Defender for individuals, Microsoft Support. Accessed 8 Oct 2026.
ISO/IEC 27001:2013 Information Security Management Standards, Microsoft Learn. Accessed 8 Oct 2026.
Test antivirus software for Windows 11 - August 2026, AV-TEST. Accessed 8 Oct 2026.
Real-World Protection Test February-May 2026, AV-Comparatives. Accessed 8 Oct 2026.

Website: support.microsoft.com/en-us/windows/security/windows-security/stay-protected-with-the-windows-security-app · Markdown version · We are not affiliated with Microsoft Corporation.