How we test antivirus software

When you download antivirus protection – whether it’s paid-for or free software – you want to feel confident that hordes of internet nasties will be safely locked out of your PC or Mac. That's where we come in.

When we say our test is tough, we mean it. Each package is hit with more than 10,000 samples of malware. We test how effectively the packages work while your PC is offline, as well as online.

The world of cyberthreats never sleeps, so testing just once a year isn’t good enough. We fire new batches of malware at the antivirus software every three months to ensure standards haven’t slipped.

One of our best antivirus software packages will keep your computer as safe as Fort Knox. 

How well will I be protected from malware?

Unlike you, we’re constantly hoping to catch the world’s worst computer bugs. Antivirus programs are designed to block such malicious software, so to test them we need plenty of internet nasties.

Our specialist lab operates what are called ‘honeypots’ – think of these like digital fishing nets designed to capture thousands of strains of murky malware and viruses. We have more than 60 honeypots around the world and these capture up to 400,000 files every day, and up to 146 million over a year. This includes Windows and Android malware, along with the rarer Apple Mac malware. 

We check antivirus programs to ensure they don’t let you pass on infected files to other people, even if the files haven’t been opened by you first.

We also punish packages that pester you with confusing messages and warnings or wrongly zap a file that you actually want to use (known as a ‘false positive’).

And we don’t test just once and say ‘job done’. No, we rerun our full protection assessment every three months to ensure the packages are still doing an effective job. 

Will the antivirus help me avoid scams?

Many security software packages claim to protect you from scam webpages and emails, but do they actually do what they say?

We click on links contained in phishing emails – hoax emails sent in the hope that the recipient will enter confidential information – to see whether the software stops you from proceeding to these dangerous scam websites designed to steal your data or infect your machine.

We throw in a few genuine emails, too, to see whether the software wastes your time by flagging emails and websites that are clearly safe for you to access.

Is the software easy to install and use?

It's all very well for a security software program to pick up every virus and spam email that's out there, but it still needs to be easy to use and unobtrusive.

We look for security software that not only identifies threats, but warns you clearly and talks to you in jargon-free language. Points are deducted for confusing or scaremongering alerts and any ambiguous action that could compromise security.

Before that, we buy and install each security software package on a ‘fresh’ computer, and rate this process, including what is and isn’t included, along with how easy it is to stop the software licence from automatically renewing (and charging you) after it expires.

Plus, we rate the initial software set-up process and first scan, looking to see if it's easy for a beginner to set up properly. Whether it's software that you pay for, or a package vying to be one of our best free antivirus downloads , we'll tell you if it's going to be a breeze to use on your computer.

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Does it include all the features I need?

The main things that separate paid-for and free antivirus software packages are the added extras that come with them. If you’re spending money on your protection, then you’ll want some bells and whistles to sweeten the deal.

So we tell you whether the program you’re eyeing up includes useful features, such as parental controls or a VPN.

If the supposedly premium features aren’t worth the money, we’ll flag that up to you, too. It may be that a free package will meet your needs just as well.

It's also worth noting that some features may be exclusive to Windows versions of antivirus software. If you use a Mac, have a look at our dedicated best Mac antivirus. 

Will it slow down my computer?

Virus protection scans should operate silently and discreetly in the background while you get on with using your computer.

The worst programs will frustratingly reduce your system to a crawl while they carry out their routine virus checks.

We undertake a range of everyday tasks on our test computer while the software operates, and compare this with when the antivirus package hadn't been installed.   

Any antivirus package that means it takes an age to open a web browser or save files will lose marks in this test, known as our ‘use of resources’ assessment.

Should I install it?

We consistently test a range of antivirus every year, both free and paid-for software. Our expert tests reveal how each software performs when we throw a myriad of threats at them, and their ability to resolve those threat. 

We combine the results of all these assessments when we calculate the total test score, so that you can find the software that combines the best of protection, ease-of-use and added features.

A premium is put on the package’s antivirus credentials, since it should be brilliant at keeping your PC or Mac free from malware.

The final score breaks down as follows and doesn’t take price into account. Free downloads are judged on the same criteria as paid-for packages:

• Protection (65%)
• Ease of use (25%)
• Use of resources (10%)

Best Buy antivirus

Only the very best antivirus software is awarded our Best Buy badge. A Windows antivirus package needs to achieve a total test score of 83% or above. Mac packages need to have a score of 78% or higher. 

Great Value antivirus

Our Great Value badge signposts products, appliances, gadgets and tech that are excellent deals. When it comes to antivirus software, our Great Value badge is assigned only to free software that does its core job very well and is also easy to use. 

 Free Windows software has to achieve a test score of 80% or higher to receive our Great Value badge. Free Mac products require a score of at least 75%. Some Great Value software will also score well enough to be a Best Buy. 

Check out our best antivirus software 2023 for Windows computers and our best antivirus software for Apple Macs. 

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