Microsoft 365 Business Premium vs E3: Which License Fits Your Business?
Here’s the short version: if your organization has fewer than 300 users, Microsoft 365 Business Premium is the better fit for most businesses — it costs less per seat and, surprisingly, includes stronger email and endpoint security than E3 does out of the box. Microsoft 365 E3 is the right choice when you’re past 300 seats, need 100GB mailboxes and litigation hold, require Windows Enterprise, or face eDiscovery and retention obligations Business Premium can’t satisfy.
Microsoft adjusts licensing often enough that we won’t quote prices here — check current pricing — but the gap is real: E3 costs meaningfully more per user per month, and that premium buys real capabilities. Just not always the ones people assume. One note before we compare: Equal Tech Solutions is vendor-neutral. We license, deploy, and support both plans for clients, so there’s no thumb on the scale here.
What both plans include
The core is identical, which is exactly why the decision confuses people. Both give you:
- Desktop Office apps (Word, Excel, PowerPoint, Outlook) plus web and mobile versions
- Exchange Online email, SharePoint, and OneDrive
- Entra ID P1, which means Conditional Access — the backbone of a modern identity perimeter
- Intune for device management and compliance policies
- Data loss prevention and sensitivity labels
Whichever you pick, the identity and device management foundation is the same.
Where E3 pulls ahead
- No seat cap. Business Premium stops at 300 licensed users. E3 scales as far as you need.
- Bigger mailboxes. E3 includes Exchange Online Plan 2: 100GB mailboxes with auto-expanding archives, versus 50GB on Business Premium.
- Litigation hold and eDiscovery. Exchange Plan 2 brings litigation hold, and E3 adds Purview eDiscovery with broader retention options. If legal ever tells you to preserve a departed employee’s data, this is the tier where that’s straightforward.
- Windows 11 Enterprise. E3 carries Enterprise upgrade rights and the management features some security baselines and virtual desktop setups require.
- OneDrive expansion. E3 tenants can extend individual OneDrive storage beyond the 1TB default; Business Premium caps at 1TB per user.
One catch worth knowing: Microsoft now sells new enterprise suites without Teams in most markets — it’s a separate line item. Business Premium still includes Teams. Make sure any E3 quote you’re reviewing accounts for that.
Where Business Premium quietly beats E3
This is the part that surprises people. Business Premium includes Defender for Business, which delivers full endpoint detection and response: behavioral detection, automated investigation and remediation, attack surface reduction. E3 includes Defender for Endpoint Plan 1, which covers next-generation protection but not the EDR and automated remediation layer. For endpoint security, the cheaper license is the stronger one.
Same story for email. Business Premium includes Defender for Office 365 Plan 1 — Safe Links, Safe Attachments, impersonation protection. E3 doesn’t include Defender for Office 365 at all; you buy it as an add-on or step up to E5. We’ve broken down that whole stack in our guide to the Business Premium security you’re already paying for, so we won’t repeat it here — the point is that an E3 tenant without add-ons has weaker phishing protection than a Business Premium one.
The 300-seat cap in practice
The cap applies to Business Premium seats, not to your tenant. You can mix licenses freely, and the most common pattern we deploy looks like this: Business Premium for the bulk of staff, with E3 assigned only to the people who need it — executives and legal for litigation hold and large mailboxes, or a records team that needs deeper Purview tooling. Growing past 300 doesn’t force everyone onto E3 on day one, either; seats beyond the cap go enterprise while everyone else stays put.
How to decide
- Under 300 users, no formal eDiscovery obligations: Business Premium. You’ll pay less and get better default security.
- Regulated, litigious, or archive-heavy: E3 — but budget for the Defender for Office 365 add-on, or your phishing protection will trail the cheaper plan’s.
- Growing past 300: mix. Move the users who need enterprise features first.
- Already on E3 with fewer than 300 seats: get a licensing review. Plenty of businesses pay E3 rates for capabilities Business Premium covers, while missing security features it includes.
Licensing is one of the few places in IT where the right answer can cut cost and improve security at the same time. Equal Tech Solutions handles Microsoft 365 licensing, migration, and security configuration for businesses across Cleveland, Chattanooga, and the Southeast US, and a review of your tenant usually pays for itself. Contact us and we’ll map your actual needs to the right license mix.
