Windows Defender vs Avast: Step by Step Comparison


If you’re here, you may be wondering what is simply the best antivirus software available to protect your devices from malware. While many antivirus products exist, Windows Defender Antivirus was built into Windows 8, and significantly upgraded in Windows 10. How does Microsoft’s free antivirus stack up against the competition out there? That’s what we’re going to explore in this article, as we compare Windows Defender Antivirus against Avast.

We’ll be comparing Avast’s individual security suites against Windows Defender Antivirus, as well as the ease of use, reliability, and overall performance impact on your machine from each product.

Windows Defender vs Avast: Quick Comparison
Basic Protection: Avast Free Antivirus has better detection than Windows Defender, and offers additional free tools.

Advanced Protection: Avast’s higher subscription tiers offer useful tools, while Windows Defender does not offer any additional tools.

Performance Impact: Avast, by a tiny margin.

Overall winner: Avast has a lower impact on system performance.

Windows Defender Antivirus

Windows Defender logo

It can be said that Windows Defender Antivirus does not offer as many bells and whistles as other antivirus products available. However, it does cover all of the essential features you would expect, and it does them quite well.

Windows Defender Antivirus offers various scan types – quick scan, full scan, and custom scan. It also has an offline scan, which is a deeper malware scanning which will run before Windows completely boots up.

Some of the useful tools in Windows Defender Antivirus include the SmartScreen utility, which will block potentially hazardous websites, scans your downloads for malware, and it will also check for unrecognized apps across the web. However, the drawback of this tool is that it is only available for Microsoft Edge browser – so you lose out on this protection if you’re using Chrome, Firefox, Opera, or any other browser besides Microsoft Edge.

Windows Defender smartscreen filter

You’ll also find built-in parental controls, for limiting and monitoring internet usage. You’re able to limit the amount of time spent online, restrict app usage by age group, and block specific websites from being accessed. Again, this sadly only works with Microsoft Edge browser – which renders it quite useless if you have other browsers installed on your machine.

However, Microsoft did release official browser extensions to support Chrome and Firefox – it brings the functionality of Windows Defender Application Guard to those browsers, protecting you from malicious links. However, installing these extensions can feel like a bit of a hassle. Users need to enable the Windows Defender Application Guard companion app from Microsoft Store, then install the extensions. Honestly, it feels like a lot of extra clicks to enable something which essentially operates off a blacklist, and launches suspicious websites in a sandboxed version of Microsoft Edge.

There are no suites or tiered subscriptions in Windows Defender Antivirus. It is simply one product that comes with Windows 8 / 10, and is entirely free.

Avast Antivirus

Avast Free 2019

Avast has long been in the computer security scene, co-founded in 1988 by two software engineer and security specialists. Avast was in fact the very first antivirus product available for Windows 95 OS, and as of today, has over 435 active subscribers. The company itself is worth upwards of $2 billion USD.

Avast offers many products for Windows, Mac, and Android operating systems. Their most basic protection comes in Avast Free Antivirus, which as the product name suggests, is entirely free. Users can upgrade to optional tiered subscription plans, with each tier offering additional features. Let’s take a look at each product available from Avast, and an overview of them.

Avast Products List

Avast currently offers a different lineup of products for Windows, Mac, and Android operating systems.

1. Avast Free Antivirus (Windows)
2. Avast Pro Antivirus (Windows)
3. Avast Internet Security (Windows)
4. Avast Premier (Windows)
5. Avast Ultimate (Windows)
6. Avast Security (Mac)
7. Avast Security Pro (Mac)
8. Avast Antivirus – Mobile Security & Virus Cleaner (Android)
9. Avast Passwords (Android)
10. VPN SecureLine by Avast – Security & Privacy Proxy (Android)

Avast Free Antivirus

To start, Avast Free Antivirus is quite an exceptional product. It offers most security features you would expect in an antivirus software, yet also offers a handful of useful tools at no additional cost. Some of these tools are typically found in premium versions of other antivirus products, so Avast’s free offering is actually pretty generous.

With Avast Free Antivirus, it offers multiple scan types (smart scan, full scan, boot-time scan) – the latter being the same thing as Windows Defender’s “offline scan”. The scans operate quickly and have relatively low system performance, though we’ll look at that later in this article.

You’ll be protected from the most common threat types such as spyware, ransomware, and traditional viruses and Trojans. The additional free tools include a WiFi Inspector, which will inspect your network for vulnerable settings and intrusion points.

