Free Antivirus Software: 5 Virus Scanners Compared

Our pick

Avast One Free Antivirus

Well-known virus protection with real-time scanning, but heavy on paid-version ads

Free foreverReal-time protection includedLimited featuresWith upgrade prompts

The free part of Avast One can be used with no time limit and includes real-time virus protection, scam website blocking, a cleanup tool and data breach monitoring. The VPN is only a 60-day trial in the free version. Firewall, webcam protection and automatic software updates are reserved for the paid edition.

Avast One Free Antivirus checks files, downloads, web traffic and email in the background and uses a behavior monitor and a ransomware shield to protect selected folders. Scheduled scans and a do-not-disturb mode for full-screen applications are included. In the June 2026 AV-TEST round the Avast engine got full marks, and in the AV-Comparatives test (March 2026) its online detection was 98.7%.

The price of the free version is advertising: a Go Premium button is always visible, a driver update panel cannot be hidden, and extra software is pre-selected during installation. On privacy, Avast has a past: until 2020 its subsidiary Jumpshot sold browsing data. That business has been shut down, and you can choose in the settings which data is shared.

Screenshot of the Avast One Free Antivirus user interface

Pro: Real-time, web and email protection in the free version
Pro: Ransomware shield for selected folders
Pro: Full marks in AV-TEST (June 2026)
Pro: Runs on Windows, macOS, Android and iOS
Pro: Do-not-disturb mode for games and full-screen apps
Pro: Can be used without an account
Con: Constant upgrade prompts and a driver panel that cannot be hidden
Con: Extra software pre-selected during installation
Con: Firewall, webcam protection and software updater are paid-only
Con: VPN is a 60-day trial only
Con: Privacy history from the Jumpshot scandal

Platform: Windows, macOS, Android, iOS
Our rating: 8.6 / 10

Visit website – Avast One Free Antivirus

AVG AntiVirus Free

Same technology as Avast, simpler layout, but also with upgrade pressure

Free foreverReal-time protection includedLimited featuresWith upgrade prompts

AVG AntiVirus Free can be used with no time limit and offers real-time protection for files, web and email. The advanced firewall protection, webcam protection and automatic app updates are reserved for the paid edition. Like Avast, the software belongs to Gen Digital and uses the same detection engine.

AVG AntiVirus Free protects Windows 7 to 11 as well as macOS, Android and iOS. The Windows version offers file and web protection, email scanning, scheduled custom scans and a file shredder. In AV-TEST (June 2026) AVG got full marks like Avast, and its AV-Comparatives results (March 2026) are identical because both products use the same engine.

The free version is funded by advertising here too: during installation two boxes are pre-ticked (browser install and default browser), a Go Premium button is always visible, and discount banners and trial offers appear. On privacy the same applies as for Avast: until 2020 the group sold browsing data through Jumpshot and has since shut that business down.

Screenshot of the AVG AntiVirus Free user interface

Pro: Real-time protection in the free version
Pro: Full marks in AV-TEST (June 2026)
Pro: Windows 7 to 11, plus macOS, Android and iOS
Pro: Scheduled scans and file shredder
Pro: Cleaner layout than Avast One
Con: Advanced firewall, webcam protection and app updates are paid-only
Con: Two pre-ticked boxes during installation
Con: Permanent upgrade button, discount banners and trial offers
Con: Same engine as Avast, so no added variety
Con: Privacy history of the group

Platform: Windows, macOS, Android, iOS
Our rating: 8.4 / 10

Visit website – AVG AntiVirus Free

Microsoft Defender Antivirus

Already built into Windows, ad-free and with nothing extra to install

Free foreverReal-time protection includedBuilt into Windows

Microsoft Defender Antivirus (formerly Windows Defender, now part of Windows Security) is a standard component of Windows 10 and 11. It costs nothing extra, runs in the background and gets its updates through Windows Update. If you install another antivirus, Defender switches itself off. For Mac and Android, Defender is only available as part of a paid Microsoft 365 subscription.

