Google Workspace to Microsoft 365: a practical migration guide

Most Google Workspace → Microsoft 365 migrations we see start with a business decision, not an IT one. The most common triggers:

• A line-of-business application that only works with Microsoft (Dynamics 365, industry software, a client’s compliance requirement).
• An acquisition that puts you on M365 or forces standardization.
• A new team member who wants Excel, Teams, or SharePoint the way “real” businesses use them.
• The realization that you’re already paying for Microsoft licensing via Windows or Office and Google Workspace is a redundant expense.

Whatever the trigger, here’s what an actual migration looks like end-to-end.

Cost expectations

Licensing: Microsoft 365 Business Standard is $12.50/user/month; Business Premium (adds Intune device management and better security) is $22/user/month. For a 25-person business, expect $310–$550/month in Microsoft licensing.

Migration project (one-time): typically $2,500–$8,000 for under 50 users, depending on complexity. A “clean” migration (Google Workspace mailboxes, Drive files, calendars, no legacy apps) sits at the lower end. A migration with legacy on-prem Exchange remnants, thousands of shared drives, or custom Google Apps Scripts sits higher.

Watch out for: vendors who quote “per mailbox” without a discovery call. Every migration has surprises; a vendor who’s committed to a price before seeing your environment is either padding for surprises or planning to nickel-and-dime you when they show up.

Timeline

For a typical 25–75 user business:

Weeks 1–2: Discovery and planning

• Full inventory: users, mailboxes, shared drives, groups, aliases, third-party integrations.
• Decide what moves as-is, what gets restructured, what dies.
• Choose licensing SKUs (Business Standard vs. Premium vs. Enterprise) — often you can downgrade some users to save money.

Week 3: Tenant setup and preparation

• Provision the M365 tenant, verify domain ownership, set up conditional access baselines.
• Configure identity — either sync from an existing directory or create fresh users.
• Deploy backup (Microsoft only retains deleted items 30–93 days; you need third-party retention).

Week 4: Pilot cutover

• Migrate a test group of 3–5 users (typically IT + one leader + one power user).
• Validate mail flow, calendar sharing, file access, mobile devices, third-party integrations.
• Fix anything unexpected before the main event.

Week 5–6: Full cutover

• Freeze Google Workspace changes on Friday evening.
• Run final delta sync of mailboxes, calendars, and Drive over the weekend.
• Cutover DNS Monday morning; users log into M365 with clear communication.

Days 1–5 post-cutover: on-site or remote hands to catch every “why doesn’t my printer work?” and “where’s my old email?” question in real time.

The gotchas nobody tells you

Google Drive sharing doesn’t map cleanly to SharePoint. Google’s “share with anyone with the link” and infinite nested folder permissions don’t translate to SharePoint’s site/library/folder model. Plan for a restructure, not a copy — often the migration is the moment to fix drive sprawl that’s been years in the making.

Calendars break in weird ways. Recurring meetings sometimes lose exceptions. Room resources need to be recreated. External meeting invites created before cutover may or may not update the room correctly. Warn users; nothing catastrophic, but plan for a few “hey where did that meeting go?” tickets.

Google Groups vs. Microsoft 365 Groups vs. distribution lists vs. security groups. Google collapses these; Microsoft doesn’t. A migration is when you decide which use case each old Google Group needs to become, and it’s rarely a 1:1 map.

Third-party integrations. Anything that uses OAuth into Google Workspace (Slack, Zoom, industry-specific apps, single sign-on) needs to be reconfigured to trust Microsoft Entra ID instead. Inventory these early — the last surprise you want at cutover is realizing your accounting app can’t authenticate.

Mobile device email. Users need to remove the old Google account from their phones and add the new M365 account. If you’re rolling out Intune at the same time (recommended), this is the moment to enroll devices.

What we recommend against

Don’t try to migrate yourself. Even if you have a technical person on staff. The tools (BitTitan MigrationWiz, Quest, native Google/Microsoft utilities) look approachable but fail in edge cases that are expensive to hit in production. Pay for the project; do it once.

Don’t split the cutover across departments over weeks. It’s tempting — “let’s do sales first, then engineering next month.” What happens is you run both platforms in parallel for months, coexistence issues eat you alive, and you end up paying for both licenses simultaneously.

Don’t do this the same week as another major change. No office move, no new phone system, no accounting system rollover. One thing at a time.

When to not migrate

• You’re a Google-native workflow shop (Google Docs is the atomic unit of your work). M365’s collaborative editing is close but not identical. If Docs is a religion at your company, migrating will annoy people.
• Your team is 100% remote and lightweight. M365’s advantages (Intune, SharePoint governance, Teams) mostly help hybrid/office businesses.
• You have < 10 users and no compliance drivers. The licensing savings don’t justify the project cost.

For everyone else, M365 usually wins on total cost and capability over a 3-year horizon.

If you’re weighing a migration and want a specific plan for your environment, we do fixed-fee discovery calls that produce a scoped proposal you can shop around. Book here.