Best Alternative to Microsoft Defender Antivirus of 2025

Microsoft Defender keeps millions of users safe as it's the default antivirus software for all Windows machines. This, however, doesn’t mean that users usually don’t reach for a third-party solution that now comes bundled with a plethora of useful tools.

We would argue that Defender is good enough for most users, though if you’re in the camp of proactive internet users, reaching for a more comprehensive solution may be needed.

We have identified the best alternatives to Microsoft Defender, and we will look into why we think it's worth upgrading if you’re looking for an alternative.

Best alternative to Microsoft Defender

Features:

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Avast Free offers a fair amount of features and tools at the free tier. You'll have access to Avast's antivirus, alongside an AI assistant that can help you spot scams and fraud.

By also using the Avast Free Browser, you can add safe browsing, payment protection, and scam protection to the list of features, alongside built-in ad blocking and anti-phishing capabilities.

Even at the free tier, Avast provides password leak notifications that scan the dark web for your credentials and notifies you if they appear in a breach.

The main difference between the two is that Microsoft Defender does include a firewall, which you can only get from Avast if you choose to upgrade. Luckily, the two software can be used together to double up your protection.

Security:

Avast has scored top marks from AV-Test in the latest testing, receiving a score of 6/6 across protection, performance, and usability. As for AV-Comparatives testing, Avast blocked 99.5% of threats but had a fairly high false-positive rate, detecting 15 safe files as malware.

Price:

Both Avast Antivirus Free and Avast Free Browser are both completely free. If you do choose to upgrade your protection, the next step up is Avast Premium Security which adds a firewall, email detection, and a secure sandbox to open risky files.

Best Microsoft Defender alternative for lightweight protection

Features:

There is a reason that Bitdefender Free Antivirus is our pick for the best lightweight alternative to Microsoft Defender - it doesn't have any unnecessary bells and whistles that could impact performance or distract you.

Bitdefender includes the necessities, including its excellent antivirus, safe browsing protection, payment protection, and even throws in scam protection for good measure.

For a free service its quite a good package that has been optimized to minimize its impact on your device. It doesn't have a firewall, but in our testing it did play fairly nicely with the built-in Microsoft Defender firewall, so the two can be used in conjunction to maximize protection.

Security:

Bitdefender has frequently held the top spot for antivirus performance. In AV-Comparatives testing Bitdefender scored an impressive 99.8% malware block rate, with only a mere 3 false positives.

As for AV-Test scores, Bitdefender achieved 6/6 across the board for protection, performance, and usability.

Price:

Bitdefender Antivirus Free is entirely free, and as an added bonus it won't constantly pester your with adverts asking you to upgrade.

The next tier up, Bitdefender Antivirus Plus, costs $24.99 and adds in a firewall, VPN with a 200MB/day cap, and breach notifications for one device.

Best paid Microsoft Defender alternative

Features:

If you truly want to beat the features offered by Microsoft Defender, it might be worth opting for a paid plan - Norton Antivirus Plus specifically.

This plan provides Norton's excellent antivirus protection, plus a firewall, safe browsing and payment protection. Additionally, you will be able to Norton's flagship Genie scam protection tool, with a password manager and 2GB cloud backup thrown in for good measure.

Security:

Norton is one of the best performing antivirus solutions on the market, and for good reason. Norton Antivirus did very well in the latest AV-Comparatives real-world scenarios, detecting 99.5% of the sample threats with 9 false-positives.

As for AV-Test, Norton also scored 6/6 across the board for protection, performance, and usability.

Price:

Norton Antivirus Plus starts off with a 30-day free trial, and then costs $29.99 for the first year, or $2.49 per month. The renewal price does rise to $59.99 after the first year.

Comparison

Check out our guide to the best antivirus software for even more alternatives