Best free antivirus 2015: Your definitive list of the best free internet security software

Want to know what the best free antivirus package is? Read our round-up to find out

They say you don’t get something for nothing, but when it comes to protecting your PC against online threats that's not necessarily the case. There are plenty of completely free antivirus tools around that can automatically block malicious code, and actively scan the files on your PC to ensure you’re not unknowingly harbouring something nasty. In this article we bring you the best free antivirus packages of 2015 to keep your PC safe.

For many, the default option is Microsoft Security Essentials (you may know this as Windows Defender - it was renamed in Windows 8). Depending on the version of Windows you’re running, this will either come preinstalled or will be offered to you through Windows Update.

As antivirus programs go, Security Essentials is as straightforward as things get: most of the time you won’t even know it’s there, and it has very little impact on the responsiveness of your system.

In our independent tests, however, it allowed more than the odd bit of malware to slip through the cracks – so it’s worth considering picking a third-party alternative.

Third party tools will almost certainly offer better protection than the default Windows offering, but that's not the only advantage they provide. They should also deliver more features, such as browser cleanup tools, software updaters, and even rescue disk creation tools for when things get really bad.

Best free antivirus 2015: packages compared

One well known option is AVG AntiVirus Free, which has been providing free virus protection since the 1990s. The modern AVG client actively detects and blocks viruses, and also integrates with your browser to warn you away from known dangerous websites.

On low-power hardware, however, its scanner has a noticeable impact on the responsiveness of the system it's running on. Although it’s free to download and use, the sheer amount of in-program advertising is irritating. And malware protection isn't the best around, either.

Our favourite free antivirus tool of 2015, however, remains Avast Free Antivirus - the same as last year. In our tests this package gained not only an impressively high protection rating, but it also allows most legitimate applications to install, even obscure ones. You also get a host of secondary tools, including a silent mode to prevent pop-ups during gaming and a hardened browser to protect inexperienced users.

Avast is also light on resources and shouldn’t noticeably slow your PC down; and although, like AVG, the front-end includes advertisements for paid-for products, these are much less plaintive. For all these reasons, Avast Free Antivirus 2015 is our recommended free antivirus package.

Best free antivirus 2015

1. Avast Free Antivirus 2015

Avast Free Antivirus 2015 review - main UI

The best of the free security suites, Avast's likeable offering delivers effective virus protection in a lightweight yet well-equipped package.

Read the full Avast Free Antivirus 2015 review here.

2. AVG Antivirus FREE 2015

AVG Antivirus Free (2015) review - main interface

A free antivirus package with more adverts than useful features, but it’s a better bet than Microsoft Security Essentials and its protection and false positives ratings have been increasing recently.

Read the full AVG Antivirus FREE 2015 review here.

3. Microsoft Security Essentials

Microsoft Security Essentials 2015 review - interface

Security Essentials covers only the bare basics of malware protection, and allowed alarmingly high percentage of attacks to succeed in our tests. If you value the safety and security of your PC, you'll install a third party package to boost your protection levels.

Read the full Microsoft Security Essentials (2015) review here.

Other packages

Panda Free Antivirus

Additional testing by Dennis technology Labs carried out during January and March 2015 expanded the tests to include Panda Free Antivirus. The results indicate it’s an improvement over Microsoft Security Essentials, but that it can’t match AVG or Avast for performance.

Panda’s malware protection score isn’t bad at 90%, nor is its false positives rating, which is 94%. However, its closest rival, AVG has been steadily improving of late and performs significantly better, particularly when it comes to false positives. For the ultimate in protection, meanwhile, you might want to consider Avast or 360 Safe (see below) instead.

360 Safe

Employing twin antivirus engines and a friendly, intuitive interface, when tested last year 360 Safe provided excellent protection, gaining a stonking 99% score.

Read the full 360 Safe review here.

How the software is tested

Each package's core anti-malware features are tested at the state-of-the-art facilities of Dennis Technology Labs. Rather than artificially infecting the target systems, they are set up in an environment that mimics how our PCs become infected in the wild, to get an accurate picture of how each security package fends off malware in real-world situations.

We look at whether the package provides protection, and also how it handle each threat. The resulting data informs a protection rating of up to 100%. Meanwhile, we also install legitimate software to see what the security packages block and where they prompt for use r intervention, factoring in the obscurity or otherwise of the application. We award a second score for false positives, where 100% represents a perfect record.

After formal testing, we run through each package to check its other features and get a feel for its usability and its burden on system resources. We measure the latter by monitoring RAM and CPU consumption over the course of basic scan, also timing how long these scans take to complete. All this information is factored into the final, Overall star rating you'll see at the top of each review.

Best Free Antivirus: Test Results

Overall score*

Jan-March 2015

Oct-Dec 2014

July-Sept 2014

Avast

97%

93%

95%

360 Safe

Not tested

Not tested

90%

AVG

89%

85%

78%

Panda Free Antivirus

78%

Not tested

Not tested

Microsoft

73%

66%

68%

*The overall score is a weighted average of protection and false positives scores.

Malware protection scores*

Jan-March 2015

Oct-Dec 2014

July-Sept 2014

Avast

98%

93%

97%

360 Safe

Not tested

Not tested

99%

AVG

93%

84%

76%

Panda Free Antivirus

90%

Not tested

Not tested

Microsoft

68%

56%

59%

* The malware protection score rates how many threats a security package catches and how well it deals with them.

False positive scores*

Jan-March 2015

Oct-Dec 2014

July-Sept 2014

Avast

99%

97%

97%

360 Safe

Not tested

Not tested

90%

AVG

100%

100%

99%

Panda Free Antivirus

94%

Not tested

Not tested

Microsoft

100%

100%

100%

* The false positives score indicates how well security packages handle legitimate software. A higher score is better.

All results provided by Dennis Technology Labs.

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