Every Windows 10 and Windows 11 PC ships with Microsoft Defender Antivirus switched on, so the real question is not whether you have protection but whether you need more of it. This guide compares what Defender includes with what paid suites such as Kaspersky and McAfee typically add, so you can decide on features rather than fear.
Is Microsoft Defender enough for Windows 11?
For many home users, Microsoft Defender Antivirus, together with the firewall, SmartScreen and regular Windows updates, provides solid everyday protection at no extra cost; a paid suite becomes worth considering when you want extras Defender does not bundle, such as a VPN, a password manager, parental controls or protection across several platforms.
| Feature | Built into Windows 11 | Typical paid suite |
|---|---|---|
| Real-time antivirus and malware scans | Yes, Microsoft Defender Antivirus | Yes, vendor's own engine |
| Firewall | Yes, Windows Firewall | Often its own firewall or management layer |
| Dangerous app and website warnings | Yes, Microsoft Defender SmartScreen | Yes, web protection and anti-phishing |
| Ransomware folder protection | Yes, controlled folder access (turn it on first) | Usually included |
| VPN | No | Included in many suites |
| Password manager | No dedicated vault in Windows Security | Included in many suites |
| Parental controls | Family options links to Microsoft family tools | Built into many suites |
| Mac and Android coverage | Not part of Windows | Depends on the product |
The honest answer depends on how you use your PC. Someone who installs software only from known sources, keeps Windows updated and uses a separate password manager may be well covered by Defender alone, while a family sharing devices may value a suite that manages everything in one place.
What does Microsoft Defender include in Windows Security?
The Windows Security app combines Microsoft Defender Antivirus with account protection, Windows Firewall, SmartScreen app and browser control, device security features such as core isolation, TPM and Secure Boot status, a device health report, family options and a protection history, all built into Windows 10 and Windows 11.
Microsoft's Windows Security app overview describes each area. Virus and threat protection runs real-time scanning and manual scans and receives updates to detect new threats, while the Ransomware protection page offers controlled folder access, which you switch on yourself, and file recovery through OneDrive.
One advanced nuance: some protections depend on your hardware and edition. Device security features such as core isolation rely on TPM and virtualisation support, which is why Windows 11's hardware requirements, covered in our guide to TPM 2.0 and Secure Boot, also matter for security.
What do paid antivirus suites add?
Paid suites build on core malware protection with extra tools in one subscription: commonly a VPN, a password manager, safe banking or browsing protection, an encrypted file vault, webcam and microphone protection, parental controls, identity or data-breach monitoring and apps for Windows, Mac and Android, managed from a single account.
The exact feature list varies by product and edition, so compare the one you are considering rather than the brand name. For example, the McAfee Total Protection licence we sell lists a VPN, password manager, encrypted storage and identity protection, while Kaspersky's suites list safe banking, privacy tools and parental controls.
What we commonly see is buyers choosing a suite for one specific extra, usually the VPN or parental controls, rather than for the antivirus engine itself. If that describes you, check that the feature you want is in the exact edition and device count you buy.
How can I compare antivirus protection fairly?
Compare protection using independent test laboratories such as AV-TEST and AV-Comparatives, which regularly test antivirus products, including Microsoft Defender, for malware detection, false positives and performance impact; read their latest reports yourself rather than relying on marketing claims or older rankings, because results change between test rounds.
When reading a report, look at three things together: protection rate, false alarms and system slowdown. A product that blocks everything but flags many safe files, or slows the PC noticeably, may be less useful in daily life than its headline score suggests.
Check the test date and product version too. Antivirus engines update constantly, so a result from two years ago tells you little about the version you would install in October 2026.
Can I buy and use Kaspersky in the United States?
No, not through new purchases: the US Commerce Department's Bureau of Industry and Security barred Kaspersky from entering new agreements with US persons from 20 July 2024, and from 29 September 2024 prohibited signature and software updates and the resale of Kaspersky antivirus software in the United States or to US persons.
The details are on the BIS Kaspersky information page, which also links to removal guidance for individuals. Without updates, antivirus software loses its ability to recognise new threats, which is the practical reason US users were advised to move to an alternative.
This restriction is specific to the United States. Availability and rules in other countries vary and can change, so check the position in your own country before buying. If Kaspersky is available and permitted where you live, our Kaspersky Total Security licence is one option to compare.
Can I run Microsoft Defender and another antivirus together?
You should not run two real-time antivirus engines at once; on Windows 10 and Windows 11, Microsoft Defender Antivirus switches itself to disabled mode automatically when you install another antivirus product, and Microsoft warns that two products providing active protection at the same time can conflict and affect performance.
Microsoft's Defender compatibility documentation also explains the reverse. If the third-party product expires, is uninstalled or stops providing real-time protection, Defender can switch itself back on automatically.
This cause and effect matters when a paid subscription lapses. An expired suite that still sits on the PC may leave you with outdated protection, so either renew it or uninstall it fully and let Defender take over again. Running a one-off on-demand scanner occasionally is a different case from two real-time engines.
How do I choose between Defender, Kaspersky and McAfee?
Start with how many devices and platforms you need to cover, which extras you would actually use, and the rules in your country; if Defender plus good habits covers you, extra software may add little, but if you want a VPN, password manager or parental controls across Windows and Mac, a suite may be simpler.
- Single Windows PC, careful user: Defender with Windows updates switched on is a reasonable baseline.
- Family with children: consider a suite with parental controls, or Microsoft Family Safety.
- Mac user: Defender Antivirus is part of Windows, so Mac users need a separate product such as McAfee Premium Security for Mac.
- Frequent public Wi-Fi use: a suite with a VPN may suit you.
- Located in the United States: choose a product other than Kaspersky, as explained above.
Whatever you choose, the basics do much of the work: keep Windows and apps updated, use genuine software, and avoid cracked tools and "pre-activated" installers, which frequently disable security features. Our guide to pre-activated Windows ISO risks explains why.
Frequently asked questions
Do I need antivirus on Windows 11?
Windows 11 already includes Microsoft Defender Antivirus, switched on by default, so every PC has baseline antivirus protection. Whether you need additional software depends on the extras you want, such as a VPN, password manager or parental controls, and on how many devices and platforms you want to protect.
Is Microsoft Defender free?
Yes. Microsoft Defender Antivirus is part of Windows 10 and Windows 11 at no extra cost. Separately, Microsoft offers a Microsoft Defender app for Microsoft 365 Personal and Family subscribers, covering more platforms; Microsoft retired its privacy protection VPN feature from that app on 28 February 2025.
Does installing McAfee or Kaspersky turn off Defender?
Yes, on Windows 10 and Windows 11 Microsoft Defender Antivirus moves to disabled mode automatically when another antivirus provides real-time protection. If that product expires or is removed, Defender can turn itself back on, so your PC is not left without an active antivirus engine.
Is a Kaspersky licence legal to buy outside the US?
The US restriction applies to transactions in the United States and with US persons. Rules elsewhere differ by country and can change, so check local guidance before buying. This is general information, not legal advice; your national cybersecurity agency is the right place to confirm the current position.
Do I need antivirus on a Mac?
Microsoft Defender Antivirus in Windows Security does not cover Macs. Mac options include the Microsoft Defender app for Microsoft 365 Personal and Family subscribers, or a Mac-compatible suite with web protection, a VPN or a password manager; check which macOS versions the product supports before buying.