Tool
Migration method picker
Six questions in, and out comes the migration tool that actually applies to your source and destination, the pre-sync window it needs, whether the estate should be phased, and an indicative fixed price at £95 or $125 per mailbox. Choosing the wrong tool is the most expensive decision in a migration, and it is usually made before anyone has looked at the limits.
| Recommended method | Google Workspace Migrate (GWM), with Data Migration Service for small estates |
|---|---|
| Why | GWM handles mail, Drive and permissions at scale; DMS is mail-only and fine below roughly 100 mailboxes. |
| Data in scope | 1,624 GB |
| Pre-sync window | 26 days before cutover |
| Realistic elapsed duration | 7 weeks, one weekend cutover |
| Sequencing | Single cutover weekend for the whole estate |
| Indicative fixed price | £4,750 / $6,250 (£95 / $125 per mailbox) |
| Against your deadline | Comfortable: 1 weeks of slack |
Planning figures only, excluding VAT or sales tax. Nothing you type here leaves your browser.
The recommendation follows the documented capability of each vendor tool rather than a preference. Google's Data Migration Service is mail-only, so an IMAP source needs a separate calendar and contact export whatever else you do. Google Workspace Migrate handles Drive and permissions but wants a Windows host and a real discovery phase. Microsoft's cutover migration stops being sensible somewhere around 150 mailboxes, and cross-tenant moves need an identity-collision plan before a single account is created.
Every schedule assumes authentication is published first, mail is pre-synced while the old platform stays authoritative, and the MX record moves last. That ordering is what turns a cutover into a DNS change rather than a data transfer.
What this doesn't cover
- Outputs are planning figures, not a quote, and exclude VAT or sales tax.
- Throughput assumptions come from our own project records; a throttled source host can be slower.
- The picker does not connect to your tenant, so it cannot read real mailbox sizes.
- Archive licensing, litigation holds and bespoke integrations are scoped separately.
Questions we get asked
- Which migration tool should I use to move to Google Workspace?
- Google Workspace Migrate for estates with shared file data or above roughly 100 mailboxes; the Data Migration Service for mail-only moves below that. From IMAP sources only the Data Migration Service applies, and it does not carry calendars or contacts.
- How do I know whether to phase a migration?
- Above roughly 150 mailboxes, phase by department with coexistence between waves. Below that a single cutover weekend keeps the project shorter and the runbook simpler.
- Does the picker send my details anywhere?
- No. It runs entirely in your browser, with no sign-up and nothing stored.
Related pages
Want the plan rather than the estimate?
Send your current platform, mailbox count and deadline. You get the migration method, a written runbook outline and a fixed price, usually within one working day.