The best free antivirus 2016

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The best free antivirus software

You need antivirus – that's not in question – but you don't have to pay, as this list of our top ten free antivirus packages shows. Bear in mind (and this should come as no surprise) free antivirus packages aren't just given to you out of kindness. The vast majority exist as adverts for their bigger siblings, as companies do their best to sell you upgraded versions with more features and 'enhanced' protection. However, the free packages should provide all the virus protection you actually need. The paid editions give you firewalls, additional integrations and other gimmicks, but each of the packages we've listed here will help you detect and eradicate any potential virus threats.

We've used the findings of expert virus lab AV-TEST to evaluate the true effectiveness of their virus protection, but that's only half the story. These things need to be running all the time, and if they're annoying or hit your system resources too hard you'll have them uninstalled in a flash. So, on with the evaluation.

Smart and well designed, with excellent detection rates, Avira is our pick of the bunch

1. Avira Free Antivirus

Fast, effective and free - the best antivirus software money can't buy

took the top spot on our previous free antivirus roundup, and here it is again. Yes, AV-TEST's results show it to have a micron less protection than the likes of AVG, but it's the slickest, cleanest and least system intensive antivirus package going. It's almost as if the programmers sat down to determine exactly what users would want out of an antivirus package and somehow stumbled on the correct answer: something that isn't in your face every two seconds and doesn't slow your PC to a halt just by existing.

So hooray for Avira. It doesn't even install a host of other packages (including a secure browser, VPN and safesearch plugin) by default, although they're there if you want them.

It's not the glossiest package, and the install process is a bit pre-emptive, with Windows 10 repeatedly shouting at us to update Avira before it had even finished making its way onto our test machine, but we're inclined to blame Microsoft for the latter glitch. Overall, brilliant.

Free antivirus protection with bonus features including mobile scans

2. AVG AntiVirus Free

Superb virus protection packaged in a super-clear interface

Even though AVG Antivirus Free's virus protection is wrapped in AVG Zen – essentially a large advert designed to encourage you to install all of AVG's products on all the PCs in your home – we won't hesitate to recommend it.

AV-TEST gave AVG AntiVirus a 100% rating for its protection against zero-day attacks during its May-June 2016 testing, for a start. It's reasonably quick to scan after the first initial pass, and the interface – ignoring the Zen bit of it – is super-clear and easy to use. Combine it with the mobile app and you can set it to scan and disinfect a machine without having to be close to it, which is a feature you won't know you need until it's too late.

There are a few downsides. We're not super-fond, for example, of the level of permissions that AVG's Web TuneUp extension asks for – everything from 'read and change all your data on the websites you visit' to forcing your start page to AVG's own Yahoo-powered search engine – but that's an optional component.

A lightweight antivirus suite, Panda Free Antivirus leaves the heavy computing to its cloud servers

3. Panda Free Antivirus 2016

Cloud-based protection for your PC with automatic USB vaccination

Although Panda claims to be the world's lightest antivirus – offloading much of the processing work that would normally be done by your PC to the cloud – we found it to be slightly slower than Avira in our tests, and AV-TEST agreed. It's also right on the industry average in terms of virus detection, sitting at around the 98% mark for zero-day attacks and a hair under 100% for established threats.

Those are good numbers, and Panda is good software – providing you remember to deny it permission to hijack your browser's home page and search facility upon installing.

Its process monitor is very useful, it scans quite quickly, and it's simple enough in its presentation for even the most technophobic user to find their way around. Switch on its automatic USB vaccination to ensure you won't get a nasty infection when you insert something you shouldn't into one of your ports.

Comodo Free Antivirus blocks internet access for all software not on its whitelist by default

4. Comodo Free Antivirus

Serious security software for Windows, Comodo pulls no punches

This is among the hardest-nosed antivirus packages out there, built as it is from Comodo's serious systems administration background. Comodo Free Antivirus features a 'default deny' mode, which essentially blocks every single program that's not on its whitelist – if you let something through and your machine becomes infected, it's going to be your fault.

There's cloud scanning, so it theoretically keeps up with the latest found threats and automatically updates all users based on the newest discoveries, and indeed Comodo scored a perfect 100% against AV-TEST's barrage of zero-day threats, but its historical protection lags behind somewhat at just over 97%.

While Comodo has a sharp design all its own, we'd also say it was something of a mess, unleashing window upon window on your machine and not really shutting up.

You certainly know when you have it installed. At least it includes a game mode, automatically dialling back on its actions when you need maximum performance from your machine.

Avast does an admirable job of protecting your PC, but isn't the lightest security program around

5. Avast Free Antivirus

A solid security suite, but one with a slightly tarnished record

Avast is in the process of buying AVG. We're not entirely sure at this point which of the two will survive – it's possible that both will continue operation, of course – so be careful putting your eggs in either basket at this point.

Avast Free Antivirus, in particular, worries us a little. Earlier in 2016 the Chromium-based browser it includes by default (Avast SafeZone) was found to have a serious security vulnerability not present in Chromium, so the supposed 'World's Most Secure Browser®' turned out to not be so hot. Avast patched the vulnerability immediately following its discovery, but that's poor form.

