Bitdefender vs Microsoft Defender: is GravityZone worth paying for?
By Jean Luc Poitier, SEO and growth marketing strategist · Bitdefender Reviews · Updated October 1, 2026
Disclosure: this site reviews Bitdefender GravityZone and earns a commission if you sign up for it through our links. We earn nothing from Microsoft Defender. The figures below come from each company's own pages and the test labs, with the dates checked.
If you already pay for Microsoft 365 Business Premium, start with the Defender for Business you own. It includes EDR, it is light on PCs, and it protects well. Paying for GravityZone on top makes sense only for a specific reason.
The reasons are real, though. GravityZone was compromised 3 times to Defender's 29 in three years of AV-Comparatives business tests. One license covers servers, the trial needs no card, and the console can run on-premises. If you don't have Business Premium, GravityZone costs about the same per device as standalone Defender for Business.
Bitdefender vs Microsoft Defender at a glance
| Compared on | Bitdefender GravityZone | Microsoft Defender for Business |
|---|---|---|
| Price | $324.99/yr for 10 devices (Small Business Security) | $3 per user/month ($36/yr), up to 5 devices per user |
| Included in | Sold on its own | Microsoft 365 Business Premium ($22 per user/month) |
| EDR | From Business Security Enterprise (quote only) | Included at $3 |
| Servers | Count as devices (up to 30% on Small Business Security) | Separate add-on, one per server, max 60 per subscription; price not on Microsoft's page |
| User limit | 1 to 100 devices online; more through partners | Up to 300 users; Defender for Endpoint above that |
| Free trial | About 30 days, no card | 1 month, card required; converts to paid automatically |
| Console | Cloud or on-premises | Cloud; devices need internet access |
| AV-Comparatives Business Security, 2023-2025 (2,901 cases) | 3 compromised, 11 false alarms | 29 compromised, 14 false alarms |
| AV-Comparatives performance, 2025 (lower is better) | 32.8 and 26.5 | 13.8 and 13.7 |
| AV-TEST business, Dec 2025 | 17.5 of 18 (protection 6/6) | 18 of 18 (protection 6/6) |
| MITRE Managed Services 2024 | 40 of 43 detections actionable, 82 alerts | 27 of 43 actionable, 385 alerts |
| PeerSpot | Business Security 4.3/5 (16 reviews) | Defender for Business 3.8/5 (20); Defender for Endpoint 4.1/5 (212) |
Figures checked against each company's published pages and review-platform listings as of 2026-10-01. “Not published” means the company does not publish that figure.
Price, and what you may already own
Microsoft sells Defender for Business at $3 per user per month, billed yearly, for up to 300 users with up to 5 devices each. It is also part of Microsoft 365 Business Premium at $22 per user per month, a price Microsoft left unchanged in its July 2026 increases. If your staff are on Business Premium, you have it already.
For 10 people with one computer each, standalone Defender for Business costs $360 a year and GravityZone Small Business Security $324.99. Defender gets cheaper per device if people have several. Servers change the sums: Defender for Business needs a separate servers add-on for each Windows or Linux server, capped at 60 per subscription, and Microsoft's page doesn't list its price. GravityZone counts a server as a device.
Microsoft's trial needs a card and turns into a paid subscription after a month; after that, you have 7 days to cancel for a prorated refund. GravityZone's trial needs no card, and first online orders have 30 days for a refund.
Protection and performance in lab tests
AV-Comparatives tests Microsoft Defender Antivirus (managed through Intune) next to GravityZone twice a year. Across the six reports from 2023 to 2025, Defender was compromised 29 times and GravityZone 3 times, in 2,901 real-world cases. In the 2025 rounds the gap was 9 to 2 (latest report). Defender scored 100% in the lab's August to November 2025 malware test, and AV-TEST has given it full protection marks in every business round through August 2026.
