Do I need antivirus software on Windows?

Windows 10 and Windows 11 already include Microsoft Defender, so you always have antivirus. The real question is whether a third-party product adds features you need, such as cross-platform coverage, a VPN or ransomware rollback.

What is the best free antivirus software?

Microsoft Defender is built into Windows and needs no download. Bitdefender Antivirus Free Edition is the strongest permanently free third-party engine. The free version of Malwarebytes is an on-demand cleaner to run alongside either.

Is a free trial the same as free antivirus?

No. A free trial is paid software with a timer. Free antivirus has no expiry. We label every product on this site as free, freemium, trial-based or paid so the difference is never ambiguous.

United States · Windows, Android, macOS, ChromeOS

Find the Right Antivirus Software

Compare trusted antivirus software, explore free and paid protection, and find legitimate download options for Windows, Android and more.

Compare Antivirus Find Antivirus for Windows

Featured Antivirus Products

Bitdefender

Developer Offer + 1 Extra Month

A high-detection engine with a genuinely usable free edition on Windows.

Bitdefender S.R.L. · freemium · Reviewed 2026-08-09

Download Bitdefender

Norton 360

Developer Offer + 1 Extra Month

The core Norton security suite sold in Standard, Deluxe and higher US tiers.

Gen Digital Inc. · paid · Reviewed 2026-08-09

Download Norton 360

Malwarebytes

Developer Offer + 1 Extra Month

The cleanup tool that became a full antivirus — with a free on-demand scanner.

Malwarebytes Inc. · freemium · Reviewed 2026-08-09

Download Malwarebytes

Microsoft Defender

Already installed, already running, already free on every supported Windows PC.

Microsoft Corporation · built-in · Reviewed 2026-08-09

Download Microsoft Defender

ESET

Developer Offer + 1 Extra Month

A lightweight, highly configurable engine favoured by technical users.

ESET, spol. s r.o. · paid · Reviewed 2026-08-09

Download ESET

Avast

Developer Offer + 1 Extra Month

One of the most-downloaded free antivirus products, now part of Gen Digital.

Gen Digital Inc. · freemium · Reviewed 2026-08-09

Download Avast

Best Free Antivirus

Microsoft Defender

It is free and built in. There is nothing to buy.

Free option

Download Microsoft Defender

Bitdefender Free

This is the free version.

Free option

Download Bitdefender Free

Avast

Developer Offer + 1 Extra Month

Yes — Avast Free Antivirus for Windows, Mac and Android with real-time protection.

Free option

Download Avast

AVG

Developer Offer + 1 Extra Month

Yes — AVG AntiVirus Free for Windows, Mac and Android.

Free option

Download AVG

Avira

Developer Offer + 1 Extra Month

Yes — Avira Free Security with real-time protection.

Free option

Download Avira

Malwarebytes

Developer Offer + 1 Extra Month

Yes — a free on-demand scanner and remover for Windows. Real-time protection is a paid feature after the introductory trial.

Free option

Download Malwarebytes

Panda Dome

Developer Offer + 1 Extra Month

Yes — Panda Dome Free provides basic real-time protection.

Free option

Download Panda Dome

Antivirus for Windows

Best Antivirus Software for Windows 11 & PC

Compare antivirus software for Windows: built-in Microsoft Defender, free third-party options and paid suites, with setup advice for Windows 11 and Windows 10.

Windows

Antivirus for Windows 11: Free and Paid Options

Antivirus for Windows 11 explained: what the OS protects by default, the best free antivirus for Windows 11, paid alternatives and the settings to enable today.

Windows 11

Antivirus for Windows 10 PCs

Antivirus guidance for Windows 10: Defender's capabilities, free third-party options, lightweight picks for older hardware and why patch status matters most.

Windows 10

Free Antivirus Software: What Is Genuinely Free

Free antivirus explained: which products are permanently free, which are trials, which are on-demand scanners only, and what every free tier holds back.

