Best Free Antivirus for Windows 11 in 2026: 7 Free Options Ranked

Last verified 4 October 2026. The best free antivirus for Windows 11 is the one already on your PC: Microsoft Defender Antivirus scored 17.5 out of 18 in AV-TEST's August 2026 Windows 11 test and 99.0% in AV-Comparatives' February to May 2026 Real-World Protection Test, with no ads. Is Windows Defender enough? For most people, yes. The best third-party free option, Avast Free Antivirus, adds a Wi-Fi inspector and its own firewall, but it also brings upgrade prompts and bundled trials. Below are 7 free options we checked against each vendor's own site this week, compared on what the free tier includes, what it lacks, and what the paid step-up costs.

Toolradar data: of the 716 tools in our security category, 94 are completely free and another 254 are freemium.

Quick Comparison

Our picks: the best free antivirus for Windows 11, ranked

1. Microsoft Defender Antivirus

Microsoft Defender Antivirus is part of the Windows Security app, which Microsoft says is built into Windows so your device is protected from the moment you start it up. It includes real-time protection and Windows Firewall. Its ransomware protection, Controlled folder access, stops unknown apps from changing files in protected folders once you turn it on.

The labs rate it near the top. AV-TEST's August 2026 Windows 11 test of 15 products gave Microsoft Defender Antivirus 6 for protection, 5.5 for performance and 6 for usability. In AV-Comparatives' Real-World Protection Test (400 test cases on Windows 11), Microsoft blocked 396 and scored 99.0%, earning the top ADVANCED+ award. Bitdefender scored 99.5%, while Avast, AVG and Norton scored 99.3%.

What it lacks is the extras: no bundled VPN or password manager. Microsoft 365 Family and Personal subscribers also get the separate Microsoft Defender app on Windows, Mac, iOS and Android. Install another compatible antivirus and Defender switches itself off.

Pick it if you want solid protection with no ads, no account and nothing to configure beyond turning on ransomware protection.

2. Avast Free Antivirus

Avast Free Antivirus has the richest free tier here. Avast lists File Shield, Behavior Shield, Web Guard (for scam sites and phishing links), Mail Shield for email attachments, a network inspector for Wi-Fi, a firewall and Ransomware Shield. Avast added the firewall to the free edition in January 2022 and Ransomware Shield in August 2020, according to its newsroom.

Labs back it up. AV-TEST's August 2026 test lists Avast Free Antivirus 26.6 at 6, 6 and 6, and AV-Comparatives tested Avast One Free Antivirus at 99.3% with an ADVANCED+ award.

Premium Security adds what Avast's support FAQ calls premium features: Remote Access Shield, Sandbox and Webcam Shield. It costs $49.08 for the first year on one PC and renews at $77.99; a 10-device plan is $69.48 and renews at $99.99.

The catch is the upselling and the history. The free download page pushes a 60-day SecureLine VPN trial that needs a payment method and bills at the end unless cancelled. In June 2024 the FTC finalized an order banning Avast from selling or licensing web browsing data for advertising and requiring it to pay $16.5 million.

Pick it if you want a third-party free tier with its own firewall and Wi-Fi inspector and can decline the extras.

3. AVG AntiVirus Free

AVG AntiVirus Free offers real-time protection, AI-based scam and unsafe-link blocking, a home Wi-Fi check, ransomware protection and an alert if your email password leaks. It is for personal and family use only. AVG lists Windows 11 support, including ARM chips, and needs 4 GB of RAM.

It tests like Avast because it runs the same engine, which AV-Comparatives notes for AVG, Avast and Norton. AV-TEST's August 2026 test lists AVG Antivirus Free 26.6 and 26.7 at 6, 6 and 6, and AV-Comparatives scored AVG AntiVirus Free at 99.3% with an ADVANCED+ award.

The free tier has no firewall; AVG sells that in Internet Security. For one Windows PC it costs $39.99 for the first year only (list $77.99, shown as 49% off) and adds an enhanced firewall, webcam protection and fake-website protection.

Pick it if you want Avast's engine under a different brand and do not need a free firewall.

4. Bitdefender Antivirus Free

Bitdefender Antivirus Free is the quietest free option. It needs a Bitdefender Central account and no credit card, runs on Windows only, and works on Windows 10 and 11. Bitdefender says it detects suspicious changes in real time, includes Advanced Threat Defense and basic ransomware protection, and avoids pop-ups.

Its comparison table also says what you give up against paid Antivirus Plus: anti-tracking, social network protection, full-system analysis for outdated software and unsafe settings, and the productivity and entertainment mode. No firewall is listed. Antivirus Plus costs $24.99 for the first year for one device or $29.99 for 3, with the first-year price flagged on the page.

One caution on the labs. AV-TEST and AV-Comparatives tested Bitdefender Total Security, not the free app: 6, 6 and 6 at AV-TEST and 99.5% (ADVANCED+) at AV-Comparatives. Treat those as a guide to the engine, not a score for the free edition.

Pick it if you want a third-party scanner that stays out of the way and does not mind a Windows-only app with the basics.

5. Avira Free Security

Avira Free Security is a free bundle: antivirus, a VPN, a basic password manager, a browser extension with phishing protection, tune-up tools and a software updater on Windows. Avira says Free Antivirus and Free Security are now the same product, and it lists Windows 11 as supported.

