Regardless of how you use your PC and what type it is, we’d always advise opting for a decent antivirus software. However, with so many subscriptions to splurge on, it can feel like an annoying additional purchase.
Fortunately there’s a good amount of free antivirus software available that does an admirable job at keeping your PC safe from malware. While there’s no denying that a paid antivirus software will always boast more features and provide a more comprehensive level of security, a free alternative is a brilliant way to get at least a basic level of protection for your PC.
So, with countless free antivirus software options currently available, it can be difficult to determine which one will actually offer a decent amount of protection. That’s where we come in.
We’ve reviewed a number of free antivirus software and put each one through a rigorous testing process to determine how well they really protect your computer against malware and other cyber threats. We also test any notable and additional features of the software such as health reports, free VPN access, parental controls and more.
Only the top performing free antivirus software has made it into this guide, so rest assured that it has been put through its paces by our team of experts. If you think you might need a bit more oomph then visit our best antivirus guide instead.
Want to tighten your digital security even further? Check out our best VPN and best free VPN lists too.
Otherwise, if your current PC could do with an upgrade then our best laptop guide has our current top-performers for all budgets.
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Learn more about how we test antivirus software
For raw performance against malicious software, we use data from multiple testing houses: AV-Test, SE Labs and AV-Comparatives. Of these tests, we prioritise ‘real-world’ performance, in which antivirus detection engines are exposed to live threats.
We also draw on system performance data captured by AV-Test and we inventory and compare features on an application-by-application basis, highlighting both useful tools and unexpected sticking points in the workflow and interfaces.
Pros
- Works on Windows 7 & 8.1
- Very accurate
- Ransomware defence
Cons
- More false positives than some rivals
Pros
- Excellent integrated Windows 10/11 interface
- Excellent malware protection
- No need to install anything
- Free
Cons
- System impact isn’t as low as you might expect
Pros
- Works on Windows 7 & 8.1
- Includes lots of extra tools
- Effective malware defence
Cons
- Ransomware defence isn’t included
- No silent mode
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Works on Windows 7 & 8.1 -
Very accurate -
Ransomware defence
-
More false positives than some rivals
Avast One Essential is our number one recommendation for free antivirus, as its tests by AV-Test, AV Comparatives and SELabs showcased Avast’s ability to prevent up to 100% of malware. Avast’s free antivirus outperformed even Microsoft Defender Antivirus – an app built into Windows 11.
Avast One Essential also presented a few false positive results, suggesting the antivirus might even be a tad too militant at times. The stronger performance might not be enough to necessitate upgrading from Microsoft Defender if you’re a Windows 11 user. However, it is a great choice for those using older operating systems no longer supported by Microsoft. This includes Windows 7 and Windows 8.1.
Partly funded by advertising and partner promotion, Avast One Essential is packed with useful features, including real-time and on-demand scans, a gaming mode and a free VPN. Installation is smooth and simple with no guilty tripping for opting for the free version. You also don’t need to create an Avast account, though doing so does allow you to receive alerts if your email address pops up in any breaches.
You’ll get more features and stronger performance from paid VPNs, like McAfee Plus Advanced and Norton 360. However, if you’re looking for a free, third-party antivirus that works on older systems as well as new ones and is as good (if not better) than Microsoft Defender, we’d recommend making Avast your first port of call.
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Excellent integrated Windows 10/11 interface -
Excellent malware protection -
No need to install anything -
Free
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System impact isn’t as low as you might expect
Built into Windows 10 and 11, Microsoft Defender is the one of the most consistently reliable antivirus suites around. It got perfect 100% protection scores in AV-Test’s most recent tests, 99.5% in AV Comparatives’ latest real-world test and 100% in SE Labs’ tests. That’s top-flight performance, although AV-Test did also find that Defender can have a greater impact on system performance than third-party antivirus solutions.
Core anti-malware components include real-time protection and on-demand scans covering everything from quickly checking a folder to a comprehensive offline scan that checks for hard-to-remove threats such as rootkits by scanning the system without booting into Windows. However, scheduled scans have to be set up via Windows Task Scheduler.
As well as virus protection, Defender includes Windows Firewall, parental controls and remote management of your family’s devices, reputation-based site blocking in Edge and application blocking in general, system health reports, and the ability to disable all notifications.
Overall, Microsoft Defender is so good that there’s no real need to go looking for third-party alternatives. But Avast One Essential did see a better performance in the latest tests, while paid-for options will always offer more features.
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Works on Windows 7 & 8.1 -
Includes lots of extra tools -
Effective malware defence
-
Ransomware defence isn’t included -
No silent mode
Avira has a longstanding reputation as a lightweight antivirus suite that’ll run on almost anything. That makes it a good alternative to Microsoft Defender if you’re using a dated version of Windows.
Avira has been a little inconsistent in regards to performance results over the past few years, but it saw fantastic results in the latest round of testing, achieving 100% protection for AV-TEST and SE Labs, and 99.8% for AV Comparatives.
Free users only get access to the real-time protection module, plus scheduled and on-demand scans. If you want the dedicated web, email and ransomware protection modules, you’ll be prompted to subscribe to Avira Prime. Similarly, the free version has no do-not-disturb mode for gaming.
It comes with plenty of other tools for system optimisation, file shredding, and tweaking Windows’ privacy settings, plus a very limited 500MB/month VPN allowance. These are all handy, but can’t quite outshine Microsoft Defender for Windows 10 and 11 users.
FAQs
Yes, all of the antivirus options listed are safe to use.
Both forms of antivirus can detect and block malware, but paid-for options can unlock additional features such as VPNs and advanced parental controls.
Every antivirus listed is free for an unlimited time. But you will need to pay for the premium tier if you want to unlock additional features.
We’ve hailed the Avast One Essential as being the best free antivirus in the UK, thanks to its decent range of features, brilliant performance and support for older systems too.
Test Data
| Avast One Essential | Microsoft Defender Antivirus | Avira Free Security |
|---|
Full Specs
| Avast One Essential Review | Microsoft Defender Antivirus Review | Avira Free Security Review | |
|---|---|---|---|
| Manufacturer | Tronsmart | Microsoft | Tronsmart |
| Size (Dimensions) | x x INCHES | x x INCHES | x x INCHES |
| ASIN | – | – | B00QQU6QHE |
| Release Date | 2021 | 2021 | 2021 |