Free Antivirus

Free Antivirus Software for Windows

Free antivirus software for Windows compared: Microsoft Defender, Bitdefender Free, Avast, AVG and Avira, plus safe download advice and what each tier omits.

Free Windows Antivirus

Windows Virus Protection Explained

How virus protection works on Windows: Defender, SmartScreen, the firewall, controlled folder access and third-party layers, with the settings that matter.

Windows Virus Protection

Antivirus Free Trials: How They Actually Work

Antivirus free trials explained: how they differ from free software, auto-renewal traps, which vendors offer trials and how to cancel before you are charged.

Free Trials

Antivirus Comparisons

Best Antivirus Software Compared

Compare the best antivirus software for Windows and other platforms: protection, features, performance, privacy, pricing model and who each product suits.

Roundup

Best Free Antivirus Compared

Compare genuinely free antivirus software for Windows, including Microsoft Defender, Bitdefender Free, Avast, AVG and Avira, plus what each free tier leaves out.

Roundup

Antivirus for Windows Compared

Compare antivirus software for Windows 11 and Windows 10: built-in Defender, free third-party tiers and paid suites, with footprint, features and best-fit guidance.

Roundup

Norton vs Bitdefender

Norton 360 vs Bitdefender compared on protection approach, features, system impact, privacy, pricing model, free options and which user each one suits best.

Head to head

Norton vs McAfee

Norton 360 vs McAfee Total Protection compared on device coverage, identity monitoring, VPN, firewall, system impact and renewal pricing for US households.

Head to head

Bitdefender vs McAfee

Bitdefender vs McAfee on detection approach, free options, device coverage, identity protection, system impact and value for US Windows and mobile users.

Head to head

Latest Security Guides

What Is Antivirus Software?

Antivirus software explained in plain English: what it scans, how real-time protection works, what it cannot stop, and whether you still need it today.

6 min read

How Does Antivirus Software Work?

How antivirus software detects malware: signatures, heuristics, behavioural monitoring, cloud reputation and sandboxing, plus why false positives happen.

7 min read

Do You Need Antivirus Software on Windows?

A straight answer on whether Windows still needs antivirus software, what Microsoft Defender already covers, and when a third-party product is worth installing.

6 min read

Is Free Antivirus Safe?

Free antivirus can be perfectly safe — or a liability. Here is how to tell the difference, which free products are legitimate, and what free tiers hold back.

5 min read

Best Antivirus Features to Look For

A practical checklist of antivirus features worth paying for — and the ones that are marketing filler — so you can compare security software on substance.

6 min read

How to Scan Windows for Viruses

Step-by-step instructions for running a full virus scan on Windows 11 and Windows 10 with Windows Security, plus offline scans and second-opinion scanners.

6 min read

How to Remove Malware From a PC

A complete malware removal process for Windows: disconnect, scan offline, clean with a second-opinion scanner, reset browsers and verify the PC is actually clean.

8 min read

How to Remove a Virus From Windows

Remove a virus from Windows using built-in tools: safe mode, offline scanning, quarantine handling, startup cleanup and confirmation that the PC is clean.

7 min read

How to Remove a Trojan

Identify and remove trojan malware on Windows: symptoms to look for, offline scanning, credential cleanup and how to stop it coming back.

6 min read

Frequently Asked Questions

Do I need antivirus software on Windows?: Windows 10 and Windows 11 already include Microsoft Defender, so you always have antivirus. The real question is whether a third-party product adds features you need, such as cross-platform coverage, a VPN or ransomware rollback.
What is the best free antivirus software?: Microsoft Defender is built into Windows and needs no download. Bitdefender Antivirus Free Edition is the strongest permanently free third-party engine. The free version of Malwarebytes is an on-demand cleaner to run alongside either.
Is a free trial the same as free antivirus?: No. A free trial is paid software with a timer. Free antivirus has no expiry. We label every product on this site as free, freemium, trial-based or paid so the difference is never ambiguous.