Bitdefender vs. Avast Free: Which AV Software Wins?

Bitdefender Antivirus Plus and Avast Free Antivirus are two popular antivirus suites that offer a lot of special features, but how do they stack up in a one-on-one showdown?

Illustration: Tom's Guide

Illustration: Tom's Guide

At first glance, many customers will choose Avast because it's free, but that doesn't take into account each product’s malware-detection skills and system-performance impact. To figure out which antivirus solution might be best for you, we've evaluated these factors using our own in-house testing and experiences, as well as tests done by independent labs.

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Bitdefender Antivirus Plus
Avast! Free Antivirus
$23.99 Bitdefender$Free
Zero-Day Malware Detection (Windows 10)
100 percent
99.4 percent
Widespread Malware Detection (Windows 10)
100 percent
99.9 percent
Online Malware Detection (Windows 7)
99.9 percent
99.6 percent
False Positives
System Impact
Lighter on Macs than PCs.Lighter on PCs than Macs.
Special Features
Password manager, network security scanner, secure web browser, game mode, virtual keyboard, file shredder
Password manager, network security scanner, secure web browser, game mode,

After six rounds of comparison, Bitdefender Antivirus Plus (starting at $39.99 per year) comes out with the win, thanks to its multiple perfect malware-detection scores, low system impact and ease of use.

MORE: Best Antivirus Software and Apps

PC Protection

Bitdefender Antivirus Plus and Avast Free Antivirus both detect and stop most malware preying on PCs, but the former edges past the latter.

In evaluations conducted by the Austrian testing lab AV-Comparatives from July to November of 2016, Bitdefender blocked an average of 99.9 percent of online malware, while Avast nipped  at Bitdefender’s heels with a rate of 99.6 percent. Avast registered 13 false positives -- benign programs or files mistakenly flagged as malware -- while Bitdefender registered none.

Bitdefender's scans earn high marks for practically perfect malware-detection rates.

Bitdefender's scans earn high marks for practically perfect malware-detection rates.

A similar pattern showed up in evaluations done during the same period by the German lab AV-TEST, which measured how well Bitdefender and Avast performed at detecting both known widespread malware and unknown “zero-day” malware. In both fields, Bitdefender excelled by small margins.

(Note: Both labs’ tests were conducted using Bitdefender Internet Security instead of Bitdefender Antivirus Plus. But as both use the same malware-detection engine, they would have earned the same scores.)

Bitdefender stopped 100 percent of both kinds of malware for Windows 10 and Windows 7. It dipped below perfection in only one round of Windows 8.1 tests, catching 98.7 percent of zero-day malware and 99.9 percent of widespread malware in December 2016. (It got them all in November.)

On Windows 10, Avast blocked all the zero-day malware in one round, but fell below that otherwise, stopping 98.8 percent of zero-day attacks in the previous round. It detected 99.9 percent of widespread malware in September 2016 and 99.8 percent in October. On Windows 8.1, Avast stopped 100 percent of zero-day malware in both rounds, while catching 99.8 percent of  widespread malware in November and 99.7 percent in December.

Avast got its worst score on Windows 7, catching 97.5 percent of zero-day malware in August but 100 percent in July. Avast's Windows 7 widespread-malware scores were better, at 99.9 percent in July and 99.8 percent in August.

Winner: Bitdefender Antivirus Plus. With zero false positives and the best detection, Bitdefender takes this round.

Mac Protection

When it comes to protecting Macs, your choice is a lot easier. AV-TEST's December 2016 test showed that Bitdefender detected 100 percent of malware attacking macOS Sierra, while Avast caught only 96.8 percent.

Winner: Bitdefender Antivirus Plus. When it comes to antivirus protection, what matters isn’t how much gets stopped, but how much gets through.

MORE: Best Antivirus Software for Mac - Tom's Guide

Ease of Use and Installation

Avast Free Antivirus and Bitdefender Antivirus Plus both make it easy to see messages saying that your system is safe, but they differ in the presentation. Bitdefender's home screen gives prominent placement to a toggle switch to enable Autopilot mode, which keeps a vigilant eye scanning your files. Avast places a "Run Smart Scan" button in the middle of  its home screen.

