Short answer
Microsoft 365 migration cost depends mainly on user count, data volume, source platform, identity complexity, device work and how many cutover waves you need. Small, simple moves cost far less than multi-tenant consolidations. Licences and migration tooling are separate line items. The reliable way to get a number is discovery followed by a fixed-price proposal for a defined scope.
Key facts
- The biggest cost drivers are scope and complexity, not user count alone.
- Licences, migration tool licences and professional services are separate costs.
- Fixed-price quotes after discovery reduce the risk of change orders.
- Device re-enrollment and identity work often cost more than mail moves.
- Weekend or after-hours cutovers and many waves add effort.
The main cost drivers
Two organizations with the same user count can have very different costs. The work is driven by what has to move and how much has to change around it.
- Source platform: Exchange Server, Google Workspace, another Microsoft 365 tenant, or file servers and cloud storage
- Data volume: mailbox sizes, archives, OneDrive, SharePoint and file share terabytes
- Identity: Entra Connect sync, UPN changes, MFA and Conditional Access redesign
- Devices: Intune enrollment, Autopilot, or re-enrolling devices into a new tenant
- Mail flow: domains, MX and Autodiscover changes, apps and devices that relay mail
- Waves and timing: number of cutover events and after-hours work
- Governance: rebuilding SharePoint structure and permissions rather than copying as-is
Cost components to budget for
A full budget usually has three or four parts. Keep them separate so you can compare quotes.
| Component | What it covers | Notes |
|---|---|---|
| Microsoft licences | Microsoft 365 plans and add-ons | Bought from Microsoft or a reseller; priced separately |
| Migration tooling | Third-party tool licences, if used | Native tools such as Cross-tenant mailbox migration may need their own licence |
| Professional services | Discovery, planning, migration, cutover, support | Usually the largest variable |
| Internal time | IT staff, testing, user champions | Often underestimated |
Engagement models
Fixed price for a defined scope gives budget certainty. It works when discovery has been done and assumptions are written down. Time and materials is flexible but shifts the risk of overruns to you. Some firms use a hybrid: a fixed-price discovery, then a fixed-price delivery.
Managed or retained support after migration is usually a separate monthly agreement. Ask whether hypercare after cutover is included in the project price.
Hidden costs to watch for
Most budget overruns come from items nobody inventoried.
- Scanners, printers and line-of-business apps that send mail through an on-premises server
- Large PST files or archives that need separate handling
- Shared mailboxes, resource calendars and distribution lists left out of scope
- Profile and Outlook reconfiguration on every device
- Running two systems in parallel longer than planned
How to get an accurate number
Provide a summary of your environment, allow a discovery period, and ask for a written proposal with scope, assumptions, exclusions and a fixed price. Compare proposals on the same scope. A low number with vague scope often ends up higher once change orders arrive.
If you need a figure early for budgeting, ask for a range and the assumptions behind it, then confirm after discovery.
Ways to lower the cost without adding risk
The cheapest data to migrate is data you do not move. Archive or delete stale mailboxes, departed-user OneDrives and old file shares before migration starts. Agree on retention rules first so cleanup decisions are not made under deadline pressure.
Reduce the number of decisions the project waits on. Settle domain names, UPN format, SharePoint site structure and who owns approvals before kickoff. Each week a migration team waits on an answer is a week of cost.
Use fewer, well-planned waves where your business allows it, and let internal IT handle tasks they already know well, such as user communication or desk-side Outlook checks, with the consultant owning the technical runbook. Ask each bidder which tasks you could take on to reduce the price, and what the trade-off would be.
How Accred Consulting approaches it
Accred Consulting does not publish rates because each environment differs. Engagements start with Discovery to inventory mailboxes, data, identity, devices and mail flow. The Proposal that follows sets clear scope, a fixed price and a timeline, so clients know the cost before work starts. Delivery runs with structured check-ins, then Handover with documentation and knowledge transfer, and optional Support retainers afterward. Clients work directly with US-based specialists, with no offshore handoffs, drawing on 400+ client projects and 150,000+ users migrated.
Track record: 400+ client projects, 2,000+ migration workstreams and 150,000+ users migrated by a US-based team. Company facts · Case studies
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