Defender is clearly lighter on the PC. Its impact scores in AV-Comparatives' 2025 performance tests were 13.8 and 13.7 against GravityZone's 32.8 and 26.5. If your fleet has older machines, that matters, and GravityZone's reviewers mention slowdowns on older PCs too.
Management, servers, and support
Defender's strength is the Microsoft stack: the same identities, Intune device management, and email security, with automatic attack disruption across them. Its reviewers' main complaints are the portals and support:
“We have had issues where the urgency level of the Microsoft support is not as high as ours, especially during a data breach or potential data breach situation.”Robert Arbuckle, PeerSpot, November 2025
“sometimes there's moving around to different spots and it's a little hard to navigate”Scott Sprague, PeerSpot, November 2025
GravityZone has one console for workstations and servers and can run it on your own servers; Microsoft says Defender devices need internet access. GravityZone's reviewers complain about the console and slow support too, so neither side wins on service. In MITRE's 2024 managed services evaluation, Bitdefender's analysts sent 82 alerts and Microsoft's 385, with more of Bitdefender's marked actionable (40 of 43 detections against 27).
Keeping security separate from Microsoft
Some buyers want their security vendor to be different from the company that runs their email and identity. The US Cyber Safety Review Board's 2024 report on the Storm-0558 intrusion into Microsoft's cloud email called it preventable. That is a judgment about Microsoft's cloud, not about Defender's detection, but it is why some IT teams keep a second vendor in the stack.
Where Microsoft Defender wins
- Already included in Microsoft 365 Business Premium, so many small businesses pay nothing extra.
- EDR and automatic attack disruption in the $3 tier.
- Much lighter on PCs in AV-Comparatives' 2025 performance tests.
- Full protection marks in every AV-TEST business round through August 2026, and 100% in AV-Comparatives' late-2025 malware test.
- One identity, device management, and email stack with Intune and Entra.
- Covers up to 5 devices per user, which is cheap for staff with a laptop, phone, and tablet.
Who should pick Bitdefender GravityZone
Businesses that aren't on Business Premium, that want the stronger AV-Comparatives protection record, that run servers and want one license for everything, or that need an on-premises console or a vendor separate from Microsoft. See GravityZone pricing or read what 110+ users say.
See Bitdefender GravityZone pricingBitdefender vs Microsoft Defender FAQ
Is Microsoft Defender good enough for a small business?+
Often, yes. If you already pay for Microsoft 365 Business Premium, Defender for Business is included, with EDR, and it protects well in lab tests. Businesses pick GravityZone over it for stronger results in AV-Comparatives' business tests, simpler server licensing, an on-premises console option, or to keep security separate from their email and identity vendor.
Is Bitdefender or Microsoft Defender cheaper?+
It depends what you already own. Defender for Business costs $3 per user per month ($36 a year), covering up to 5 devices per user, and is included in Microsoft 365 Business Premium ($22 per user per month). GravityZone Small Business Security costs $324.99 a year for 10 devices. Servers need a separate Microsoft add-on; GravityZone counts them as devices.
Which protects better, Bitdefender or Microsoft Defender?+
In AV-Comparatives' Business Security Tests from 2023 to 2025 (2,901 real-world cases), GravityZone was compromised 3 times and Microsoft Defender 29 times. Defender scored 100% in the lab's late-2025 malware test and 6 of 6 for protection in every AV-TEST round through August 2026. Both are strong; GravityZone was stronger in AV-Comparatives' real-world tests.
Does Microsoft Defender slow computers down less than Bitdefender?+
Yes, in recent tests. In both 2025 AV-Comparatives performance tests, Defender had a much lower impact score (13.8 and 13.7) than GravityZone (32.8 and 26.5); lower is better.
Can Microsoft Defender protect air-gapped networks?+
Microsoft's documentation says Defender for Endpoint devices need internet connectivity, directly or through a proxy. GravityZone can run its console on your own servers, which suits isolated networks.