An on-demand antivirus is an antivirus program that you run only when you want it to. It does not protect you from viruses and other malware all the time, like a traditional antivirus program.

So what’s the point? These types of anti-malware tools are great if you think you have a virus or other malware, but the antivirus program you’re currently using didn’t catch it. Sometimes, a really nasty malware is preventing your installed antivirus program from working properly, in which case one of these tools can come in handy.

Below you will find a complete list of the very best free on-demand virus scanners available. Many of these programs even come in a portable version, meaning no installation is required!

Malwarebytes is one of the most popular free on-demand virus scanners. In our experience, it has found more malicious files than any other virus scanner we have used.