Windows PC users need a strong antivirus program to ward off malware attacks, to keep their computers running efficiently, and to safeguard their online identities and personal information. Paid antivirus suites have many features to protect children online, manage security on mobile devices, and monitor a computer's firewall, software updates and other features. But some users just don't want to — or can't — pay a yearly subscription fee for those extra features.
If that describes you, you've come to the right place. We've evaluated the most widely used free antivirus programs based on their malware protection, system impact, ease of use and useful extra features.
So which free PC antivirus product is right for you? Of the six free antivirus programs we reviewed, Avast Free Antivirus came out on top. It offers very good malware protection, has a small system-performance impact and includes features that rival those of midpriced paid antivirus suites, such as a password manager and a hardened web browser.
If you'd rather not fuss with settings, then try Bitdefender Antivirus Free Edition, which has even better malware protection but doesn't let you adjust (or do) much other than ward off threats.
How We Tested
To evaluate installation, ease of use, interface and performance impact, we installed each AV program on the same Asus X555LA laptop, which ran Windows 10 and featured an Intel Core i3-4005U processor, 6GB of RAM and 36GB of data on a 500GB hard drive.
We conducted our own tests on how much each antivirus product affected our laptop's performance, using our custom OpenOffice benchmark. We timed how long it took to run a quick scan and a full scan while the laptop crunched numbers in the background.
We also assessed how easy each program was to use, the number of useful extra features it offered (including free add-on software) and how insistently each program nagged us to upgrade to paid software.
Our malware-detection data comes from two independent evaluation labs: AV-TEST in Germany and AV-Comparatives in Austria. Each lab regularly tests major antivirus products for their abilities to detect zero-day malware and other threats.
Avast bought its rival AVG last year, and the two companies' malware-detection engines have been merged, with remarkable improvements. Avast Free Antivirus already had a friendly interface, a nearly imperceptible system impact and useful extra features, including a password manager and a network scanner. Now that its antivirus protection is almost perfect, we recommend Avast Free Antivirus without reservation.
Bitdefender's malware-detection rate is second to none. The company's free antivirus product covers all the basics and has a very low system-performance impact. But Bitdefender Antivirus Free Edition's bare-bones interface can be hard to figure out and offers few options — you can't even schedule a scan. It's best for users who want a set-it-and-forget-it security solution.
AVG and Avast are now part of the same company, and their unified malware-detection engine comes close to those of industry leaders such as Kaspersky and Bitdefender while having a light system-performance impact. But AVG AntiVirus Free got the short end of the deal, with fewer useful extra features than Avast Free Antivirus and misleadingly named new scans. The good news is that AVG's wide range of customization options is still available; the bad news is that you still get nagged to upgrade to paid AVG software.
Avira's malware protection has declined a bit as Avast's and AVG's have improved, which makes Avira Free Antivirus' heavy system-performance hit less tolerable. Its austere but option-packed interface can be intimidating at first, but it offers a high degree of customization. Avira does have a wide range of free add-on features, including a VPN client and a password manager. But be sure to read the fine print, because many of the best functions are reserved for paying customers.
Panda's malware-detection scores are better on Windows 10 than on Windows 7, and the company has a high rate of false positives, or benign files mistakenly flagged as malware. Panda's customizable user interface is gone, and its system-performance impact has grown. Worse, the software still tries to hijack your web-browser settings and won't let you opt out of system-data collection.
Windows Defender's once-subpar malware-detection rate has gotten better, but that doesn't mean you should rely on it just yet. The software, which is part of Windows 8.1 and Windows 10, still came in last among the six products we reviewed, and its high rate of false positives confirmed that ranking. Windows Defender has an inexplicably high system impact during full scans, and does nothing to protect non-Microsoft browsers from online malware. It also has nearly no extra features. Even if you don't want to pay for antivirus protection, you can do better than Windows Defender.
Malwarebytes Anti-Malware Free is not antivirus software. It can't protect a PC from infection, but it does an excellent job of cleaning out malware that's already on your system. Plus, it doesn't interfere with any antivirus software that's already installed. We recommend Malwarebytes Anti-Malware Free as a complement to any antivirus program.