Many antivirus services claim to offer free online scanning tools, but very few are actually cloud-based services. Most require you to download software in order to work.
While an online virus scanner can not replace your antivirus which runs offline continually in the background, it can be helpful for quickly identifying infections.
What is a Virus Scanner?
A virus scanner is a web service that scans your device from a remote server. As it’s not as powerful as a full-scale antivirus — and some of them work from the cloud — there is little to no system lag.
If you suspect that your device is infected with a virus and you haven’t yet installed a paid antivirus, then a free online virus scanner can provide a quick and easy solution without having to download and install any software.
However, not all virus scanners are the same, and very few are actually free, web-based services. They also vary considerably in terms of accuracy, customization, and added features.
How We Tested Them
To evaluate which are truly the best online virus scanners, we used a device with several known malware infections and tested it using the most popular and robust online virus scanners we could find.
Then we rated them according to the following criteria:
- Ease of Use
- Online vs. Download
- Ability to Identify Infections
- Additional Features
We compared many virus scanners, including Kaspersky, Trend Micro, and MetaDefender Cloud, and found that, though these are good free online scanners, the ones on this list provided better all-around protection.
The following seven ranked highest on all factors:
- SafetyDetectives Vulnerabilities Scanner
- ESET Online Scanner
- F-Secure Online Scanner
- Norton Security Scan
- BullGuard Online Virus Scan
- Bitdefender Home Scanner
Let’s look at each online virus scanner in more detail…
1. SafetyDetectives Vulnerabilities Scanner (No-Download Required)
Unlike many of the other online virus scanners we tested, the SafetyDetectives Vulnerabilities Scanner doesn’t require a download. It runs a thorough scan to pick up any threats, and then explains how to fix them.
The scan takes only a few seconds and provides a high level of accuracy when identifying system vulnerabilities across all platforms. Again, it doesn’t repair the problem, but it tells you how to fix it. So while it’s free, light, and very quick, it should only be relied on for identifying problems, not mending them.
- No download required.
- Scans entire system within seconds.
- 100% accuracy rate.
- Free service.
- Clearly explains how to rectify the problem.
- Indicates level of threat.
- No ads.
- Does not repair recognized vulnerabilities.
- No options for customization.
While many antivirus companies claim to offer a web-based scanner, the fact is few actually do. SafetyDetectives’s Vulnerabilities Scanner is one of a couple exceptions.
While not technically considered a full-scale antivirus, this online scanner offers a quick and easy to use cloud-based solution. If it detects an issue, it provides a threat-level warning and gives suggestions/advice on how to rectify the problem.
As a truly free, cross-platform solution, it’s a great online tool for quick check-ups without the need for a download or subscription.
2. VirusTotal (No-Download Required)
VirusTotal is a free online scanner that analyzes suspicious files and URLs for suspected malware by referencing a large online database of known infections.
Though it scans uploaded files impressively fast, it’s only able to analyze one at a time. It’s pretty annoying to run every single file on your PC through a full system scan. While it operates as a true web-based scanner — as it cannot remove any threats — it simply can’t be classified as a system-wide detection tool.
- No download required.
- Free service.
- High level of accuracy.
- Performs quickly.
- Several scanning options.
- Comprehensive reporting.
- Limited to one file/URL at a time.
- Unable to remove infection.
I was impressed with how quickly VirusTotal worked and how detailed the analysis report was. It ran one .doc file through 58 different antivirus engines, which was impressive.
After performing the online scan for malware, it automatically shared the results with its community of users, thereby checking in with a real-time database of global security threats. As a free and truly online tool, it’s great for one-off checks but not robust enough to perform a system-wide scan.
Test the VirusTotal Scanner >>>
3. ESET Online Scanner (Download Required)
The ESET Online Scanner is a reduced version of the full ESET Security Suite. This download-only scanner provided flawless accuracy when identifying infections and was able to name and locate every suspicious file on our testing device.
