Begin with the protection already installed
Start with Windows Defender on an up-to-date Windows 10 or 11 PC. It provides real-time protection without another subscription, and published results from AV-TEST and AV-Comparatives let you check how it performed in the latest test cycle. Malwarebytes Free adds an on-demand second opinion, but it does not replace real-time protection on its free tier. Mac users have a different set of built-in protections, covered below.
Built-in protection covers more than it used to
Windows Defender still carries an old reputation as a placeholder. Current protection should be judged from published lab results and the features enabled on the machine, not from how the product performed a decade ago.
AV-TEST scores antivirus products across protection, performance, and usability, while AV-Comparatives publishes separate real-world protection and performance reports. Results change between cycles. Check the current reports if a lab score is central to your decision rather than relying on an undated claim in a roundup.
Paid suites increasingly sell bundles: VPN access, password management, identity monitoring, family controls, and support. Pay for one when you need that bundle or central management. If malware scanning is the only requirement, compare the current lab results and feature list before assuming the subscription improves protection. For account security, see our free password managers guide.
Four free protection options by platform
1. Microsoft Defender Antivirus: built into Windows
Microsoft Defender Antivirus provides the primary malware protection in Windows 10 and 11. It runs through the Windows Security app alongside Windows Firewall, SmartScreen, and optional controlled folder access. Microsoft’s Windows Security documentation explains which component handles each job.
The built-in stack provides real-time and manual malware scans, cloud-delivered protection, firewall controls, reputation checks, and an offline scan. It does not bundle a consumer VPN or password manager. Some controls, including ransomware folder protection, must be configured rather than assumed to be active.
Published lab results change between test cycles. Use the current AV-TEST Windows results and AV-Comparatives consumer tests if detection or performance results determine your choice.
For an up-to-date personal Windows PC, leave Defender enabled unless another real-time antivirus replaces it. Security intelligence and engine updates arrive through Windows Update, so an unsupported or unpatched Windows installation changes this recommendation.
2. Malwarebytes Free: best on-demand second-opinion scanner
Malwarebytes Free is an on-demand cleanup tool for Windows and macOS. It scans for malware, spyware, adware, and potentially unwanted programs, but ongoing real-time protection requires a paid plan. Use it after suspicious behavior or as a second-opinion scan rather than installing it as a second real-time engine.
Platform names need context here. Malwarebytes offers an Android malware scanner, while its iOS app focuses on ad blocking, malicious-site protection, and suspicious-text filtering. Apple does not allow an iOS app to scan the operating system or other apps for malware. Malwarebytes documents the distinction on its free product page and in its iOS scanning explanation.
This option fits Windows or Mac users who want a manual cleanup scan alongside the protection already running on the computer.
3. Avast Free Antivirus: feature-rich but with privacy trade-offs worth knowing
Avast Free Antivirus offers real-time file, behavior, web, and mail shields. Current Windows versions also include core firewall functionality and ransomware protection; advanced firewall controls and other suite features remain paid. Avast’s feature documentation is the reliable place to check which controls are included in the installed product.
Privacy history is the reason it sits below Defender here. In 2024, the US Federal Trade Commission finalized an order that barred Avast from selling or licensing browsing data for advertising and required a $16.5 million payment. Readers should review current telemetry and privacy settings rather than treating an antivirus label as a privacy guarantee.
Choose Avast when its extra web and network controls solve a specific need and you accept that history. Do not install it solely because a longer feature list appears more protective.
4. AVG AntiVirus Free: same engine as Avast, different interface
AVG AntiVirus Free is owned by the same parent company as Avast (Gen Digital) and uses the same underlying antivirus engine. The main differences are the interface, bundled features, and branding.
The free app includes real-time malware detection, core shields, Smart Scan, and ransomware protection. AVG’s current feature FAQ separates those features from paid firewall and advanced email controls. Avoid relying on old comparisons that put all ransomware protection behind a subscription.
AVG shares Avast’s corporate ownership and relevant privacy history. Between the two, compare the current interface and enabled modules on your platform; neither needs to be installed alongside another active real-time antivirus.
5. Bitdefender Antivirus Free: focused Windows protection
Bitdefender Antivirus Free is a Windows-only product with real-time malware protection, basic ransomware protection, phishing defenses, and configurable scans. It has a normal application interface, and Bitdefender documents custom scan scheduling.
The free edition leaves out the broader privacy and device-management tools in Bitdefender’s paid suites. Its current comparison labels the free product “basic protection, Windows only.” Mac, Android, and iOS users need a different Bitdefender product or another option from this guide.
Choose it when you want a focused third-party Windows antivirus and do not need a bundled VPN, cross-platform subscription, or advanced suite controls. Performance varies by device and test cycle, so this guide does not promise a particular memory or speed result.
Compare real-time protection and scans
| Tool | Real-time protection | Platforms | Main trade-off |
|---|---|---|---|
| Windows Defender | ✅ Yes | Windows only | Best kept updated via Windows Update |
| Malwarebytes Free | ⚠️ Manual cleanup on computers | Windows, Mac; different mobile features | No real-time computer protection on free |
| Avast Free | ✅ Yes | Win, Mac, Android, iOS | Data collection history |
| AVG Free | ✅ Yes | Win, Mac, Android, iOS | Same parent company as Avast |
| Bitdefender Free | ✅ Yes | Windows only | Focused feature set |
Antivirus protection on a Mac
macOS faces a different mix of threats from Windows. Apple’s XProtect, Gatekeeper, and app sandbox provide the built-in layer. Malwarebytes Free can add manual cleanup scans, while Avast and AVG offer free Mac antivirus products. Bitdefender Antivirus Free in this comparison is Windows-only.
When paid antivirus makes sense
On a current Windows 11 machine with updates enabled, a separate paid antivirus is usually unnecessary for basic malware protection. Paid suites become useful for VPN access, identity monitoring, family controls, support, or multi-device administration. If none of those solve a problem you have, compare current lab reports before replacing Defender. For files stored online, see our free cloud storage comparison.
A free password manager addresses password reuse, which antivirus cannot fix. If you run a website or server, free security audit tools can check exposed ports and security headers outside an endpoint antivirus product’s scope.
A paid suite can replace several separate subscriptions
A paid security suite can make sense when you want a VPN, identity monitoring, support, or management across several devices under one subscription. Compare the exact platform coverage and renewal price before replacing free tools that already meet your needs.
Want full VPN protection?
NordVPN has an independently audited no-logs policy, covers up to 10 devices on one account, and includes Threat Protection to block malware and trackers.
Get NordVPN →Use one real-time scanner
Keep Windows Defender if Windows is current and you do not need a paid suite’s extras. Add Malwarebytes Free for manual second-opinion scans after suspicious activity. On a Mac, start with Apple’s built-in protections and add a separate scanner only when your risk or support needs justify it. Whatever you choose, recheck current lab results and product limits because both change.
