Microsoft 365 Vs Office 2021 How To Choose The Right Product

Microsoft 365 vs Office 2021: How to Choose

Microsoft 365 is a subscription that gives you continuously updated Office apps, cloud storage, Teams, Exchange Online, and enterprise security. Office 2021 is a one-time purchase of desktop apps frozen at the 2021 feature set. For enterprises, Microsoft 365 is almost always the right choice — here is why.

Key differences at a glance

Category	Microsoft 365	Office 2021
Licensing model	Subscription (per user/month)	One-time purchase
Apps included	Word, Excel, PowerPoint, Outlook, Teams, OneNote, Access	Word, Excel, PowerPoint, Outlook, OneNote (no Teams)
Updates	Continuous feature updates via Current Channel	Security updates only (no new features)
Cloud services	Exchange Online, SharePoint, OneDrive, Teams	None (desktop apps only)
AI features	Copilot add-on available ($30/user/month)	No AI or Copilot features
Security	Defender, Purview, Conditional Access, DLP	No enterprise security features
Support lifecycle	Ongoing (tied to subscription)	End of support: October 2026
Enterprise pricing	E3: $36/user/month · E5: $57/user/month	~$440/user one-time (LTSC 2021)

Key facts

• Office 2021 reaches end of mainstream support in October 2026. After that, security patches only through 2026.
• Microsoft 365 includes cloud services — Exchange Online, SharePoint, OneDrive, and Teams — that Office 2021 does not.
• Microsoft 365 Copilot ($30/user/month add-on) requires a Microsoft 365 base license. Copilot does not work with Office 2021.
• For enterprises planning AI deployment, Microsoft 365 E3 or E5 is the only viable path.

Microsoft 365 enterprise plans

• Microsoft 365 Apps for Enterprise ($12/user/month) — Office apps only, no Exchange or Teams included.
• Microsoft 365 E3 ($36/user/month) — full suite: apps, Exchange Online, SharePoint, Teams, Intune, basic compliance.
• Microsoft 365 E5 ($57/user/month) — adds Defender for Endpoint P2, Purview Insider Risk, advanced compliance, Power BI Pro.

When Office 2021 still makes sense

Office 2021 (LTSC) fits a narrow set of scenarios.

• Disconnected or air-gapped environments that cannot use cloud services.
• Regulated systems where software version control is mandatory and continuous updates are not permitted.
• Specialized devices (kiosks, factory floor terminals) where desktop apps are needed with no cloud connectivity.

For most enterprise users, these scenarios do not apply. If your users need email, Teams, or AI features — choose Microsoft 365.

Migrating from Office 2021 to Microsoft 365

The migration has four steps. EPC Group runs each step with minimal user disruption.

1. Provision Microsoft 365 licenses for all users.
2. Deploy Microsoft 365 Apps for Enterprise via Intune or Configuration Manager.
3. Migrate email to Exchange Online (if not already there).
4. Configure OneDrive for Business file synchronization and redirect My Documents.

Timeline: small organizations (under 500 users) typically migrate in 4–8 weeks. Enterprise migrations take 8–16 weeks with phased rollout.

Impact on security and compliance

Microsoft 365 is not just a productivity upgrade. For enterprises, it changes your security and compliance posture significantly.

• Exchange Online adds anti-phishing, Safe Attachments, and Safe Links — not available in on-premises Exchange or Office 2021.
• Microsoft Purview DLP, sensitivity labels, and eDiscovery require Microsoft 365 licensing.
• Conditional Access policies in Entra ID require Microsoft 365 apps on Current Channel — not Office 2021.
• HIPAA, SOC 2, FedRAMP, and CMMC compliance frameworks all assume Microsoft 365, not Office 2021.

Frequently asked questions

What is the main difference between Microsoft 365 and Office 2021?

Microsoft 365 is a subscription with continuously updated apps plus cloud services (Exchange Online, SharePoint, OneDrive, Teams). Office 2021 is a one-time purchase of desktop apps with no cloud services and no feature updates after release. Office 2021 reaches end of support in October 2026.

Can I use Microsoft Copilot with Office 2021?

No. Copilot for Microsoft 365 requires an active Microsoft 365 subscription (E3, E5, Business Standard, or Business Premium) plus the $30/user/month Copilot add-on. Office 2021 does not qualify and has no AI features.

Is Microsoft 365 more expensive than Office 2021?

Microsoft 365 E3 is $36/user/month ($432/year). Office 2021 LTSC is approximately $440 per device one-time. Over three years, M365 E3 costs ~$1,296 per user — but includes cloud services, security, and continuous updates that Office 2021 does not provide.

What happens when Office 2021 reaches end of support?

Office 2021 mainstream support ends October 2026. After that, Microsoft provides security patches only through the extended support date. No new features will be added. Organizations still on Office 2021 after 2026 face increasing security risk as vulnerabilities are discovered but not fully patched.

How long does migrating from Office 2021 to Microsoft 365 take?

Four to eight weeks for most organizations under 500 users. Enterprise migrations (1,000+ users) with email migration, SharePoint setup, and phased rollout take 8–16 weeks. EPC Group uses Intune or Configuration Manager to deploy Microsoft 365 Apps for Enterprise at scale.

Upgrade to Microsoft 365

EPC Group manages Microsoft 365 migrations for enterprises of all sizes. Call (888) 381-9725 or schedule a discovery call to plan your migration.