How we test antivirus

When you download antivirus – 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 antivirus is hit with more than 10,000 samples of malware. 

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 every three months to ensure standards haven’t slipped.

The best antivirus 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 is designed to block malicious software, so to properly weed out the best from the rest 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 antivirus that pesters you with confusing messages and warnings, or wrongly zaps a file that you actually want to use (known as a false positive).

And we don’t test just once and say ‘job done’. We rerun our full protection assessment every three months to ensure the packages are still doing an effective job with the very latest malware. 

Will antivirus help me avoid scams?

Most antivirus claims 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 or click on a dodgy link/open a dodgy attachment. This is so we can measure whether the antivirus 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.

Keep your phone as safe as your computer - see our pick of the best free and paid-for mobile antivirus.

Is the software easy to install and use?

It's all very well for antivirus to pick up every piece of malicious software and spam email that's out there, but it still needs to be easy to use and unobtrusive.

We buy and install each antivirus on a ‘fresh’ computer, and rate this process, including what is and isn’t included. For paid-for software, we also rate how easy it is to stop the software licence from automatically renewing (and charging you) after it expires. And we buy it, just like you do, so we can be sure we're recreating the same conditions any user will have.

When we install it, we rate the initial set-up process and first scan, looking to see if it's easy for a beginner to set up properly. Whether it's antivirus that you pay for or is free, we'll tell you if it's going to be a breeze to use on your computer.

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.

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Does it include all the features I need?

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

If the supposedly premium features aren’t worth the money, we’ll flag that to you. It may be that a free antivirus - which are increasingly comparable to paid antivirus - will meet your needs just as well.

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

Will antivirus 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.   

We will flag any antivirus that makes opening a web browser or saving files take an age. This is known as our use of resources assessment.

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Should I install it?

We consistently test a range of antivirus every year so we can reveal the best free and paid-for antivirus. Our expert tests reveal how each performs when we throw a myriad of threats at them, and whether they can resolve those threats. 

We combine the results of all these assessments when we calculate the total test score, so that you can find the antivirus that combines the best 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:

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

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 82% or above. Mac packages need to have a score of 80% or higher. 

Great Value antivirus

Our Great Value badge signposts products, appliances, gadgets and tech that are excellent deals. When it comes to antivirus, 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 antivirus 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 2024 for Windows computers and our best antivirus software for Apple Macs. 

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