A password manager will encrypt and store your passwords in a safe vault, and a Rescue Disk utility, which allows you to create a bootable USB drive (or CD) that will perform a very deep scan, incase you are infected with something that cannot be removed while Windows OS is running. Finally, it also offers email client protection.

For minimal performance impact, you can toggle Gaming Mode, with shuts off all notifications and consumes less background resources. On modern computers, the “performance saving” is highly negligible, so its more for annoying notifications while you’re full-screen gaming.

To enhance protection in your browser, you can also install their browser extensions – Avast Online Security, and Avast SafePrice. The first will warn you if you’re navigating a dangerous website, and blocks known phishing websites. The second compares product prices from several online shopping websites, to help you find the best deal. We suppose that’s more wallet protection than computer protection.

In any case, those extensions are available for Google Chrome, Mozilla Firefox, Opera, and possibly others.

As a basic yet powerful antivirus software, you could hardly go wrong with Avast Free Antivirus, when compared to even premium products from other companies. However, because Windows Defender Antivirus is also free, should you replace it with Avast Free Antivirus, or even one of Avast’s paid products? Later in this article, we’ll look at independent lab results, to see which one offers the best protection to answer that.

One thing to be said for Avast Free Antivirus though is that it does offer the free additional tools (WiFi Scanner, password storage, etc.) which Windows Defender does not. Let’s continue looking at Avast’s other products.

Avast Pro Antivirus

The first subscription tier for Avast Antivirus is Pro, which is offered at a single-machine license for $40 per year. You can also purchase in license packs – $55 will get you licenses for 3 computers, and $85 for 5 licensers. The discount continues up to $14 per license, if you purchase licenses 10 at a time.

Avast Pro contains all of the same features found in Avast Free, with only one extra inclusion. This is the Avast Safezone, which is a sandbox browser, used for running programs in an isolated environment. It creates a desktop isolation by opening a new desktop with no other applications running, and leaves no traces behind once its closed.

Applications opened in this sandbox have limited access to your computer files, which means malicious software will be unable to make permanent changes to your system, if somehow opened. It also has a Real Site verifier, which can protect your browser from hackers and malicious redirects to phishing websites.

Thus, the single additional feature of Avast Pro Antivirus is mainly useful for perhaps doing online shopping or entering personal data on websites. Whether this single feature is worth the cost of a yearly subscription, is entirely up to you.

Avast Internet Security

The next tier is Avast Internet Security, which costs $59.99 per year for a single machine license. This product contains all the features of Free + Pro, but also includes an advanced firewall, anti-spam filter, and additional ransomware protection.

Avast Premier + Avast Ultimate

The final two premium products, Avast Premier starts at $69.99 per year for a single license. It includes a data shredder, automatic software updates, and anti-spying protection for your webcam (Webcam Shield). You could save $69.99 per year by simply unplugging your webcam when its not in use, but most laptop webcams are built-in, so there’s that to consider.

Avast Ultimate, being the highest tier, offers all the features found in the tiers below it (of course), but it introduces a system cleanup utility, a VPN, and a premium password storage vault. The system cleanup utility scans your computer for junk files, and claims to optimize your system performance. There is, of course, a lot of debate over the efficiency and usefulness of registry cleaners and the like. The idea of “registry bloat” in based in theory, and very old versions of Windows, it’s pretty much a non-issue on Windows 10.

Thus, the system cleanup utility will probably do absolutely nothing for your computer’s performance, and it doesn’t offer anything you can’t already do in Windows for free. Even more ironic, the free program CCleaner, which also does all of this stuff, is actually owned by Avast (Avast acquired Piriform back in 2017).

The system cleanup utility is not worth the price of an Avast Ultimate upgrade whatsoever, but the VPN and premium password storage vault could be useful.

Avast Mac Products

There are only two products offered by Avast for macOS users. These are Avast Security, and Security Pro.

Avast Security for Mac

Like on Windows, Avast Security is a free product which provides a basic level of malware protection, a WiFi scanner for finding vulnerabilities in your network, and web / email shields. Upgrading to Avast Security Pro gives you ransomware protection, and a WiFi intruder alert.

Avast also offers individual tools for Mac users, which can be downloaded separately. These tools are individual versions of the tools you’d find in Avast’s products for Windows, such as Avast Passwords, Cleanup Pro, and SecureLine VPN. Each of these products have an individual price, but you can take them for a trial run.

Avast Android Products

Antivirus products are pretty much useless on the Android system, a fact antivirus software companies are aware of. Thus, the majority of antivirus products for Android do not focus so much on the “virus scanning” (though they’ll offer scanning functions), but on security tools, and upselling additional services.