Although the scan took 30 minutes — which is longer than other scanners — it thoroughly explored the operating memory, auto-start locations, and local drives.
ESET lets you delete or quarantine an infection, which is not an option with some virus scanners.
The major drawback? It’s only available on 32-bit and 64-bit Windows systems; so if you use a different operating system, you’ll have to look elsewhere.
- Scans your entire computer.
- 100% accuracy rate.
- Includes anti-stealth technology (anti-rootkit).
- Scan customization available.
- Comprehensive report available.
- Downloadable add-on required.
- Only available on Windows.
- Full scan takes 30 minutes.
The ESET Online Scanner offers a more in-depth virus scan than many of its competitors. Although it takes longer to scan, the level of detail of the scan and the results are worth the wait. Even if it didn’t have the option to delete/quarantine (which it does), it still would be easy to locate and delete the infected files manually.
I was disappointed that a download was required for this virus scanner, but ESET is a high-quality service, and it is definitely worth it. The amount of customization is also notable. You can specify which features you want to use, and you can set up automatic scans.
The scanner is available for one-off use, but you can opt into a 30-day free trial of ESET’s full Security Suite. This package offers continuous, real-time protection before having to commit to a subscription or payment.
Test the ESET Online Scanner >>>
For complete protection, see ESET Deals >>>
4. F-Secure Online Scanner (Download Required)
F-Secure’s download-required virus scanner is sleek, simple to use and effective.
When tested, it removed the majority of malware on our device. The whole process was impressively fast for a download service, taking less than a minute. You can see information about any infected files with links to get more details online. The tool can also successfully remove malware via a system restart.
While very user-friendly, it’s currently only available for Windows, however the company offers a free trial of their F-Secure Safe software for Mac users.
- Removes infected files.
- 70% accuracy rate.
- Scans in less than a minute.
- Simple user interface.
- Regularly updated for new threats.
- Only available on Windows.
- No cloud-based scanner.
- No custom scan options.
- System-restart required.
The F-Secure virus scanner is definitely one of the best online virus scanners out there. While it requires a downloadable add-on, it takes up minimal memory.
The speed of the scan was another major selling point, as was the ability to actually remove threats. Although restarting the device was a slight inconvenience, a surprising number of other scanners don’t offer removal options at all.
Overall, the F-Secure Online Scanner is impressive as a well-rounded live threat detection tool. It didn’t manage to detect every single threat, but it still performed well in all areas.
Test the F-Secure Online Scanner >>>
For complete protection, see F-Secure Deals >>>
5. Norton Security Scan (Download Required)
Norton’s free Security Scan tool provides a quick and more detailed scan than many of its other competitors.
But like most online virus scanners, the Norton Security Scan requires a software download to work. So, it can’t be classified as a real, web-based scanning service.
However, when tested, it identified 70% of malware, alongside many suspicious cookies or outdated apps. While its results were broader than most, you still aren’t able to actually remove the infections. Instead, you’re redirected to purchase Norton’s full antivirus software.
The tool also doesn’t disclose the names and locations of the infections, so you can’t remove them manually. However, if you just want to check whether your system is infected with malware and then use another program to remove it, then Norton’s Security Scan is a decent option.
- Full system-scan.
- Suspicious cookies scan.
- Identifies system vulnerability.
- High rate of detection.
- Trusted and established brand.
- Not a true web-based service.
- Can’t erase infections.
- Only available on Windows.
- Tries to upsell you to full software.
Many online virus scanners try to upsell you to a paid antivirus, so the fact that Norton couldn’t disinfect my system didn’t come as much of a surprise. However, removing the infection is arguably the most important part of antivirus protection.
Despite this, the actual detection rate is pretty impressive. Instead of just highlighting malware, it thoroughly scans your device to uncover any potential security threats. If you already have an antivirus, Norton Security Scan is ideal for performing instant checks, instead of having to wait for a full system scan. Then, if you find an infection, you can switch to your installed software.
