Microsoft 365 Business Premium vs E3 vs E5: security features compared for SMBs

Licensing is where security recommendations meet budgets. "Require compliant devices" or "use Privileged Identity Management" is only good advice if the tenant owns the feature, or if the customer understands what it would cost to get it. This comparison focuses on security and compliance capabilities; for productivity features, prices and the full terms, use Microsoft's own documentation.

At a glance

"Add-on" means the capability is available through a separate license (for example Microsoft Entra ID P2, or a security or compliance add-on) rather than included. Check which add-ons are currently offered for each base plan.

Identity: P1 vs P2

All three plans include Microsoft Entra ID P1, which is what most SMBs need first: Conditional Access, MFA on your terms, group-based access and self-service password reset with writeback. That makes the Conditional Access baseline possible on Business Premium and E3.

P2, included in E5, adds:

• Microsoft Entra ID Protection: user and sign-in risk, and Conditional Access policies that respond to it.
• Privileged Identity Management: just-in-time admin roles with approval and time limits. See Entra ID privileged access.
• Access reviews for guests, groups and roles.

A frequent pattern for smaller organizations is to buy P2 only for administrators, to get PIM for the accounts that matter most. Confirm the licensing requirements for each feature before recommending it.

Devices and endpoints

All three include Intune Plan 1 for enrollment, compliance, configuration, app protection and Windows Autopilot, which is enough for the Intune compliance baseline.

Endpoint protection is where the plans differ most:

• Business Premium includes Microsoft Defender for Business, designed for organizations up to 300 users, with next-generation protection, attack surface reduction, endpoint detection and response, and automated investigation and remediation.
• E3 includes Defender for Endpoint Plan 1: next-generation protection, attack surface reduction and device control, without the full EDR and automated investigation capabilities of Plan 2.
• E5 includes Defender for Endpoint Plan 2, with EDR, automated investigation, advanced hunting and threat analytics.

Microsoft's overview of Defender for Endpoint Plan 1 lists the details.

Email protection

Every Exchange Online mailbox is protected by Exchange Online Protection (anti-spam, anti-malware, basic anti-phishing). Beyond that:

• Defender for Office 365 Plan 1 (Business Premium) adds Safe Links, Safe Attachments and advanced anti-phishing, including impersonation protection.
• Plan 2 (E5) adds threat investigation and response tools, automated investigation and attack simulation training.
• E3 doesn't include Defender for Office 365; many E3 customers add it.

See Microsoft Defender for Office 365 overview. Whatever the plan, email authentication (SPF, DKIM and DMARC) is configured in DNS and costs nothing extra.

Data protection and compliance

Business Premium and E3 include the core Microsoft Purview capabilities most SMBs start with: sensitivity labels that users apply, data loss prevention, retention policies, Audit (Standard) and eDiscovery (Standard). E5 adds automatic labeling, Insider Risk Management, Communication Compliance, Audit (Premium) with longer retention and more events, and eDiscovery (Premium).

For regulated SMBs, the question is usually whether one or two of these (often longer audit retention or automatic labeling) justify an add-on, rather than a move to E5 for everyone.

Licensing details that catch people out

• Office 365 E3 is not Microsoft 365 E3. Office 365 E3 doesn't include Entra ID P1 or Intune. Check the exact SKU names in the admin center.
• Teams packaging. In many markets, Microsoft sells Enterprise suites with and without Teams. Check which versions the customer holds before comparing costs.
• The 300-seat cap. Business plans are capped at 300 users per plan; organizations near the cap need a plan for growth.
• Mixed licensing. Tenants can mix plans, but features apply per licensed user. A policy that relies on P2 doesn't protect users who only have P1.
• Owned but unused. The most common finding isn't a missing license; it's a Business Premium or E5 tenant whose Defender, Intune or Conditional Access features were never configured.

Choosing a plan: a practical approach

1. Start from the risks you found, not from the plan list. An assessment tells you whether the priority is identity, devices, email or data.
2. Use what's already owned. Configure existing licenses before buying new ones.
3. Close the biggest gap with the smallest change. For many SMBs on Business Standard, Business Premium closes identity, device and email gaps at once. For an E3 tenant with a strong endpoint tool, a targeted add-on may be enough.
4. Price it with Microsoft's current pricing or your distributor's price list; don't rely on figures from articles, including this one, which deliberately doesn't list prices.

Questions to ask in a licensing review

1. Which plan does each user actually hold, and are any users unlicensed for the security features your policies rely on?
2. Which included security features are configured, and which have never been turned on?
3. Are there unassigned licenses, or licenses on disabled and inactive accounts, that could fund an upgrade?
4. Does the organization run separate tools (endpoint protection, email filtering, backup) that overlap with what's already licensed? If so, is that deliberate?
5. Is the organization close to the 300-user Business plan limit, or growing toward it?
6. Do regulatory, insurance or customer requirements call for specific capabilities, such as longer audit retention or privileged access controls?

The answers usually point to one of three outcomes: configure what's owned, add a targeted add-on, or change plan for everyone. An assessment gives you the evidence for each.

Explaining licensing to customers

Customers rarely care about plan names; they care about outcomes. Translate each recommendation: "this plan lets us require that only your managed laptops can open company email" is clearer than "you need Entra ID P1 and Intune". Tie every licensing recommendation to a specific finding from the assessment, so it reads as fixing a known risk rather than an upsell.

How M365Assessments helps

M365Assessments reads the tenant's subscriptions and SKUs, license assignments and usage, and relates findings to what the tenant is licensed for, for example flagging Defender for Endpoint licensed with no devices onboarded, or unused seats. On MSP 50, MSP 100 and Enterprise plans, the Sales Guide also lists licensing opportunities alongside remediation projects. See M365Assessments for MSPs.