Fortunately, a really great free antivirus app doesn’t also have to hit you with performance issues you might expect from tools like these, like bloated RAM usage, excess bandwidth, etc. We’ve selected these particular apps because they excel with respect to usability, system resource requirements, user reviews, and feature set. Here are the four best antivirus apps for Android, each with their own unique advantages: It can scan each time you disconnect from a computer as well as start scheduled scans once a day, every day. If that isn’t enough for you, you can always start a manual scan whenever you want to check for malware like adware, riskware, ransomware, and potentially unwanted programs. When threats are found, you’ll be alerted of the threat type (riskware, PUP, etc.) and will have the option to ignore them or delete them on the spot. Here are some other things Avira’s app is capable of: updated apps are re-scanned when they’re finished updating to ensure that any new files aren’t infected; you define whether files and/or apps are scanned; show notifications when threats are found—handy so that you aren’t bombarded with messages each time it finds the device clean; an anti-theft tool lets you find your device remotely or lock or wipe it; apps with privileged access to your information are categorized by risk level; an Activity section shows a history of what Avira has been doing and what it finds; Overcharging Protection can remind you to unplug the device when it’s fully charged; and the Identity Safeguard function checks company breaches to see if your email was included in any of them. This free version is very much like the professional edition you can buy except that the paid version doesn’t contain ads, will update its definitions every hour, includes an app locker, and supports the secure browsing feature that helps your device stay clean when browsing the web, downloading files, and shopping online. The only manual thing you can do with Bitdefender is to start with a scan and choose whether to include an SD card in the check against viruses and other threats.  Once the full scan has completed, you’ll be protected against any new app installs and updates automatically so that they’re blocked before they can do any damage. If a threat is found, you’ll be taken into the results screen, where you can easily uninstall the culprits. Bitdefender is said to be super light on resources since it doesn’t download and store virus signatures on the device, but instead uses cloud-based protection to check for the latest safeguards against outbreaks. The only drawback to Bitdefender Antivirus is when you compare it to their not-free Mobile Security & Antivirus app, which checks your browsing habits in real-time and can lock down or wipe your phone if it’s stolen, which are pretty handy features. It supports scheduled scans, protects against malicious apps, can scan the files stored on the internal storage device, warns you about apps that other AVG users have reported as a threat, and can treat potentially unwanted programs as malware. Also, this app protects you while browsing the internet in Chrome, too. Much like some of the other Android AV apps in this list, this one doesn’t include just a virus scanner: if you have root access you can also enable the AVG firewall; an internal photo vault can hide select images within the app, protected behind a custom passcode; it can clean some junk files and caches that you don’t need anymore to free up disk space; an internet speed test is built-in; security threats can be found by scanning the network you’re connected to; improve the performance of your device by shutting down things that are running in memory; get a warning when you reach 10% or 30% battery life; find the permissions all your apps have; view and monitor data usage to avoid overage charges; virus definitions can be configured to only download when you’re connected over Wi-Fi; free users can remotely lock their device through a web browser that communicates with the app—also supported are SMS commands that are used to trigger a call from your device, a data wipe, a siren or lock request, and more. The biggest downfall with this Android antivirus tool is that it’s littered with advertisements; they’re on almost every single screen. Plus, you’re always just one tap away from upgrading to the pro version from every area of the app, which is frustrating if you accidentally tap it. It’s also annoying when AVG finds risks that aren’t actually malicious. However, if you do like to have those kinds of alerts, even if no files or apps are found to be harmful, then you won’t have a problem with that. For example, after a scan, you might be told that the “unknown sources” option is disabled on your phone that would normally tell you when you’ve installed an unofficial app that could contain threats. While that feature should probably always be enabled, disabling it doesn’t necessarily mean you are currently under attack or have infected files. App backup, camera trap, device lock, VPN protection, app lock, and no ads, are a few of the unsupported features in the free edition. There are also various links to features that you can only get in other apps, so you might find yourself leaving AVG for the Play Store when you try tapping those options. The only scan setting you can turn on is the one for deep scanning so that it checks more of your device than the typical scan, though it also takes longer to scan everything. On our test device, the regular scan checked hundreds of apps and over 150 files in under 10 minutes. A related security tool in this app is the security audit that shows unsecured system settings that might be on, like developer mode. The privacy checker shows which apps can do things like see your location, read your messages, access your files, etc. A lot of what you see in the app is not free. Premium features include real-time protection (only on-demand scans are supported for free), ransomware and spyware detection, and alerts for when you visit malicious sites. There’s a free 30-day trial of premium if you want to try it out.