For many people using Windows 11 at home, Microsoft Defender is a capable built-in antivirus and a reasonable starting point. A third-party suite is optional—not automatically more protective—and makes sense when its specific extra features or independently measured tradeoffs fit your needs.
Do you need antivirus if you use Windows Security?
Windows 11 includes Microsoft Defender Antivirus. Microsoft says it continually monitors for malware and other threats and downloads updates automatically. Its protections include real-time, behavior-based, heuristic and cloud-delivered detection. For a home PC that stays updated and is used with care, that makes Defender a practical baseline without buying another antivirus product. Microsoft’s Defender Antivirus overview describes the product and its protection capabilities.
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Windows Security also includes protections beyond the antivirus engine. Microsoft describes Network protection as a Windows 11 feature that can help protect third-party browsers and processes from phishing sites, malware, tech-support scams and malicious downloads. These broader Windows security features should not be confused with features unique to a separately purchased antivirus suite.
Free tools Windows power users keep installed
One-click scans. No signup required.
What do independent test results say?
Recent AV-TEST results do not support a blanket claim that paid antivirus always detects more malware than Defender. In its July–August 2026 comparison of 15 home-user security products on Windows 11, AV-TEST used default settings and current publicly available versions, assessing protection, performance and usability on scales of up to six points each. Results apply to the named products and that test period, not every PC or future release. See AV-TEST’s Windows home-user comparison.
#1 Best Overall
- 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.
| Product and tested version | Protection | Performance | Usability |
|---|---|---|---|
| Microsoft Defender Antivirus (Consumer) 4.18 | 6/6 | 5.5/6 | 6/6 |
| Bitdefender Total Security 27.0 | 6/6 | 6/6 | 6/6 |
| ESET Security Ultimate 19.1 & 19.2 | 6/6 | 6/6 | 6/6 |
| Norton 360 26.6 & 26.7 | 6/6 | 6/6 | 6/6 |
The scores show small measured differences, not a universal winner: Defender received 5.5/6 for performance while the three listed third-party products received 6/6 in that comparison. AV-TEST’s separate May–June 2026 review of Defender Antivirus Consumer 4.18 on Windows 11 Professional 64-bit recorded 100% results in both months for its zero-day real-world threats and its recent widespread malware reference set. Those are outcomes for the test samples and dates, not a promise to stop every threat. View the detailed Defender test results.
When is a third-party antivirus worth choosing?
Consider another product if you have a concrete reason to prefer its additional features, interface or tested performance. Compare the product version currently offered with the versions in independent tests, and weigh protection, performance, usability and false positives alongside the features you would actually use. A lab score is useful evidence, but it cannot establish that a particular suite is the right fit for every household.
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.
Performance findings depend on the test setup as well as the product. AV-Comparatives’ April 2026 low-end performance report used an up-to-date 64-bit Windows 11 system and tested activities such as copying files, archiving, installing and launching applications, downloading and browsing. The report says its results apply to the named versions and 64-bit systems; it is not a universal prediction of how a suite will feel on every PC. Read the AV-Comparatives performance-test scope.
Current prices, renewal terms, plan limits and device coverage are not established by these test results. Check those details for your country and the exact product edition before purchasing rather than assuming a high-scoring product is the best value.
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.
How Defender and another antivirus work together
Microsoft says Defender Antivirus turns off automatically when a compatible non-Microsoft antivirus app is installed and active, and turns back on if that app is uninstalled. Do not try to run two active antivirus engines at once; use Windows’ documented handoff instead. Microsoft documents this behavior in its Defender overview.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.How to scan or check protection in Windows Security
Windows Security offers quick, full, custom and offline scans. To choose one, open Windows Security, select Virus & threat protection, then choose Quick scan or open Scan options for a full, custom or Microsoft Defender Offline scan. An offline scan restarts into the Windows Recovery Environment and can scan without an internet connection. Microsoft warns that files opened or downloaded while real-time protection is off are not scanned until protection is turned back on. See Microsoft’s Windows Security scan guidance.
Quick Recap
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.
Rank #4
- 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.
A practical decision checklist
- Stay with Defender if you want the included Windows 11 baseline and do not have a particular need for a separate suite.
- Compare third-party products if a named extra feature or product-specific tradeoff matters to you; use recent tests as one input, not a guarantee.
- Check purchase details such as edition, renewal price, device coverage and regional availability directly with the seller.
- Keep the whole PC safer by updating Windows and other software and taking care with links and downloads. Antivirus is one part of security, not a substitute for those habits.
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.
