Microsoft 365 Business Premium already includes Microsoft Defender for Business, Defender for Office 365 Plan 1 and Entra ID P1, and the Defender Suite for Business Premium is a $10 per user per month add-on that upgrades them to Microsoft's enterprise versions. As of October 2026 it's billed yearly, requires Business Premium and covers up to 300 users, which gets a Business Premium tenant close to E5 security without the E5 bill. For firms with regulated data, someone watching alerts, or an insurer asking hard questions, it's worth it.
For a 12-person office with nobody reading the alerts, it isn't. Not yet.
The short version:
- $10 per user per month on top of Business Premium's $22, for firms of 300 users or fewer.
- It upgrades your endpoint, email, and identity protection to Microsoft's enterprise versions.
- Buy it once Business Premium is fully configured and someone is assigned to act on alerts.
Which Microsoft Defender comes with Business Premium?
Business Premium includes Microsoft Defender for Business for laptops, desktops and phones, plus Defender for Office 365 Plan 1 for email. Defender for Business isn't a stripped-down antivirus. Microsoft's Defender for Business overview says it carries the features of Defender for Endpoint Plan 1 plus some from Plan 2, and the gap to the Plan 2 you get in the Defender Suite is narrower than most people expect:
| Capability | Defender for Business (in Business Premium) | Defender for Endpoint P2 (in the Defender Suite) |
|---|---|---|
| Next-generation antivirus and attack surface reduction | Yes | Yes |
| Endpoint detection and response | Yes, simplified for small teams | Yes |
| Automated investigation and remediation | Yes | Yes |
| Automatic attack disruption | Yes | Yes |
| Core vulnerability management | Yes | Yes |
| Advanced hunting over 30 days and six months of data retention | No | Yes |
| Microsoft Threat Experts | No | Yes |
| Windows and Linux servers | Extra license | Extra license |
So the endpoint upgrade is mostly about investigation depth. The bigger jumps in the suite are Defender for Identity and the Entra ID P2 features, risk-based sign-in policies and Privileged Identity Management, which Business Premium doesn't include at all.
What is the Defender Suite for Business Premium?
It's an annual add-on that layers Microsoft's enterprise security tools on top of Business Premium. Microsoft lists it at $10.00 per user per month, paid yearly, and it requires an existing Business Premium subscription. It's built for organizations with 300 users or fewer, the same cap as Business Premium itself.
Microsoft sells three versions, all on its SMB security add-on pricing page:
- Defender Suite: $10 per user per month. Threat protection.
- Purview Suite: $10 per user per month. Data protection and compliance.
- Defender and Purview Suites together: $15 per user per month.
What's actually in the box?
Microsoft lists seven components in the Defender Suite:
- Microsoft Entra ID P2. Risk-based sign-in policies and Privileged Identity Management.
- Microsoft Defender XDR. One console that ties the other alerts together.
- Defender for Endpoint P2. The enterprise EDR, with advanced hunting.
- Defender for Office 365 P2. Adds automated investigation and attack simulation training.
- Defender for Identity. Watches on-premises Active Directory for attacks.
- Defender for Cloud Apps. Shows which SaaS apps staff use and lets you block the risky ones.
- Defender for IoT, Enterprise IoT. Visibility into printers, cameras, and other network devices.
Business Premium already includes Defender for Business, Defender for Office 365 Plan 1, and Entra ID P1. So the suite doesn't give you protection you had none of. It upgrades what you have to the versions large companies run.
What does it cost next to E5?
Here's the math at Microsoft's US list prices as of October 2026, paid yearly. Microsoft 365 E5 went from $57 to $60 on July 1, 2026, while Business Premium stayed at $22, according to Microsoft's 2026 pricing update:
- Business Premium alone: $22 per user
- Business Premium plus Defender Suite: $32 per user
- Business Premium plus both suites: $37 per user
- Microsoft 365 E5: $60 per user
That's a $23 gap per user per month between Premium plus both suites and E5. For a 50-person firm, it's $13,800 a year.
E5 does include things the suites don't, like Power BI Pro, and it has no 300-user cap. If you'd buy those anyway, run the numbers both ways. If you wouldn't, the suites win on price.
Who should buy it?
Buy it if at least one of these is true:
- Someone watches the alerts. An in-house IT person with time, or a managed detection and response provider. Advanced hunting with nobody hunting is a waste of $10.
- You still run on-premises Active Directory. Defender for Identity is the piece most small firms have no substitute for, and identity attacks against a domain controller are how ransomware crews take over a network.
