In 2026, which is the best free antivirus for Windows?

Is it a good idea to drop Windows Defender?

Having an antivirus on your Windows computer is so important that, since 2006, Microsoft has integrated antispyware into Windows Vista, which will become an antivirus, under the name Windows Defender.

Historic! A built-in antivirus in Windows Vista! Photo credit: © securiteinfo.com

From now on, competition in the antivirus market will be fierce. What's the point of buying an antivirus when Windows Defender comes bundled with Windows? Free and 100% compatible with Windows, since it was developed by Microsoft, Windows Defender has a big advantage over some of its competitors. Some of them, such as PC Tools and F-Prot, which were very popular in the 90s and 2000s, will disappear altogether.

« Should we trust Microsoft Windows Defender blindly? »

In 2026, the question remains. Should we blindly trust Microsoft Windows Defender for our cybersecurity? Are there free alternatives to Microsoft's antivirus? And are these alternatives better than Windows Defender? That's what we're going to find out through a full-scale test.

Details of our antivirus comparison in 2026

The comparison is not sponsored. We have absolutely nothing to gain by saying that one antivirus is less good than another. If you're familiar with SecuriteInfo.com, you'll know that we don't resell any hardware or software products, in order to maintain our independence. We sell our own products, and we don't care about other brands.
We used 100,000 pieces of malware, in all formats, extracted directly from our malware collection. What these 100,000 pieces of malware have in common is that they were all collected in 2025. So they're fairly recent malware, not 20-year-old antiques.
Our comparison focuses solely on malware detection. All other functions are ignored, such as firewall, network detection, obsolete file cleanup, software updates, etc. The aim of our test is not to give you the most complete solution, but the one that detects as much malware as possible.
We ran the tests on Windows 11, with the malware on a network drive in read-only mode over a 2.5 Gb/s network.
As we ourselves sell our “additional signatures for ClamAV anvirus” product, we didn't include ourselves in the comparison. And with good reason: since we supply the malware, we have a de facto 100% detection rate with our additional signatures.

Antivirus comparison results in 2026

Here are the results of our tests:

1st : Avast One version 25.12.10659.0: 79635 malwares / 100000, i.e. 79.63% detection.
2nd : Bitdefender Antivirus Free 27.0.55.298: 75898 / 100000, i.e. 75.89% detection.
3rd : Windows Defender 4.18.24090.11: 37175 malwares / 100000, i.e. 37.17%. It is very slow and took more than 3 days to scan the 100000 files.
4th : Comodo antivirus 12.2.2.8012: 10058 malwares / 100000, i.e. 10.05% detection. It is very slow and took more than 24 hours to scan the 100000 files.

« 1st: Avast One 79.63% detection rate »

The losers

Here are the antivirus products we tested, but found unsatisfactory:

Avira Free Security 1.1.112.2751: Like last year, it stopped at 34372 files out of 100000. It detected 29694 malwares out of 34372, i.e. 86.39% detection. We do not know why it did not scan everything. We clearly specified in the scan configuration that all files should be scanned.
Panda Dome 23.0.0: 1838 malwares / 31678, i.e. 5.80% detection. It froze during the scan and did not finish scanning the 100000 files.
Kaspersky: impossible to perform the test, as it took an enormous amount of time to scan each file on the network drive. According to the scan estimation, it would have taken more than a month to scan all the files.
Trend Micro HouseCall and MalwareByte 5.4.5.226 cannot scan a network drive. Wake up! It’s 2026! Network drives have existed for a long time!

Conclusion

Antivirus protection is the most important protection for your computer. The variety of malware is incredibly large: viruses, ransomwares, exploits, spywares, information-leak software, remote control software, rootkits, ... The detection rate of these threats is therefore the top priority of all priorities. We do not care if your antivirus does not include a firewall or does not clean obsolete files, as long as it detects as many malicious programs as possible!

But now, we can state that on Windows it is preferable to install Avast One, even without going Premium, rather than keeping Windows Defender.

We also note that no free antivirus exceeds the 80% detection threshold.

« No free antivirus exceeds the 80% detection threshold. »

This year, we note that Panda and Comodo should be avoided at all costs if cybersecurity matters to you. We strongly advise against their use.
Our comparison nevertheless has limitations, notably that results may vary from one month to another, maybe even from one week to another. However, we have decided to repeat the antivirus test next year, which will allow us to observe the evolution of each product. Let us hope that competition will make Avast shake and that the overall malware detection rate will be higher across all products. See you in January 2027 for an update of our antivirus comparison.