The limits are clear. The VPN is capped at 500 MB a month (see our best free VPNs for better), and password management is basic. Avira Prime adds the Avira Firewall, web and email protection, unlimited VPN and advanced ransomware protection. Prime is priced by region, so check the current price on Avira's site.

AV-TEST's August 2026 test lists Avira Internet Security for Windows 1.1 at 6, 6 and 6, a paid edition, so there is no lab score for the free app.

Pick it if you want a free VPN and password manager in the same installer and rarely need more than 500 MB of VPN a month.

6. Malwarebytes Free

Malwarebytes Free scans and removes malware on demand; real-time protection is reserved for Premium, which Malwarebytes sells as "advanced 24/7 real-time protection." That makes it a second opinion, not a replacement for Defender.

The labs tested Premium. AV-TEST lists Malwarebytes Premium 5.5 and 5.6 at 6, 6 and 6, while AV-Comparatives scored it 98.8% with a STANDARD award, which it notes was lowered because of false alarms.

Premium Standard lists at $59.99 a year for 3 devices. Malwarebytes was discounting it to $35.99 through October 11, so check the price at checkout.

Pick it if you want a manual scanner for cleaning up a PC you suspect is infected.

7. Panda Free Antivirus

Panda Free Antivirus covers 1 device. Panda's comparison table shows the free tier as antivirus plus a free VPN limited to 150 MB a day, with the firewall, secure shopping and browsing, Wi-Fi protection and parental control reserved for paid Panda Dome plans. Those plans are priced in euros per month on the page, starting at 4.45 EUR.

It ranks last on evidence. AV-Comparatives tested Panda Dome Advanced, a paid edition, at 96.5% (386 of 400 blocked) with the lowest TESTED award, lowered by false alarms.

Pick it if you are comparing every free option and want a fallback with a small free VPN.

How to choose a free antivirus for Windows 11

Start with what Windows already gives you. Windows Security includes Microsoft Defender Antivirus, Windows Firewall and Smart App Control. If you install a compatible non-Microsoft antivirus, Defender turns itself off, so you are swapping engines, not adding a layer. To see who is protecting you, open Windows Security, choose Virus & threat protection, then Manage providers.

Decide what you want to add. The free tiers add a Wi-Fi inspector (Avast, AVG), a capped free VPN (Avira, Panda) or a basic password manager (Avira). If you want none of those, stay on Defender.

Read the lab names closely. AV-TEST and AV-Comparatives tested the free editions of Avast and AVG but paid editions of Bitdefender, Malwarebytes, Avira and Panda. The top scores sit within a point or two of each other (99.0% to 99.5%), so ads, upsells and privacy matter more than a fraction of a percent.

Count the upsells. Avast pushes a payment-method trial, AVG is for personal use only, and every free tier here points to a paid plan. Compare renewal prices, not first-year ones: Avast Premium goes from $49.08 to $77.99 and AVG Internet Security lists $77.99 against $39.99.

Skip Kaspersky Free if you are in the US. On June 20, 2024 the Commerce Department's Bureau of Industry and Security announced a final determination prohibiting Kaspersky from providing its software in the United States. Under the BIS prohibition, Kaspersky could not sign new US agreements from July 20, 2024 or provide antivirus signature updates after September 29, 2024, so we do not rank its free product.

Know the paid alternative. Norton's antivirus is a paid product. Norton 360 AntiVirus Plus covers one device for $29.99 for the first year and renews at $59.99; AV-TEST's August 2026 test lists Norton 360 at 6, 6 and 6. Our best antivirus software guide compares paid suites.

FAQ

Is Windows Defender enough?

For most people, yes. It has real-time protection and a firewall, scored 6, 5.5 and 6 at AV-TEST in August 2026 and 99.0% at AV-Comparatives, and costs nothing. It lacks a bundled VPN and password manager, and its ransomware protection is something you turn on.

What is the best free antivirus for Windows 11?

Microsoft Defender Antivirus, because the labs rate it close to Avast and AVG and it has no ads. If you want a third-party app, Avast Free Antivirus has the most features in its free tier, including a firewall and Ransomware Shield.

Can I run Defender and another antivirus together?

Not as two real-time scanners. Microsoft says Defender turns itself off when you install a compatible non-Microsoft antivirus, and Microsoft Learn says passive mode is only for devices onboarded to Defender for Endpoint, a business product. Malwarebytes Free is different because it scans only when you run it.

Is free antivirus safe to use?

The protection engines are credible, but the business model matters. Avast settled an FTC case in 2024 after the agency said it sold browsing data collected through its software. Read the privacy settings, skip the browser extensions you do not need, and decline bundled trials.

Which free antivirus has a firewall?

Avast Free Antivirus includes one. Windows also has Windows Firewall built in. AVG and Avira sell their firewalls in the paid Internet Security and Prime plans.

Is Kaspersky Free available in the US?

No. The Commerce Department barred Kaspersky from new US agreements from July 20, 2024 and from providing antivirus updates after September 29, 2024.

Bottom line

Stay on Microsoft Defender unless you want something it lacks: for most Windows 11 users it is enough. If you want a third-party free tier, install Avast Free Antivirus and decline the trials, or pick AVG AntiVirus Free for a smaller bundle. Keep Malwarebytes Free for occasional second-opinion scans, and pay only if you need a firewall or webcam guard Defender does not give you.