Bitdefender’s Quick-Scan button is also on its home page, but it’s jumbled among a bunch of other buttons and icons

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The installation processes for both programs are mostly the same, with one big difference:  Avast will try to install the Google Toolbar into your default web browser and change your browser home page to Google. To avoid this, you'll need to uncheck two small boxes at the bottom left corner of the first Avast installation screen.

Avast places its status message and scan button within easy reach.

Avast places its status message and scan button within easy reach.

Winner: Bitdefender Antivirus Plus. Avast needs to get its mitts off your default settings.

Special Features

Since you're actually paying for Bitdefender Antivirus Plus, it makes sense that it comes with features beyond superb malware detection. But you might be surprised how many freebies come with Avast's free offering.

The PC versions of Avast Free Antivirus and Bitdefender Antivirus Plus each offer a password manager, a network security scanner, a secured web browser for banking and shopping, a rescue-disk option for severely infected machines (drive not included) and a game mode to keep from interrupting your frag count.

Avast includes a password manager, which we don't even see in some paid options.

Avast includes a password manager, which we don't even see in some paid options.

While we expect to see at least some of those features on a paid offering, they're a pleasant surprise in the Avast Free Antivirus package. In fact, the only features that Bitdefender Antivirus Plus can lord over Avast Free Antivirus are a virtual keyboard (for those worried about keylogging malware) and a file shredder.

MORE: The Best (and Worst) Identity Theft Protection

Bitdefender and Avast both make you pay more for a firewall, either as a part of Avast Pro Antivirus ($49.99 per year) or with Bitdefender Internet Security (starting at $44.99 per year). At that price, Bitdefender throws in parental controls for keeping a child out of places where he or she shouldn't be looking, while Avast doesn't offer such options at any price.

Over on the Mac, neither Bitdefender Antivirus For Mac nor Avast Free Mac Security offer much in the way of special features.  

Winner: Tie. Bitdefender gives you a file shredder and virtual keyboard, but Avast offers a lot of goodies for free.

System Impact

Neither Bitdefender nor Avast will slow down your system much, but it might depend on the platform you use. When we tested both suites on an ASUS X555LA laptop running Windows 10, the Avast system exhibited a very light system impact, whereas the Bitdefender package created just a little more of a slowdown in  performance.

MORE: Which Laptop CPU is Right for You?

In testing on a MacBook Pro, the reverse was true: While both Bitdefender Antivirus for Mac and Avast Free Mac Security had a small impact on performance, the system running Bitdefender ran slightly faster.

Winner: Tie. Avast caused less system drag on PCs, but Bitdefender evens the score on Macs.


Bitdefender Antivirus Plus starts at a relatively low $39.99 per year for one PC, but Avast Free Antivirus is, well, free. For many buyers, that's going to be a first-round knockout. But since these products aren't quite the same, we can't stop there. Ultimately, it’s about what you’re getting for the money.

Winner: Avast! Free Antivirus. No price can beat free.


While it offers a surprising amount of features for being a free product, Avast Free Antivirus trails behind Bitdefender Antivirus Plus in malware detection, which is what really counts. 

The lack of a price tag on Avast Free Antivirus makes it an alluring choice for budget-minded consumers, and, yes, it is better than nothing (or Windows Defender). But Bitdefender Antivirus Plus is the better choice for anyone looking to batten down the hatches with antivirus protection.

Henry T. Casey
Managing Editor (Entertainment, Streaming)

Henry is a managing editor at Tom’s Guide covering streaming media, laptops and all things Apple, reviewing devices and services for the past seven years. Prior to joining Tom's Guide, he reviewed software and hardware for TechRadar Pro, and interviewed artists for Patek Philippe International Magazine. He's also covered the wild world of professional wrestling for Cageside Seats, interviewing athletes and other industry veterans.