Windows 11 already comes with Microsoft Defender built-in, but many users still prefer a dedicated third-party antivirus for extra protection, better malware detection, or additional features.
Below, we’ll look at the best options available — including AhnLab, Avast, Avira, Bitdefender, and 360 Total Security — so you can decide which one works best for you.
1. Bitdefender Antivirus Free Edition
Best for lightweight, powerful protection
Bitdefender continues to rank high in independent lab tests thanks to its excellent malware detection rates and minimal impact on system performance.
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✅ Strong real-time protection
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✅ Excellent phishing and fraud detection
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✅ Runs quietly in the background
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❌ Limited customization (you’ll need the paid version for advanced features)
If you want a “set it and forget it” antivirus that just works, Bitdefender Free is a top choice.
2. Avast Free Antivirus
Best for extra features
Avast offers more than just antivirus — its free version also includes a password manager, Wi-Fi security scanner, and basic ransomware protection.
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✅ Packed with useful extras
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✅ Good malware detection
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✅ Easy-to-use interface
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❌ Some features locked behind upsells
Avast is ideal if you want more than just basic antivirus without paying for premium.
3. Avira Free Security
Best for privacy-focused users
Avira Free comes with antivirus, a basic VPN (500 MB/month), and performance optimization tools.
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✅ Reliable malware detection
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✅ VPN included (with limits)
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✅ Lightweight on system resources
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❌ Frequent upgrade prompts
For users who care about both security and privacy, Avira is a great free option.
4. AhnLab V3 Lite
Best lightweight antivirus from Asia now gaining global traction
While not as well-known in the U.S., AhnLab is a respected South Korean cybersecurity company. Its free antivirus (V3 Lite) provides solid protection without being resource-heavy.
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✅ Lightweight and fast
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✅ Clean, simple interface
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✅ Decent protection against common threats
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❌ Limited features compared to larger brands
If you want something minimal that just protects your PC without bloat, AhnLab is worth trying.
5. 360 Total Security
Best all-in-one system care + antivirus
360 Total Security combines antivirus with system cleanup and optimization tools. It uses multiple engines (including Avira and Bitdefender) to detect threats.
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✅ Multiple antivirus engines
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✅ Includes system cleaning and speed-up tools
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✅ Free and feature-rich
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❌ Contains ads and can feel bloated
Great if you want both PC security and performance tools in a single free package.
Which Free Antivirus Should You Choose in 2025?
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Want the strongest detection with no hassle? → Bitdefender Free
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Need extra tools and features? → Avast Free
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Care about privacy & a bonus VPN? → Avira Free
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Prefer something lightweight and simple? → AhnLab V3 Lite
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Want antivirus + PC optimization in one? → 360 Total Security
No matter which you choose, all these options are completely free and compatible with Windows 11 in 2025. Just make sure to install only one antivirus at a time to avoid conflicts.
Explore other helpful tools in our Windows utilities section.