Avast Mobile Security 2019

Avast’s mobile security app offers an app locker for protecting your apps from being opened (by prying girlfriends, of course), a call blocker, VPN, junk file cleaner, web shield, Wi-Fi security scanner, a private photo gallery, and if your Android phone is rooted, you can use Avast firewall.

Some additional features revolve around anti-theft measures. For example, if your phone is stolen, Avast mobile security will attempt to capture photo and audio recording of the thief, when they attempt to open your phone. You’ll also get a GPS-based last known device location, and it will automatically register your device as “lost” if the SIM card is changed.

The free version includes all of these tools, and is supported by video ads. If you don’t want video ads, you can upgrade to the Pro version to remove them.

All of the other Avast products for Android are just individual versions of the features found in the main product. So you could download Avast’s VPN, or password vault, if you don’t want the entire suite on your phone.

Avast vs Windows Defender Threat Protection

Both products use a signature-matching detection, which means they compare files against a database of signature malware threats. They also use heuristic analysis, to monitor the behavior of apps, and how they interact with your system. This allows antivirus software to catch previously unknown malware.

The independent testing lab AV-Test provides results for how well these two antivirus products stack up against each other, so let’s look at the results. The tests were done using Windows 10.

Windows Defender

AV-Test Windows Defender results

In AV-Test’s March 2019 report, Windows Defender was able to protect against 100% of zero-day (previously unknown) malware, which means its heuristic analysis is fantastic. That came as no surprise, as a built-in Windows product should know if an app is tampering with key Windows files. It’d be almost kind of hilarious if they failed in that department, right? In any case, the test was performed against 202 samples.

In subsequent testing using different samples in April 2019, Windows Defender once again scored a perfect 100% detection rate, giving Windows Defender a perfect score.


AV-Test Avast results April 2019

In the same set of tests, Avast consistently scored 99.9% in March, and 100% in April. This gives Avast a nearly perfect protection score of 5.5/6.0.

Windows Defender vs Avast PC Performance

For a comparison of how both products impact your computer performance, we will look at test results from both AV-Test and another independent lab, AV-Comparative. They look at the performance impact of the antivirus products by doing normal routine computer tasks, such as copying files, browsing websites, installing programs, and similar tasks.

For AV-Test, both products were awarded a ⅚ star rating. The test results are demonstrated in percentage of slowdown while performing typical computer results, as pictured below.

Windows Defender

AV-Test Windows Defender performance


AV-Test Avast performance

So at a glance, both excel and suffer in different areas. Avast had a larger performance impact during launching of applications, while Windows Defender impacted installation of programs more.

AV-Comparatives similar test showed a bit of a different story, as Avast was given the ADVANCED + award, while Windows Defender was only given STANDARD rating. Avast had an impact score of 8.9, whereas Windows Defender had a whopping 30.4. This in fact put Windows Defender has the 2nd worst impact of all the AV products tested by AV-Comparative; AdAware had the highest impact of all products tested.

What’s worth noting is that if you’re on a high-end system, the “performance impact” we’re talking about probably differs in milliseconds or a couple seconds at most, for launching programs and similar. This is pretty negligible stuff, so neither products should significantly slow your computer.

Avast vs Windows Defender, Final Words

Deciding on which of these two antivirus products to use is no easy task, but if we had to choose, we are leaning towards Avast.

For starters, if we compare Avast’s free, basic protection to Windows Defender, Avast performs a bit better in malware detection, performance impact, and the free additional tools beyond scanning and malware protection that come with Avast Free Antivirus.

The only edge we could give to Windows Defender, as far as comparison of free products goes, is Windows Defender firewall being native built into Windows. That certainly saves the user the headache of disabling Windows built-in firewall to enable a firewall from an AV product.

Once we start comparing Avast’s premium products to Windows Defender, it’s a no contest. Because there are no premium products and additional premium features found in Windows Defender, then Avast only gets better than Windows Defender as you go up in the tiers.

Finally, Avast’s browser extensions are actually quite useful, and available for a handful of browsers. Windows Defender’s browser extension is native for Microsoft Edge, and enabling it for other browsers is a bit of a headache, and doesn’t really offer much additional protection.

Winner: Avast

If you’re looking for more antivirus comparisons, check out our Bitdefender versus Avast guide.

Advertiser Disclaimer: We are a professional review site that receives compensation from the companies whose products we review. We test each product thoroughly and give high marks to only the very best. We are independently owned and the opinions expressed here are our own. We are not responsible for direct, indirect, incidental or consequential damages resulting from use of any antivirus software and/or this website.