The best free alternatives to Microsoft Defender

Installing the best third-party antivirus product not only boosts protection, it also brings some potentially useful features

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When we talk about Microsoft Defender this month, we're talking about the basic out-of-the-box protection that comes with Windows 10 and 11 (not to be confused with the variety of Microsoft's paid-for services by the same name, such as Microsoft Defender for Business). It’s pretty good, but it’s not currently the best free antivirus around in terms of malware detection and accurate assessment of benign but unknown or obscure software.

We're exclusively covering free antivirus software with a real-time protection component here. This rules out popular antivirus tools such as Malwarebytes Free, which only provides on-demand scanning. This can be useful to sit alongside your real-time malware defences, in case you want a second opinion on a suspicious file, for example, but doesn’t meet our requirements that malware protection must be constantly active.