Unfortunately, Norton’s Security Scan isn’t compatible with Mac, but Apple users have the option to test out a trial version of any other Norton antivirus app without having to provide credit card information.Test the Norton Security Scan Tool >>>
For complete protection, see Norton Deals >>>
6. BullGuard Online Virus Scan (Download Required)
Cybersecurity giant BullGuard used to offer a dedicated online virus checker, however, they recently updated their system so users can now download a free two-month trial of their premium security packages. These free apps provide fewer features, so they take up less space on your computer.
They can also be accessed via any browser, offering higher compatibility than other similar tools. Unfortunately, it does take a long time to set up. Plus, it doesn’t have an instant scan setting; you have to select critical areas in a custom scan.
- Available on most browsers.
- Several options available.
- Premium quality.
- Available for 60 days.
- No dedicated online scanner.
- Long installation process.
It was surprising that BullGuard removed the online scanning tool from their site. However, their free trial options are still remarkably quick and convenient to use. That said, I wasn’t impressed by the significant amount of time it took to install. Not only did I have to go through a lengthy set-up process, I also had to create an account.
Although the client is well-designed, it doesn’t offer an auto-quick scan. To only search the critical regions, I had to create a custom scan and choose them manually.
Nevertheless, the results were promising. It found most of the malware. I didn’t expect anything less, as the app is just a smaller version of their premium antivirus engines.
While I wouldn’t recommend the BullGuard Virus Scan as my first choice, it did successfully achieve its goals eventually.
Test the BullGuard Online Virus Scan Tool >>>
For complete protection, see BullGuard Deals >>>
7. Bitdefender Home Scanner (Download Required)
Bitdefender’s Home Scanner is a download-only, low-usage app that’s part of Bitdefender’s free toolbox. You can use it to perform a quick scan of your device’s critical areas, do a full system check, or target a custom location. We chose the first option, and it completed the scan in less than one minute.
It picked up on some infections, but it didn’t find all the threats. I was able to quarantine the files, but I had to change my user privileges to be able to disinfect them. Overall, the scanner was generally effective but unnecessarily complex in some areas.
- Available on Explorer, Firefox, and Chrome.
- Takes less than a minute to scan.
- Adware removal tool also available.
- Identifies malware fast.
- Fastest option available.
- No detailed results.
- Download only.
- Some reports of interference with other apps.
- Limited accuracy.
The Bitdefender Home Scanner was by far the most complex. I liked how it listed each found threat, the “action taken,” and a route to manually locate the file. However, after locating the infections, it wasn’t clear how to delete them. Plus, the interface itself isn’t very attractive.
Once I finally managed to find my way into the settings, it was easier to see how everything worked. The scanner can be set-up to automatically disinfect or quarantine a file, if it’s possible. It wasn’t able to detect all of the known malware on the computer, which was clearly an issue, but it was capable of removing common threats.
I also tried out the adware removal tool but was disappointed that it only worked for two adware types. In summary, the Bitdefender Home Scanner can get the job done, but only with some effort and maybe a little inaccuracy.
Test the Bitdefender Home Scanner >>>
For complete protection, see Bitdefender Deals >>>
Paid Antivirus vs. Free Online Scanner
An online virus scanner can be used to identify threats quickly without committing to a paid service. However, as we discovered, very few cloud-based scanners actually exist, apart from the SafetyDetectives Vulnerabilities Scanner. In any case, an online scanner can never replace a full security suite.
At best, online scanners provide vulnerability detection, a basic overview of the problem, and guidance on solving the underlying issue. But they do not provide the ability to actually resolve the problem.
If you want to ensure that your device and files are safe, we recommend installing a highly-rated, premium antivirus.
Still not ready to purchase an antivirus? Then you may want to read about the best (and really free) Windows antivirus programs for 2021.