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Best Free Antivirus 2024: The top cyber security on a budget

It’s long since been established that dependable antivirus software is essential for any digital device, but what if you’re tied to a strict budget? Our round-up of the best free antivirus software has you covered.

While there’s no denying that a paid antivirus software will always be the way to go in terms of building a truly comprehensive level of cyber security across all of your key devices, the need for antivirus protection of any kind if so pertinent that there are plenty of companies out there that offer a free tier for basic level defence.

In fact, there is now so much free antivirus software out there that the space has become quite competitive, making it harder to know which ones are actually worth signing up for. After all, the last thing anyone wants is to find out their antivirus software isn’t up to task until a nasty virus sweeps their computer. Even with free software, things should never get to that point, which is exactly where we come in.

Trusted Reviews has been testing the best antivirus software available for years, and we apply those same rigorous techniques to our free antivirus reviews. This includes verifying their potency against various malware, as well as deep diving into the variety of features offered.

No matter which pick from this list strikes your fancy, you can rest assured that it has been put through its paces by one of our testers and is therefore recommended for use. If you want to beef up your digital security beyond antivirus software then you can also check out our rundown of the best VPN and best free VPN.

It’s also worth mentioning that if your current laptop is starting to show its age and throwing an antivirus into the mix might slow it to a halt then it could be time to take a look at current crop of best laptops.

How we test

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.

Avast One Essential

Best overall antivirus
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  • Works on Windows 7 & 8.1
  • Very accurate
  • Ransomware defence


  • More false positives than some rivals

Avast One Essential has ascended to the top of the list as the very best free antivirus of 2024, and that’s for one key reason: it prevented 100% of malware in the latest string of tests. It did see a few false positives, suggesting it may be a little too militant, but it’s still great to see a third-party antivirus post even more impressive performance results than Microsoft Defender Antivirus, which is built into Windows 11 by default.

That said, the performance difference isn’t big enough to make an upgrade essential if you’re using Windows 11. Avast One Essential becomes more useful if you’re using an outdated operating system.

Avast One Essential is partly funded by advertising and partner promotion. It has a number of useful features, carrying out real-time scanning of potential threats, as well as on-demand and scheduled system scans. It even has a built-in do not disturb mode that’s automatically activated whenever you run a fullscreen application.

You will get far more features from paid-for services such as McAfee Plus Advanced and Norton 360, but if you don’t want to spend a penny while still seeing top-grade security, then Avast One Essential is our top recommendation.

Reviewer: K.G. Orphanides
Full review: Avast Free Antivirus Review

Microsoft Defender Antivirus

Best overall free antivirus
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  • Excellent integrated Windows 10/11 interface
  • Excellent malware protection
  • No need to install anything
  • Free


  • 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.

Reviewer: K.G. Orphanides
Full review: Microsoft Defender Antivirus Review

Avira Free Security

A mediocre antivirus with lots of 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.

Reviewer: K.G. Orphanides
Full review: Avira Free Security Review


Is free antivirus safe?

Yes, all of the antivirus options listed are safe to use.

What is the difference between free antivirus software and paid antivirus?

Both forms of antivirus can detect and block malware, but paid-for options can unlock additional features such as VPNs and advanced parental controls.

Which antivirus is free forever?

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.

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Today, we have millions of users a month from around the world, and assess more than 1,000 products a year.

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