Best Antivirus Software and Apps

Many Windows users believe they don't need to pay for antivirus software, and many Mac and Android users think they don't need protection at all. Windows' much higher profile makes it the biggest target, but the truth is that OS X/macOS and Android are equally vulnerable to malware.

We believe it's worth paying for Windows antivirus software, because even the best free software leaves out protection features we consider essential. But you don't have to spend a lot — many antivirus products are sold online for much less than their list prices. Mac and Android users have other options: Some of our favorite Mac AV products cost nothing, and most Android security apps have free versions.

Latest Security Alerts and Threats

— Mamba ransomware, famous for shutting down San Francisco's MUNI public-transit system last fall, is back, according to Kaspersky Lab. Researchers have detected it attacking businesses in Brazil and Saudi Arabia. ADVICE: Back up all your drives regularly, and keep your antivirus software updated.

— Microsoft's Patch Tuesday updates for August included a fix for a previously unknown flaw that would have made another ransomware worm like WannaCry possible. ADVICE: Update your Windows system.

— A new variant on the Svpeng Android banking Trojan that logs your keystrokes along with its primary goal of stealing your money. The variant infects even "fully-updated devices with the latest Android version and all security updates installed" — unless the device's default language is Russian. The Trojan poses as an Adobe Flash Player app on third-party app stores. ADVICE: Stick to Google Play, and install an Android antivirus app.

How We Tested

Our evaluations were based on an antivirus product's interface, performance, protection and extra features. Was the product's interface intuitive and user-friendly, or did it make it hard to find important tools? How badly did malware scans slow down the computer's performance? How good was the program at detecting and removing malware? Does the program have any additional tools, and are they useful?

All of our Windows tests were performed on the same Asus X555LA laptop running 64-bit Windows 8.1 (later upgraded to Windows 10), with an Intel Core i3 processor, 6GB of RAM and a 500GB hard drive containing 36GB of files. To assess a program's impact on system speed, we used our custom OpenOffice benchmark test, which matches 20,000 names and addresses on a spreadsheet. The longer it took the laptop to finish the test, the heavier the performance impact. For smartphones, we used the Geek bench 3 bench marking app.

Our Mac evaluations were conducted on a late-2013 MacBook Pro running OS X El Capitan 10.11. The Mac had a 2.6-GHz Intel Core i7 CPU, 8GB of RAM and 23GB of data on a 512GB SSD. For Android, we used a Nexus 6P smartphone running Android 6.0.1 Marshmallow.

For malware-detection scores, we've turned to two independent testing labs, AV-TEST of Germany and AV-Comparatives of Austria. Each lab regularly subjects the major antivirus brands' flagship products to stress tests involving hundreds of previously unseen pieces of malware, with AV-TEST adding 20,000 instances of known malware. We use the latest results from both labs.

Windows Antivirus Software Types

Most antivirus makers have three or four tiers of Windows products, with each price bump adding extra features, such as parental controls or cloud backups. But because each company uses a single malware-detection engine for all its Windows antivirus software, the cheapest item — even a free one — in any product line usually finds malware just as thoroughly as the priciest.

Not all users will need premium suites, or even midrange products. If you don't have kids, or if you already have backup software, the basic product may be enough.

The least-expensive paid Windows antivirus products, which generally list from $40 to $60 per year depending on the number of PCs covered, have the essentials. Definition updates and scans are automatic; websites and email attachments are screened, and the products are mostly easy to use. Some basic AV programs toss in extra features, such as file shredders or system optimizers, that are normally found in pricier products.