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How to choose the best antivirus software

By Adam Marshall

Protecting your PC or Mac from a virus is easy with internet security software. We have expert advice on picking out the best antivirus, and whether free antivirus is worth considering.

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The internet is full of threats, but that's no reason not to enjoy the best of the web - the key is keeping your Mac or PC properly protected with an internet security package.

Viruses and malware can infect your computer in several ways, but the best antivirus software will give you peace of mind that your computer and personal data are safe.

Take a look at our antivirus software Best Buys to discover the products that Which? recommends.

Choosing the best antivirus for you

Shall I go for paid-for or free software? Do I need any extra features? Is my integrated Windows or Mac security enough? If you've ever asked any of these questions before downloading internet security, our interactive choosing tool will help you unwind the confusing web of options.


Paid-for antivirus software

Many people keep their computer safe by paying for a security suite (almost half of Which? members, according to our recent survey), which will usually include antivirus software, protection against scams and a firewall. Depending on how many devices you want to protect, your security package is likely to cost between £20 and £70 for one year.

Paid-for security software suites often come with extra features such as parental controls and tools for maintenance, back-up and recovery that can help you restore your computer in the event of a disaster. Generally, they also have better customer service and technical support than free internet security. So if there's a particular feature or function you want, make sure the program you download has it.

Most brands have options for just one device or, for more money, multi-user licences so you can install the same protection on two or more computers in your home. Some also allow you to pay extra up-front for a further year or two of cover.

Pros: Provides an all-round security solution accessed through a single interface. Individual components are automatically updated at the same time so you get protection against the latest threats.

Cons: They can be expensive and you’ll also face ongoing costs, usually in the form of an annual subscription, to receive updates after the initial period of protection is over (usually a year). Some security suites can place a drain on system resources, too, potentially slowing down your computer.

Check out our pick of the best antivirus software.

Free antivirus software

You may not need to buy security software. Depending on the type of computer you have, it may already come with certain security features installed on it. For example, Windows 8.1 and Windows 10 PCs come equipped with Defender – see more below.

Alternatively, you can download free antivirus tools from the internet that provide a good level of protection. And it’s possible to get most of the features that are included in paid-for internet security by using a combination of free antivirus downloads, although they won’t be packaged up neatly in one place, and you can risk compatibility problems.

Pros: You can use your chosen antivirus, anti-spyware, anti-spam and firewall programs in tandem to completely protect your PC or Mac without spending a penny. And, because they’re free, you can try out different packages before settling on the one for you.

Cons: They provide only a basic level of protection and lack the extra features of paid-for security software. You’ll have to keep each individual program updated to ensure you’re protected against the latest threats. Plus, free antivirus software is typically for use on a single computer, so you’ll need to download, install and manage a separate version if you have more than one computer.

Download a package to give you peace of mind with our best free antivirus software.

Windows 8 security and Windows 10 security

The biggest shake-up in PC security for years came with Microsoft’s launch of Windows 8. Unlike previous versions, it came with lots of security features integrated into the operating system.

One of the key changes was the replacement of Microsoft Security Essentials with Windows Defender. Defender has been beefed up to include antivirus protection along with anti-spyware features. It runs in the background and notifies you when you need to take action.

Windows 8 and 10 users are further protected by a two-way firewall that monitors the information going back and forth to the internet. Other features include a SmartScreen filter to help protect against phishing scams, plus parental controls to monitor children’s activities online. Windows 8 and Windows 10 both include a Secure Boot option that prevents malware from gaining a foothold on your PC during start-up.

Pros: We found that Microsoft Windows 8 and 10 have strong built-in security and antivirus features. 

Cons: Because of the sheer amount of Windows users, Microsoft’s operating system is frequently made the target of hackers and virus creators. If Windows Defender is your only line of defence, we’d still recommend upgrading to a standalone security program. And PC users with versions of Windows prior to Windows 8 should certainly install separate security software – nowadays, Microsoft Security Essentials just isn't watertight enough.

Click to read our full Windows 10 Defender review.

Mac security software

Despite their reputation for being more secure than Windows PCs, Apple Mac computers are not immune from viruses and malware. With more Apple products being sold, the target audience for hackers is becoming more attractive. This makes it more likely that viruses will be designed specifically to attack Macs, so it makes sense to think about Mac security software.

In fact, we've seen a recent increase in Mac malware, typically in the form of annoying pop-up adverts and software that makes unwanted changes to settings, or causes other programs to malfunction.

Apple continues to boost security in each new version of the MacOS operating system. But Macs do not include antivirus or anti-spyware software, although they do have a built-in firewall to block attacks from malicious users online. There’s plenty of paid-for and free security software for the Mac to choose from.

Pros: Apple computers are generally less vulnerable than PCs, so you may decide that you don’t need to splash out on antivirus software for your Mac.

Cons: Perhaps due to Apple computers' reputation for being less susceptible to malware, there aren’t a huge amount of security packages available – and those we have tested scored worse, on average, than antivirus suites for Windows.

Get the best package for your Apple Mac - we’ve picked out the best antivirus software for Apple. 

Do I need two antivirus programs?

There's a long-standing adage that using two antivirus products is a bad idea because they can cause glitches, with two programs trying to perform the same task. Limiting yourself to one internet security program also minimises the negative impact of antivirus software on the performance of your PC.

It’s not always a security power struggle, however. Some additional programs can prove invaluable if you’re after a second line of defence.

Pros: We've seen some security software that usefully bolsters the malware-fighting elements of your main antivirus package. Malwarebytes Anti-Malware, for example, is a standalone security tool that can be installed alongside your regular security software - and it has a brilliant track record for vanquishing nasties. Plus, it's free.

Cons: It's true that having two full programs installed at the same time can seriously slow down your system. From time to time, they may both assume that the other package is scanning your system, leaving you vulnerable to malware that slips through the cracks. And if one Best Buy program is enough, why bother paying for two?

Removing old security software

Many antivirus packages will automatically attempt to remove rival products. This process typically happens as part of the installation of a new security suite, although this isn't always the case.

If you need to manually remove an older package on Windows, click Control Panel (or search for this within the Start menu) then, under Programs, click Uninstall a program and locate the software you want to remove from the list. Select the program, and then hit Uninstall in the toolbar above.

But beware: if you uninstall your PC’s defences to install another, but don't install another one immediately, you will be left unprotected.


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