Defender protects in real time by default, includes a cloud connection and works with the Windows SmartScreen filter, which blocks dangerous websites and downloads. There are no ads and no upgrade buttons. In AV-TEST (June 2026) Defender scored 6, 5.5 and 6 out of 6, and in AV-Comparatives (March 2026) its online detection was 98.1% with only 3 false alarms. Offline, the figure was clearly lower at 89.2%.

The limits are in the extras: there is no VPN, password manager or parental control, and no monitoring for data breaches. According to PC-WELT, Defender is usually enough for an average home user who is mostly online. The price is the telemetry that Windows sends anyway.

Pro: Already included in Windows 10 and 11, no download needed
Pro: Real-time protection on by default
Pro: No ads and no upgrade buttons
Pro: Strong lab results with few false alarms
Pro: No second vendor and no extra account
Pro: Automatic updates through Windows Update
Con: Windows only; Mac and Android require a paid Microsoft 365 subscription
Con: Offline detection clearly weaker than online in the test
Con: No VPN, password manager or parental controls
Con: No data breach monitoring
Con: Windows telemetry is sent along

Platform: Windows 10, Windows 11
Our rating: 8.3 / 10

Visit website – Microsoft Defender Antivirus

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Bitdefender Antivirus Free

Lean free virus protection with real-time scanning and few ads

Free foreverReal-time protection includedLimited features

According to several tests, Bitdefender Antivirus Free is a Windows version that stays free with real-time protection, web protection and basic ransomware protection. Firewall, VPN, password manager, parental controls and data breach monitoring are reserved for the paid edition, as are all other platforms such as macOS, Android and iOS.

Bitdefender Antivirus Free uses the same scan engine as the vendor's paid products and protects Windows 10 and 11 in real time. Features include malware, web and ransomware protection and a manual USB scan. The Bitdefender engine reached 97.6% in AV-Comparatives (March 2026) with 4 false alarms. These results mostly refer to the paid products and apply to the free version only approximately.

In everyday use the free version stands out for showing few ads: one test saw an upgrade dialog at sign-in and a small upgrade button in the title bar. In return there are hardly any settings, and there is no firewall of its own, so you rely on the Windows firewall.

Platform: Windows 10, Windows 11
Our rating: 8.1 / 10

Screenshot of the Bitdefender Antivirus Free user interface

Pro: Real-time, web and ransomware protection for free
Pro: Same scan engine as the paid products
Pro: Few ads compared with Avast and AVG
Pro: Lean and without bundled software
Pro: Strong detection results of the engine in lab tests
Con: Windows 10 and 11 only
Con: Hardly any settings
Con: No firewall of its own, no VPN and no password manager
Con: Setup may require a Bitdefender account
Con: Lab results mostly refer to the paid products

Visit website – Bitdefender Antivirus Free

Avira Free Security

Free security package with real-time protection and extras, but tight limits

Free foreverReal-time protection includedLimited featuresWith upgrade prompts

Avira Free Security can be used with no time limit and without an account. It includes real-time virus protection, a browser protection extension, a basic password manager, a file shredder and a VPN. The VPN is capped at 500 MB per month. Firewall, unlimited VPN and automatic app and driver updates are reserved for the paid edition.

Avira Free Security uses cloud-based detection with behavior monitoring and works without registration, so there is no device limit. It also offers a basic password manager, a file shredder, a check for outdated software and drivers, and a free browser extension that blocked about 90% of phishing URLs and malicious downloads in one test. In AV-TEST (June 2026) Avira scored 6, 4.5 and 6 out of 6.

The limits are in the extras: system-wide web protection and fixing most findings from the Smart Scan are paid, and with 500 MB a month the VPN is more of a trial. The interface often promotes the paid edition and a 60-day trial. If you only use the normal quick scans, you will notice this less.

Platform: Windows, macOS, Android, iOS
Our rating: 7.8 / 10