Migration
Gmail to Office 365 migration
Moving Gmail into Office 365 costs £95 or $125 per mailbox and takes three to four weeks for 50 users. The technical work is not the message copy but the label-to-folder mapping: Gmail stores one message under many labels, Exchange stores one message in exactly one folder.
| Fixed price | £95 / $125 per mailbox |
|---|---|
| 50 mailboxes | 3–4 weeks, one weekend cutover |
| Label handling | Primary label becomes the folder; others become categories |
| Size inflation | Expect 20–45% growth versus the Gmail figure |
| Delegation | Rebuilt as Exchange full-access and send-as |
| Kept in place | Filters translated to inbox rules where equivalents exist |
Labels are the whole problem
Gmail is a single store with views over it. A message tagged Clients, Invoices and 2025 exists once and appears in three places. Exchange Online has no such model: a message lives in one folder. Every migration tool resolves this by picking a primary label as the destination folder, and everything else is either duplicated or discarded.
We decide that mapping with you in discovery rather than accepting a tool default. Usually the rule is that project labels become folders, status labels become Outlook categories, and system labels are dropped. Once the rule is agreed the copy itself is uneventful.
- One primary label per message becomes the Exchange folder
- Secondary labels are written as categories, searchable in Outlook
- Nested labels become a folder hierarchy, not slash-separated names
- Starred and Important are mapped to flags rather than folders
Storage is bigger than the console says
Quote the Gmail storage figure to a licensing team and you will under-buy. Multi-labelled mail duplicates on write, attachments that Gmail deduplicated across a thread are re-expanded, and archive mail that lived in All Mail becomes a real folder with real bytes. Twenty to forty-five per cent growth is normal.
That matters because Exchange Online mailboxes have a hard ceiling per plan. We size against the post-migration figure, not the pre-migration one, and tell you before purchase if archive licensing is required.
Delegation, aliases and shared mail
Gmail delegation, Google Groups used as shared inboxes and send-as addresses have Exchange equivalents, but none of them migrate automatically. They are rebuilt from an audited inventory: who has access to what, which addresses can be sent from, and which groups are actually shared mailboxes in disguise.
This is where estates surprise their own administrators. A finance address delegated to three people, a support group forwarding to a personal account, an alias nobody remembers creating. We produce the list in discovery so the decisions are made before cutover rather than reported afterwards.
What the cutover weekend involves
Authentication is published first while Gmail is still live, then mail is pre-synced in full, then the MX record moves. Because everything is already copied, the weekend is a DNS change, a queue drain and a delta pass rather than a data transfer. Outlook profiles are created on Monday, and the two follow-up delta syncs at day 7 and day 14 catch stragglers.
Mobile devices are the most common Monday issue. Anyone using the Gmail app has to move to Outlook or reprofile native mail, which is a communications task more than a technical one, and we supply the user-facing instructions with the runbook.
What we see that others don't say
A Gmail mailbox that reports 14GB in the console frequently writes 20GB or more into Exchange Online, because every message carrying three labels is materialised as three separate copies in a folder-based store.
What this doesn't cover
- Gmail filters do not have one-to-one Outlook equivalents; complex filters are translated where possible and listed where not.
- Google Chat history has no supported path into Teams and is exported rather than migrated.
- Shared drives are handled as a separate file migration, not as part of the mailbox price.
- We do not rewrite line-of-business integrations built against the Gmail API.
Get a fixed price for this
Send your seat count, current platform and deadline. You get a fixed price and an available cutover date, usually within one working day, from the engineer who would run the work.
Prefer to talk? Call +44 20 7183 3436 (Mon–Fri 08:00–18:00 GMT), or message WhatsApp +44 7403 423563.
Questions we get asked
- How much does Gmail to Office 365 migration cost?
- £95 or $125 per mailbox as a fixed price, so 50 users is £4,750 or $6,250 including discovery, both delta syncs and thirty days of post-cutover support.
- What happens to Gmail labels in Outlook?
- The agreed primary label becomes the Exchange folder and remaining labels are written as Outlook categories, so the message is still findable by every tag it carried.
- Will mailbox sizes change after migration?
- Yes, upward. Multi-labelled mail duplicates when written into a folder-based store, so budget for 20 to 45 per cent more storage than the Gmail console reports.
How this page is verified
Reviewed by Workspace Migration Services migrations desk, Google Workspace migration engineers. Last checked .
- Per-mailbox pricing reflects the Workspace Migration Services rate card as of 2026-08-12.
- Label and folder behaviour follows Google's documented Gmail storage model as of 2026-08-12.
Sources you can check
Cite this page
Free to reuse with attribution. Copy whichever form your publication needs.
Plain citation
Workspace Migration Services, "Gmail to Office 365 migration", https://workspacemigration.services/migration/gmail-to-office-365 (last checked 2026-08-12).HTML with source link
<p>Gmail mailboxes typically grow 20 to 45 per cent when migrated to Exchange Online, because multi-labelled messages duplicate in a folder-based store. Source: <a href="https://workspacemigration.services/migration/gmail-to-office-365">Gmail to Office 365 migration</a> — Workspace Migration Services.</p>Embed this table
<table>
<caption>Gmail to Office 365 migration — Workspace Migration Services, 2026-08-12</caption>
<tr><th>Fixed price</th><td>£95 / $125 per mailbox</td></tr>
<tr><th>50 mailboxes</th><td>3–4 weeks, one weekend cutover</td></tr>
<tr><th>Label handling</th><td>Primary label becomes the folder; others become categories</td></tr>
<tr><th>Size inflation</th><td>Expect 20–45% growth versus the Gmail figure</td></tr>
<tr><th>Delegation</th><td>Rebuilt as Exchange full-access and send-as</td></tr>
<tr><th>Kept in place</th><td>Filters translated to inbox rules where equivalents exist</td></tr>
</table>
<p><a href="https://workspacemigration.services/migration/gmail-to-office-365">Gmail to Office 365 migration</a> — data maintained by Workspace Migration Services.</p>Related pages
Know your mailbox count?
Send the number of Gmail users and your target date. You get the label mapping rule, a fixed price and a cutover weekend, usually within one working day.