Best Free Antivirus Software for Windows and Mac (2025 Edition)

In 2025, cybersecurity threats are more advanced than ever. From AI-generated phishing emails to crypto-jacking malware, both Windows and macOS users need a solid layer of defense. Fortunately, you don’t have to pay for strong protection — several free antivirus programs now include AI-driven threat detection, ransomware defense, and privacy tools once found only in premium suites. This guide walks you through the best free antivirus software for Windows and Mac in 2025, how to install them safely, and what makes each unique.

Why You Still Need Antivirus in 2025

Even though both Windows and macOS have built-in protections, modern attacks have evolved beyond simple viruses. Threats now include:

• Phishing emails powered by generative AI.
• Fake browser extensions and crypto miners.
• Fileless malware that hides in memory.
• Cross-platform trojans targeting both Windows and Mac.
  A good antivirus adds an intelligent layer of defense, scanning in real-time and blocking malicious files or suspicious network activity before any damage happens.

1) Bitdefender Antivirus Free

Platform: Windows, macOS
Why it stands out: Lightweight and consistently ranked among the top performers by AV-Test and AV-Comparatives.
Bitdefender Free offers powerful, AI-based malware detection with almost zero performance impact. It quietly monitors your system in real-time, blocks phishing sites, and automatically updates definitions in the background.
Pros: Excellent malware detection, silent operation, low CPU usage.
Cons: Limited customization and extra tools.
Best for: Users who want strong protection that “just works.”

2) Kaspersky Free Security

Platform: Windows, macOS
Kaspersky remains a strong contender thanks to its proven detection rate and transparent cloud-based scanning. The free version includes real-time protection, anti-phishing filters, and automatic updates. It also includes a free VPN (300MB/day) and password manager trial.
Pros: High detection accuracy, bonus privacy tools, user-friendly interface.
Cons: Some advanced features require internet access.
Best for: Users seeking comprehensive protection with a few privacy extras.

3) Microsoft Defender (Built-in for Windows 11)

Platform: Windows
Microsoft Defender has matured into a full-fledged antivirus engine with cloud-based intelligence and ransomware protection. It runs automatically in Windows 11, requiring no installation or manual updates. The system integrates SmartScreen filtering to block malicious websites and attachments.
Pros: Built-in, no cost, minimal system impact.
Cons: Lacks advanced utilities like VPN or dark web monitoring.
Best for: Everyday users who want simple, reliable protection.

4) Avast One Essentials

Platform: Windows, macOS
Avast’s free suite offers real-time scanning, ransomware shields, and web protection powered by global threat intelligence. It also detects unsafe Wi-Fi networks and browser add-ons. The new 2025 update includes AI-based heuristic scanning for zero-day threats.
Pros: Packed with features; good for general home use.
Cons: Occasional upgrade prompts; slightly heavy on older PCs.
Best for: Users who want an all-in-one tool with extra privacy and performance utilities.

5) AVG AntiVirus Free

Platform: Windows, macOS
AVG shares the same detection engine as Avast but with a simpler, less resource-heavy design. It provides real-time protection against malware, phishing, and spyware, and includes an email shield to block malicious attachments.
Pros: Lightweight, easy to use, effective web protection.
Cons: Some features hidden behind the paid version.
Best for: Beginners and users on older computers.

6) Avira Free Security

Platform: Windows, macOS
Avira Free Security combines antivirus protection with privacy tools such as a built-in VPN (500MB/month), software updater, and browser safety add-ons. Its AI-driven protection monitors files and websites in real-time, and the system optimizer improves startup times.
Pros: Fast, private, great all-around value.
Cons: Limited VPN bandwidth; frequent upgrade ads.
Best for: Privacy-conscious users looking for more than just malware protection.

7) Malwarebytes Free (On-Demand Scanner)

Platform: Windows, macOS
Malwarebytes is the go-to tool for removing hidden threats missed by other antiviruses. While its free version doesn’t include real-time protection, it’s perfect for cleaning up adware, spyware, and potentially unwanted programs (PUPs).
Pros: Excellent malware removal, lightweight, fast scanning.
Cons: No automatic protection in free version.
Best for: Secondary defense or system cleanup.

Best Free Antivirus for macOS (2025)

macOS users are no longer immune to modern threats. Adware, browser hijackers, and cryptocurrency miners increasingly target Macs. The following free solutions are top picks:

• Bitdefender Free for Mac: Minimal impact, cloud-based scanning, great for general users.
• Avast One for Mac: Excellent phishing and web protection with regular updates.
• Malwarebytes Free for Mac: Ideal for cleaning adware and unwanted browser extensions.

How to Stay Secure Beyond Antivirus

Even with strong antivirus software, your habits matter most:

• Keep software updated: Outdated apps and drivers are common attack points.
• Use a password manager: Avoid reusing passwords across sites.
• Enable 2FA: Add a second layer for logins whenever possible.
• Be cautious with downloads: Only install apps from verified publishers.
• Backup regularly: Cloud or offline backups protect against ransomware.

Choosing the Right Antivirus in 2025

If you’re on Windows 11 and want simplicity, Microsoft Defender is enough for daily use. For stronger, multi-layered protection, Bitdefender Free or Kaspersky Free are great upgrades. Mac users should rely on Bitdefender Free or Malwarebytes Free for lightweight yet effective defense.
If you need extra features like a VPN, password manager, or privacy cleaner, Avira Free or Avast One Essentials are worth trying.

Final Thoughts

The best antivirus is the one you’ll actually use and keep updated. In 2025, free antivirus tools are powerful enough for most home users thanks to integrated AI threat detection and cloud protection. For maximum safety, combine one of these free tools with smart online habits, strong passwords, and regular backups.

FAQ

Which free antivirus is best overall in 2025?
Bitdefender Free delivers the best mix of accuracy, performance, and simplicity on both Windows and Mac.

Is Windows Defender enough for Windows 11?
Yes, for most users it’s sufficient. Pair it with Malwarebytes Free for deeper scans and cleanup.

Do Macs need antivirus?
Yes. macOS is more secure by design, but it’s not immune. Phishing, adware, and data-stealing malware are increasingly targeting Mac users.

Which antivirus uses AI for threat detection?
Bitdefender, Avast, and Kaspersky all use AI-driven behavior analysis to stop zero-day and polymorphic malware before it spreads.