- You have more than one or two admin accounts. Entra ID P2 adds Privileged Identity Management, so admin rights are granted for an hour instead of forever. We cover the trade-offs in Entra ID P1 vs P2.
- Your insurer or regulator wants EDR evidence. Defender for Endpoint P2's longer device timeline makes it easier to answer "what happened on this machine?" after an incident.
Who should skip it?
Skip it if Business Premium isn't configured yet. A lot of tenants run Premium at a fraction of what it already does: Conditional Access not built, Defender for Business onboarded on half the laptops, Intune enforcing nothing.
Paying $10 more per user doesn't fix that. It adds more unread alerts on top of the unread alerts you already have.
Skip it, too, if you already pay for a third-party EDR you're happy with. Defender for Endpoint P2 and CrowdStrike or SentinelOne doing the same job on the same laptop is double spending. Our Defender for Business vs CrowdStrike vs SentinelOne comparison walks through that choice.
Is the Purview Suite worth adding?
Only if you have a compliance reason. The Purview Suite covers data loss prevention, sensitivity labels with automatic classification, retention and records management, and insider risk detection.
That matters for an RIA facing SEC recordkeeping rules, a medical practice under HIPAA, or a law firm with client confidentiality obligations. A marketing agency with no regulated data can leave it on the shelf.
If you need both, buy the combined $15 bundle. Two separate $10 suites cost $5 more per user for the same thing.
How to roll it out without wasting the money
- Finish Business Premium first. Conditional Access, MFA everywhere, every device in Intune, Defender for Business on every endpoint.
- Decide who reads the alerts. Name the person or the provider before you buy.
- Start with the pieces that close your biggest gap. For most firms that's Defender for Identity if you have a domain controller, or Privileged Identity Management if you don't.
- Turn on Cloud Apps discovery. It'll show you every SaaS app your staff signed up for. The list is always longer than you think.
- Review in 90 days. If nobody's acted on what the tools found, you're paying for a dashboard.
Our Microsoft 365 security team handles this sequence for clients, and our managed detection and response service covers the "who reads the alerts" question.
Frequently asked questions
Is Microsoft Defender for Business included in Business Premium?
Yes. Business Premium includes Defender for Business for up to 300 users. Firms on Business Basic, Business Standard or Office 365 E1 can buy Defender for Business as a standalone subscription instead, per Microsoft's overview, but they still won't qualify for the Defender Suite, which requires Business Premium.
Does Defender for Business protect servers?
Not on the Business Premium license alone. Microsoft says protection for Windows and Linux servers is available but needs extra licenses, and the same is true with Defender for Endpoint P2 in the suite. Count your servers before you compare quotes.
Can I buy the Defender Suite without Business Premium?
No. Microsoft lists Business Premium as a prerequisite for all three add-ons.
If you're on Business Standard, you'd upgrade to Premium first, then add the suite. Firms on Microsoft 365 E3 have a different path: the enterprise Microsoft Defender Suite, which Microsoft lists at $12.00 per user per month as of October 2026, or a full move to E5.
Is there a user limit?
Yes. Microsoft says the Defender Suite is built for organizations with 300 users or fewer, matching the Business Premium cap. Past 300 users, you're into enterprise licensing, where E5, or E3 plus the enterprise Microsoft Defender Suite, are the equivalents.
Does the Defender Suite replace an MDR provider?
No. It gives you better tools, not people.
The suite surfaces more threats and more detail, and someone still has to investigate them, often at 2 a.m. That's the job an MDR provider or an in-house security analyst does.
Do I have to buy it for every user?
Yes, in practice. Microsoft sells it per user, and partial coverage leaves the gap an attacker needs: one unprotected mailbox or laptop.
If you're tempted to license only part of the staff, confirm the licensing terms with your Microsoft partner first.
Is the Defender Suite the same as Microsoft 365 E5 Security?
Close, but there are now two Defender Suites. Microsoft renamed the E5 Security add-on for enterprise plans to Microsoft Defender Suite, according to its plan comparison. As of October 2026, its Defender for Endpoint page lists that suite at $12.00 per user per month, paid yearly, and it requires Microsoft 365 E3, or Office 365 E3 with Enterprise Mobility + Security E3.
The version this article covers is a separate $10 product, Microsoft Defender Suite for Microsoft 365 Business Premium, capped at 300 users. You buy the one that matches the plan you already own.
Find out if you're ready for it
The right answer depends on how much of Business Premium you're actually using today. Book a complimentary Microsoft 365 security assessment and we'll tell you whether the Defender Suite closes a real gap in your tenant or just adds another dashboard nobody opens.
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