Roundup
Best Free Antivirus Software Compared
Free antivirus falls into three categories that search results constantly blur together: software that is permanently free, software that is free for a limited trial, and free on-demand scanners that do not protect you in real time.
This page compares the permanently free options for Windows and states plainly what each one withholds to push you toward a paid tier.
Comparison table
| Real-time protection | Yes — Defender, Bitdefender Free, Avast, AVG, Avira, Panda Free | No — Malwarebytes free is on-demand only |
|---|---|---|
| Firewall included | Windows Firewall (with Defender) | Not in the third-party free tiers |
| Ransomware layer | Controlled folder access in Defender | Paid feature in Bitdefender, Avast, AVG |
| Upsell prompts | None in Defender | Frequent in Avast, AVG, Avira |
| Cross-platform free apps | Windows only for Defender's built-in component | Avast and AVG offer free Android and Mac apps |
The honest ranking
Microsoft Defender wins on integration, silence and zero cost, and it needs no download. Bitdefender Antivirus Free Edition wins on engine pedigree with a minimal interface. Avast and AVG offer the most features in a free tier but talk to you constantly. Avira sits in between and adds a software updater. Malwarebytes free is not a competitor to any of these — it is the cleanup tool you run in addition.
What every free tier holds back
Firewalls, ransomware remediation, unlimited VPN traffic, password managers, identity monitoring, parental controls and priority support are the standard paywall. None of those are detection features, which is why free antivirus is a reasonable choice for many people rather than a compromise on core protection.
Verdict
Use Microsoft Defender if you want zero effort. Use Bitdefender Antivirus Free Edition if you want a third-party engine with minimal noise. Add Malwarebytes free to either one for on-demand cleaning.
Products in this comparison
Frequently asked questions
- Is free antivirus safe to use?
- Free antivirus from a reputable vendor, downloaded from that vendor's own site, is safe. The risk with free antivirus is almost always the download source, not the software.
- Is free antivirus enough for Windows 11?
- For a patched machine with a careful user, yes. Enable controlled folder access and keep backups regardless of which product you choose.