Microsoft 365 Plans Compared (2026): Business vs Enterprise

Microsoft 365 is no longer a single product — in 2026 it is a family of plans ranging from web-only office tools for small teams to enterprise-grade security and compliance suites used across large organizations. Choosing the wrong tier means overpaying for features you will never use, or missing critical tools your team depends on. This guide compares every major plan — Business Basic, Business Standard, Business Premium, E3, and E5 — so you can make the right call and buy your license key before the July 2026 price adjustment takes effect.

Quick Pick: Plans Available on Instant Key

Microsoft 365 Plan Comparison (2026)

Columns highlighted in blue = plans available to purchase on Instant Key.

Business Plans (up to 300 users)

Business Basic covers web and mobile versions of Word, Excel, PowerPoint, and Outlook — but no desktop apps. It suits teams whose workflow is primarily browser-based and who do not depend on locally installed Office software or advanced security features.

Business Standard adds the full desktop Office suite across up to 5 devices per user, making it the right choice for teams that rely on advanced Excel features, offline editing, or professional-grade Outlook. It also includes Microsoft Bookings, Forms, and the Webinar tier of Teams.

Business Premium is the most complete SMB plan. On top of everything in Standard, it adds Microsoft Intune for device management, Microsoft Defender for Business, and Azure AD Premium P1 for conditional access — tools that are normally sold separately as enterprise add-ons. For any organization that handles sensitive client data or operates in a regulated sector, Business Premium is the responsible choice. Buy Microsoft 365 Business Premium at Instant Key.

Enterprise Plans (unlimited users)

E3 lifts the 300-seat cap and adds enterprise-grade compliance: unlimited mailbox archive, in-place eDiscovery, litigation hold, and advanced data loss prevention. It targets legal, finance, and healthcare organizations where data retention and audit trails are mandatory. OneDrive storage becomes unlimited. Buy Microsoft 365 E3 at Instant Key.

E5 sits at the top of the stack, adding Microsoft Defender for Endpoint Plan 2, Microsoft Sentinel SIEM, Microsoft Purview advanced information protection, Power BI Pro, and Phone System. It is primarily for large enterprises with a dedicated security operations centre or advanced analytics requirements.

Which Plan Is Right for Your Team?

Not sure whether Microsoft 365 or Office 2021 is right for your situation? Read: What is the difference between Microsoft 365 and Office 365?

Frequently Asked Questions

What is the difference between Microsoft 365 Business and Enterprise plans?

Business plans (Basic, Standard, Premium) are capped at 300 users and focus on productivity and foundational security. Enterprise plans (E3, E5) have no user cap and add enterprise-grade compliance, unlimited archive, eDiscovery, and — at E5 — advanced threat protection and analytics. If your organization has more than 300 seats or formal compliance obligations, Enterprise is the right tier.

Is Microsoft 365 Business Premium enough for a team that handles sensitive data?

For most SMBs, yes. Business Premium includes Microsoft Intune for device management, Microsoft Defender for Business, and Azure AD Premium P1 for conditional access. It covers the key requirements for cyber insurance and many industry compliance frameworks. Organizations with formal eDiscovery or legal hold obligations should consider E3 instead.

Will Microsoft 365 prices increase in July 2026?

Microsoft has confirmed further price adjustments across its commercial plans for 2026. Purchasing a license key through a reseller like Instant Key before the effective date can lock in current pricing for the subscription term.

What is the difference between Microsoft 365 E3 and E5?

E3 provides full enterprise compliance, unlimited archive, eDiscovery, and core enterprise identity management. E5 adds Microsoft Defender for Endpoint Plan 2, Microsoft Sentinel SIEM integration, Microsoft Purview advanced information protection, Power BI Pro, and advanced Phone System. E5 is primarily for organizations with a dedicated security operations centre or complex analytics requirements.

Can I still buy Office as a one-time purchase instead of a subscription?

Yes. Microsoft Office 2021 is available as a perpetual one-time license for 1 PC. It includes Word, Excel, PowerPoint, and Outlook permanently with no monthly fee. It does not include cloud storage, Teams, or feature updates beyond security patches.

How quickly does Instant Key deliver the license key?

Delivery is instant — your license key is sent by email within 15 minutes of payment confirmation. All keys sold by Instant Key are sourced from third-party suppliers.