Do I need antivirus on my computer?

What antivirus software actually does

Antivirus software looks for malicious programs and stops them from running or spreading. The term is older than most of the threats it now handles, and modern products deal with far more than viruses in the strict sense. They look for ransomware, which locks files and demands payment; spyware, which quietly collects information; trojans, which pretend to be something useful; and unwanted programs that change browser settings or show advertising.

Most products combine a few methods. They compare files against a list of known malicious software, which the vendor updates constantly. They watch how programs behave, so that something trying to encrypt hundreds of documents in a few seconds is stopped even if it has never been seen before. Many also check downloads and websites against reputation lists. None of these methods is perfect, which is why security agencies describe antivirus as one layer among several, not a complete answer.

The NCSC's consumer site, Own Your Online, frames everyday security around a small number of habits: keeping devices updated, using strong and unique passwords, turning on two-step verification and backing up important files. Antivirus supports those habits; it does not replace them.

What Windows already includes

Windows 10 and Windows 11 include an app called Windows Security. Inside it is Microsoft Defender Antivirus, which scans files in real time, receives frequent updates through Windows Update, and can run full or quick scans on request. The same app manages the Windows firewall, checks downloaded apps and files against Microsoft's reputation service, and offers ransomware protection for chosen folders through a setting called controlled folder access.

To see what is running on your computer, open the Start menu, type "Windows Security" and open the app. The home screen shows a series of tiles. A green tick on each means the protection is active and nothing needs your attention. If you have installed another antivirus product, the Virus and threat protection tile will usually name that product instead, because Defender steps aside when another real-time scanner is registered.

The most important point about Windows is that protection depends on support. Microsoft publishes the dates on which each version stops receiving security updates on its lifecycle pages. A computer running a version past that date continues to work, but newly discovered weaknesses in Windows itself are no longer fixed. Third-party antivirus can still catch known malware on such a machine, yet it cannot patch the operating system underneath, so the safer step is moving to a supported version.

What macOS already includes

Apple builds several protections into macOS. Gatekeeper checks that apps come from identified developers and have been reviewed by Apple before they are allowed to open. XProtect looks for known malware when apps are launched or files are changed, and Apple updates its definitions in the background. A further component removes known malware it finds. Apple describes the overall design in its Platform Security guide.

The common belief that Macs cannot get malware is not accurate. Malicious software for macOS exists, and some of it reaches people through fake app downloads or browser extensions. The built-in protections are designed to handle the most common of these. As with Windows, keeping macOS updated is the single most useful step, because Apple delivers security fixes through system updates.

What built-in protection tends to leave out

Built-in protection focuses on stopping malicious software. Third-party products, particularly the larger paid suites, often wrap extra tools around that core. Whether any of these matter to you is the real question behind "do I need antivirus?".

Management across several devices

Some subscriptions let one person see the status of every computer in the household from a single account. This can help if you look after a parent's or child's computer remotely.

Parental controls

Windows and macOS both have family settings of their own, but some households prefer a vendor's version that works the same way across different systems.

Password management

Browsers and operating systems now include password managers. Suites may offer their own, which some people find easier to share across devices and family members.

VPN

Some suites bundle a virtual private network. A VPN changes how your internet traffic reaches websites; it is not a form of malware protection.

Direct support

Paying a vendor usually includes some level of customer support, which can matter to people who would rather not troubleshoot on their own.

If none of these appeal, the built-in protection on a supported, updated computer is likely to be enough. If one or two of them would genuinely help your household, that is a reasonable basis for comparing paid options.

When households tend to add more

Some situations make a separate product more worth considering. None of them is a rule, and you should weigh them against cost and complexity.

• Several people share one computer, including children who download games, mods or browser extensions.
• You look after the computers of relatives who live elsewhere and want one place to check them.
• You prefer to have a company to contact when something seems wrong.
• You want specific tools, such as parental controls, that behave the same across Windows and Mac.
• You use a personal computer for work and your employer asks for a particular level of protection. In that case follow your employer's instructions first.

Habits that matter more than any product

Security agencies consistently point to a few habits that reduce risk more than a choice of software. They are free and take little time once set up.

1. Turn on automatic updates for the operating system, the web browser and any apps that offer them. Most attacks rely on weaknesses that already have a fix.
2. Use a different password for each important account, ideally stored in a password manager, and start with email, because email is how other accounts are reset.
3. Switch on two-step verification wherever it is offered, especially for email, banking and social media.
4. Back up files you could not replace, such as photos and documents, to an external drive or a cloud service, and keep at least one copy disconnected.
5. Download software only from the developer's own site or the official app store, never from a link in an unexpected email or pop-up.

Own Your Online has short, practical guides for each of these, and they are written for ordinary households rather than technical readers.

A simple way to decide

Work through these questions in order. Stop as soon as you reach an answer.

1. Is your operating system still supported and updating automatically? If not, sort that out first; it matters more than antivirus.
2. Is the built-in protection switched on and showing no warnings? If not, turn it on or follow the prompts in Windows Security or System Settings.
3. Is there a specific feature your household would use that built-in tools do not provide? If not, you probably do not need to buy anything.
4. If there is, compare products on independent test results, renewal costs and cancellation terms, using the method in How to choose antivirus for a home computer.

Questions people ask