Its actual antivirus portion isn't awful. It's cleanly presented and performed reasonably well under the stress of AV-TEST's heavy punishment, and even includes a built-in LastPass-esque password manager, which is a great extra feature.

While it's heavier on the system than some, it didn't make our test machine noticeably more sluggish. Even that browser, if you trust it, is absolutely fine. But do you?

Security expert ZoneAlarm has bundled a virus scanner with its latest firewall, and it's not half bad

6. ZoneAlarm Free Antivirus + Firewall

Effective security protection from the grandfather of firewalls

Back in the dark past, when computers were beige and the internet was young, ZoneAlarm was the leading free firewall. It's therefore no surprise that ZoneAlarm Free Antivirus includes a firewall by default – a rare feature among its ilk. It's a big plus, at least if you're not competent in using Windows' own firewall; it's easy to configure and offers interesting insights into the traffic coming to and from your PC. You might even find the things it deflects quite worrying.

Unfortunately AV-TEST hasn't performed an evaluation of ZoneAlarm's antivirus portion – seamlessly integrated with that firewall – for over a year, meaning we can't offer any great confidence in it, though the June 2015 assessment did at least paint it in a flattering light.

The antivirus signatures are being maintained and the software still updated, though, so don't discount it – if you feel the need for a tried and tested firewall alongside your virus protection, this is a competent choice.

Immunet works alongside your regular antivirus software, and employs the collective experience of all its users

7. Immunet AntiVirus

A cloud-based supplement to your main security software

Here's something of an odd one; Immunet is a tiny cloud-based AV solution that's designed to run either independently or alongside your existing antivirus software. The former option isn't, perhaps, the best one; AV-TEST offers no indication as to its effectiveness, and Immunet's reputation – while strengthening in recent years – isn't that of an AV marvel.

That said, as an accompaniment to a known strong solution, we can see no reason not to at least give Immunet a shot. It's all based on collective immunity, meaning the more people use it and report back with threats, the stronger its protection becomes. Like a vaccine for your PC.

There was no noticeable slowdown on our test machine when running it alongside Avira, although in real terms it's going to hammer your CPU a little when scanning. It's also, if such a thing matters to you, almost comically ugly.

360 Total Security rolls several antivirus engines into one free package, but has a reputation for overselling its capabilities

8. Qihoo 360 Total Security Essentials

More virus-scanning engines than its rivals, but not necessarily merrier

Rolling in on a huge wave of bombast – over 52 billion threats thwarted in 2014! – comes Qihoo's 360 Total Security Essentials, which we presume is mainly getting its figures from the third-party engines it uses to scan your PC. Both Bitdefender (the default) and Avira (which should be the default) are on board, and 360 provides a couple of its own engines on top.

Predictably this results in a package which eats more system resources than the rest here, which scans quite slowly, but which passes AV-TEST's 0-day and widespread virus tests with flying colours.

Nevertheless, we'd opt for the simplicity of Avira every time – Qihoo has, in the past, been accused of cheating AV testing to appear more powerful than it truly is, which puts a big trust-shaped cat amongst the virus pigeons.

Its virus database is up to date, but Bitdefender's core engine is starting to show its age

9. Bitdefender Antivirus Free Edition

Still updated regularly, but no longer at the cutting edge

While it comes with a strong brand behind it, Bitdefender Antivirus Free Edition strikes us as something of an afterthought these days – you have to look hard to find it, and the company's own site still crows about its compatibility with the brand-new Windows 8. Indeed, the core software hasn't been updated since 2013, though its virus definitions are at least kept up to speed.

To its credit, Bitdefender Antivirus Free Edition is at least unobtrusive, tucking itself away in the system tray by default and bringing up minimal popups. It's not the fastest, however, and we don't have total faith in its ability to spot every single virus or modern threat.

It's also worth looking at Bitdefender 60-Second Virus Scanner, a tiny app that's worth keeping on a USB stick. If you're foolish enough to run a machine without AV, it'll at least warn you quickly if there's something untoward on board.

Windows' built-in protection might not offer the best detection rates, but it makes minimal use of your system resources and steps neatly aside when you install a third-party security tool

10. Windows Defender

Not as effective as most third-party tools, but quiet and unobtrusive

Every new Windows installation includes Defender by default – if yours doesn't have it, grab Microsoft Security Essentials – so why bother installing third-party protection? A glance at AV-TEST's results regarding Windows Defender's efficacy at defending against the newest zero-day threats tells the story: the May test on its Windows 8 incarnation showed that it caught just 92.1% of nasties. That's just not high enough considering its claims of cloud-based protection, however strong it may be against widespread threats.

To its credit, Defender gets on with the job and stays out of the way, protecting new installations handily. And when it comes time to install something serious, Defender ducks out gracefully – you don't need to uninstall or disable it, it just… goes.

It's simple, with the clearest interface of any package here, but it's also simplistic. So while we appreciate Microsoft's efforts to secure its operating system directly, there's a reason there's still a third-party antivirus market.