Malwarebytes
Windows anti-malware tool, 411.1 MB, served from the official Malwarebytes host
Free antivirus for PC: Windows tools sorted by type
The free antivirus tools for Windows here do quite different jobs, so grouping them by type works better than ranking them. Malwarebytes, ESET Security and BitDefender Agent are general protection programs. ClamAV is an open-source engine, and ClamWin Free Antivirus is a free scanner that supports Windows versions from 98 to 10. AdwCleaner targets adware and junkware, and Emsisoft Emergency Kit is a portable scanner that needs no installation.
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None of these tools is ad-free, and every one is free to use. File sizes range from the 9.2 MB AdwCleaner to the 411.1 MB Malwarebytes. Update dates vary a lot too: Malwarebytes was updated on October 2, 2026, while ClamWin's last update was June 7, 2021. Check that date before choosing a tool for daily use.
Apps in this category
ClamAV
Free open-source Windows antivirus engine; 1.5.4 patches several CVEs
ClamWin Free Antivirus
Free GPL antivirus for Windows 98 through 10, built on ClamAV, v0.103.2.1
AdwCleaner
Free 9.2 MB Malwarebytes tool that removes adware and junkware on Windows
BitDefender Agent
Free Bitdefender antivirus installer for Windows 10, 13.5 MB, official download
ESET Security
Light Windows antivirus using ESET LiveGrid, downloaded from ESET's own server
Emsisoft Emergency Kit
Portable dual-engine malware scanner from Emsisoft, free, no install needed
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Top 5 picks
Malwarebytes
Malwarebytes is the general protection pick of the group. It covers malware, ransomware and malicious websites. Version 5.7.2.358 was updated on October 2, 2026, the most recent date among the seven, and at 411.1 MB it is the largest of the listed tools. It is proprietary software and free to use.
ClamAV
ClamAV represents the open-source engine type. Cisco Systems publishes it under GPL-2.0, and it detects trojans, viruses and malware. Version 1.5.4 was updated on August 7, 2026, at 214.1 MB. As an engine, it is more a building block than a finished desktop program.
AdwCleaner
AdwCleaner covers the adware type. It finds and removes unwanted programs and junkware. Version 8.8.1.639 was updated on February 20, 2026, and at 9.2 MB it is the smallest download on this page. Malwarebytes is the developer, and the license is freeware.
Emsisoft Emergency Kit
Emsisoft Emergency Kit is the portable second-opinion type. It requires no installation and uses two scanning engines to clean up infected machines, and the listing positions it for emergency removal. Version 2025.7.0.12683 was updated on March 23, 2026. The download is 328.6 MB and the license is freeware.
BitDefender Agent
BitDefender Agent represents the compact vendor-backed type. It is a free edition designed to protect a Windows PC. Version 26.0.1.233 is 13.5 MB, but the last update was November 18, 2022. That age is worth weighing against the 2026 updates on several other entries.
Questions and answers
Which type of free antivirus fits everyday use?
The types are not ranked against each other. General protection programs are the closest match to everyday use: Malwarebytes, BitDefender Agent and ESET Security, which is 85.6 MB and was updated on August 24, 2026. Compare update dates before deciding.
Is ClamWin still current?
ClamWin is at version 0.103.2.1, last updated June 7, 2021. It supports Windows 10 down to Windows 98. ClamAV, by contrast, is at version 1.5.4 with an August 7, 2026 update.
Can I run two of these tools together?
Emsisoft Emergency Kit is a portable scanner for second-opinion checks, with no installation needed. Check each publisher's guidance before running two tools side by side.
Related categories
Best-of lists
Start by deciding what job you need done. For ongoing protection, pick one general program and look at its update date first. ESET Security at version 19.2.10.0 and Malwarebytes both show 2026 updates. Portable and cleanup tools fill other roles. Emsisoft Emergency Kit runs without installation, and AdwCleaner is only 9.2 MB, so keeping either on hand costs little disk space. Download sizes range from 9.2 MB to 411.1 MB, which matters on older machines or slow connections.