Avast Antivirus Free review: Our favourite free solution

If you don’t want to pay for malware protection, there are several free options. The most obvious is what’s already built into Windows 10, but big names such as Bitdefender and Kaspersky also offer free versions. In our view, however, Avast’s is the best free offering, providing strong protection and a feature set that goes beyond its rivals.

It’s not quite impeccable: during AV-Comparatives’ malware tests, Avast dropped the ball just once. If our protection scores were extended to three decimal places, it would come away with an overall rating of 99.998%. That’s still an excellent result, and better than you can expect from the free editions of Avira or Malwarebytes – or indeed Microsoft Defender. There’s a good range of scanning and notification options too, meaning you can tweak Avast’s behaviour to suit your preferences.

Avast also missed out on a clean sheet when it came to false positives, erroneously sounding the alarm three times during the test. Again, though, that’s better than Windows’ built-in scanner fared, and a mile ahead of paid-for suites from Malwarebytes and Norton.

Beyond regular malware-blocking duties, Avast wins credit for its breadth of additional protections. As soon as you install it, Avast inspects your browser for suspect extensions, and scans your installed applications to spot any that might be in need of security updates. If you want Avast to automatically fetch and apply the patches, you’ll need to upgrade to the Premium package, but the warnings alone provide valuable insight that other packages miss.

Then there’s the Wi-Fi scanner, which sniffs out all other devices on your wireless network to help you spot any intruders and warns you if it detects any insecure passwords or other vulnerabilities that could be exploited by an attacker. Again, the software can’t fix such issues, but it can at least indicate where you need to shore up your defences.

The Ransomware Shield, meanwhile, does the same job as Windows’ built-in Controlled Folder Access feature, but in a more user-friendly way. When an untrusted program tries to write to a protected location, Avast immediately flings up a requester that lets you block or approve the app with a click, rather than requiring you to rummage around in the settings.

Finally, the Hack Alert feature extends protection outside of your own network by monitoring releases of leaked or hacked data from third-party servers. If any credentials connected to your email address are found to have been compromised then you’ll be warned immediately, giving you a chance to change your password before someone else does. Have I Been Pwned offers the same free service, but it’s handy to have the function built into your security software – and it works continually in the background.

As a rule, the catch with free software is the upsell. We were irked but not entirely shocked when, even before the program had launched for the first time, the installer popped up a warning that the firewall and phishing protection modules weren’t enabled. Predictably enough, clicking “Resolve all” takes you to a purchasing page, where you’re invited to pay up for Avast Premium Security.

Yet it’s hard to feel too annoyed by this. The premium subscription isn’t offensively expensive – the two-year option works out to £23 per annum – and once you start using the program proper, there’s very little in the way of pushy marketing. Yes, the interface is laden with buttons for features that aren’t included in this free edition, but they’re all clearly marked with little orange padlock icons, so you never feel deceived. The worst we can really say is that all the icons clutter up the front-end a bit.

The other potential area of concern is performance, and carrying out a full scan of our test folder proved a slow business, dragging on for more than a quarter of an hour. In everyday use, however, you’re likely to rely upon on-access scanning, and here Avast ticks along smoothly. Across AV-Test and AV-Comparatives’ tests, system speed with Avast Antivirus Free averaged 91.9% of “bare metal” performance, stacking up incredibly well against competitors.

When you download a free antivirus package, you know you’re not going to get the kitchen sink. Even so, Avast brings together a broad range of useful security tools – and when it comes to the job of stopping viruses, it performs very creditably. Perhaps most pleasingly, while the advertising element is certainly there, we never found it obnoxious. All of this makes Avast our favourite free solution.