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1Fix the driver behind crashes, sound loss and screen glitches2Clear out junk files and repair common Windows errors3Scan for outdated or missing drivers - takes under a minuteIn the Android antivirus tests covered here, Bitdefender Mobile Security, Kaspersky Internet Security and Norton 360 tied for the strongest repeated AV-TEST scores in 2021: each earned 6/6 for protection, performance and usability in March, May, September and November. That makes them defensible leaders in those rounds—not a unique winner, and not a guide to which app performs best today.
AV-Comparatives’ separate review examined apps taken from Google Play in June 2021 and described features for Android 10. The dates and versions matter: these are historical results, not evidence about current app builds or newer Android releases.
Which Android antivirus scored best in 2021?
Bitdefender Mobile Security, Kaspersky Internet Security and Norton 360 shared the top marks across four AV-TEST rounds. In each round, all three scored the maximum 6/6 in protection, performance and usability. Because their results were tied, these tables do not establish that one was better than the others.
AV-TEST awarded up to 6 points in each of three categories, for a maximum of 18. Protection measured detection of malware; performance assessed impact on the device; and usability covered issues such as false alarms. AV-TEST said an app needed at least 10 points overall to earn its seal of approval. These are category scores, not percentages.
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| AV-TEST round | Bitdefender Mobile Security | Kaspersky Internet Security | Norton 360 |
|---|---|---|---|
| March 2021 | Version 3.3; protection 6/6, performance 6/6, usability 6/6 | Version 11.65; protection 6/6, performance 6/6, usability 6/6 | Version 5.3; protection 6/6, performance 6/6, usability 6/6 |
| May 2021 | Version 3.3; protection 6/6, performance 6/6, usability 6/6 | Version 11.67; protection 6/6, performance 6/6, usability 6/6 | Version 5.7; protection 6/6, performance 6/6, usability 6/6 |
| September 2021 | Version 3.3; protection 6/6, performance 6/6, usability 6/6 | Version 11.70; protection 6/6, performance 6/6, usability 6/6 | Version 5.16; protection 6/6, performance 6/6, usability 6/6 |
| November 2021 | Version 3.3; protection 6/6, performance 6/6, usability 6/6 | Version 11.76; protection 6/6, performance 6/6, usability 6/6 | Version 5.21; protection 6/6, performance 6/6, usability 6/6 |
Sources: AV-TEST March 2021, May 2021, September 2021 and November 2021.
What the longer AV-TEST endurance test found
AV-TEST’s January–June 2021 endurance test used two malware test sets. Bitdefender, NortonLifeLock, G DATA, McAfee and Trend Micro detected all attackers in both sets. Avast, AVG and Kaspersky each detected 99.9% in the real-time test and 100% on the reference set. Google Play Protect detected 68.8% in real time and 76.6% on the reference set. Nine of the 15 tested apps achieved 18/18 overall.
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These percentages describe the lab’s test sets and test period; they are not promises of protection against every threat a person might encounter. Kaspersky’s small difference in the real-time result is consistent with the separate AV-TEST category tables showing it tied at the maximum in the four listed rounds.
See AV-TEST’s 2021 endurance-test report.
How Google Play Protect compared
Google Play Protect is Android’s built-in comparison point. In the March, May, September and November 2021 AV-TEST tables, it repeatedly scored 0/6 in protection, while its performance and usability scores varied by round. The endurance test likewise recorded lower detection percentages than those of the named commercial products. This is a comparison of results from those specific 2021 tests, not a claim about later versions or present-day performance.
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What the June 2021 feature review can—and cannot—tell you
AV-Comparatives evaluated products obtained from Google Play in June 2021. Its feature overview applies to Android 10, and its report lists capabilities such as anti-malware, anti-theft, safe browsing, app lock and app audit. Availability and implementation differed by product, so a feature should not be assumed present in every app simply because it appears in the review.
The evaluation included 3,568 unique malicious applications, tested on 8 June 2021 using genuine Android smartphones. Those details provide context for the test rather than a guarantee about an individual phone, a later app version or a newer Android release. Read AV-Comparatives’ Mobile Security Review 2021 for its product overview and methodology.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.How to interpret the comparison
- For lab results: the three repeated AV-TEST leaders were Bitdefender, Kaspersky and Norton; the reported scores show a tie, not a ranked winner.
- For features: use the June 2021 AV-Comparatives overview as a dated Android 10 snapshot, and verify the app’s current feature list before relying on a specific capability.
- For a present-day choice: do not treat 2021 scores, software versions or feature symbols as current advice. The evidence here does not establish today’s app performance, pricing, subscription terms or regional availability.
AV-Comparatives cautioned that “The perfect mobile security product for all devices and all users does not exist.” A suitable choice depends on what features a user needs and the device in question.
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