Microsoft 365 migration cost is driven by four things: how many mailboxes move, how much data sits behind them, whether the old and new systems have to run side by side for a while (coexistence), and how much cleanup the old environment needs before anything is worth moving. The licenses themselves are published by Microsoft and are the easy part. The labor is the part that varies, and it varies a lot between a twelve-person firm on a hosted Exchange plan and a sixty-person firm with a Google Workspace tenant, a file server and fifteen years of PST archives. NetSys quotes migrations per business after looking at the source environment, and our agreements are month to month. Here is what moves the number.
What is usually included in a Microsoft 365 migration quote?
| Usually in the migration fee | Usually priced or billed separately |
|---|---|
| Discovery of mailboxes, groups, shared mailboxes and data volumes | Microsoft 365 licenses (billed by Microsoft or through a partner) |
| Tenant setup, domain verification and identity configuration | Third-party migration tool licenses, often priced per mailbox |
| Mailbox, calendar and contact migration | File server to SharePoint and OneDrive moves |
| DNS cutover and mail-flow testing | PST archive ingestion and public folder conversion |
| Outlook and mobile device reconfiguration | Security baseline: MFA, conditional access, Defender policies |
| A cutover window and post-migration support days | Backup of the new tenant, and user training |
The right column is where two quotes diverge. A migration quote that stops at mailboxes is accurate as far as it goes, and it leaves the file server, the archives and the security configuration for a second project that nobody has priced.
How do mailbox count and data volume change the price?
Mailbox count sets the base. Every mailbox needs to be created, licensed, migrated, verified and reconnected in Outlook and on the phone, so labor scales with the count, though not in a straight line: the fiftieth mailbox is quicker than the fifth because the process is running. Shared mailboxes, resource calendars, distribution groups and aliases count too, and they are the items most often missed in discovery. Ask a provider whether the quote counts every mailbox object or only the people.
Data volume sets the calendar and the tooling. Moving a few gigabytes per mailbox over an office internet connection is an evening. Moving hundreds of gigabytes per mailbox, or a multi-terabyte file server, means seeding data over days or weeks before the cutover, and Microsoft throttles migration throughput to protect the platform, which no provider can override. Large volumes also push a project toward third-party migration tools, which are usually priced per mailbox or per user, and onto a staged timeline rather than a single weekend.
Why does coexistence cost more than a cutover?
A cutover migration moves everyone at once: seed the data, switch DNS on a Friday evening, reconnect devices on Monday. It is the least expensive method and it suits small firms, because the disruption is short and there is only one system to support afterward.
Coexistence means the old and new systems run together, with mail flowing between them and calendars visible across both, while users move in batches. Exchange hybrid is Microsoft's version for on-premises Exchange servers. Coexistence is the right choice when the business cannot tolerate a single cutover weekend, when there are hundreds of mailboxes, or when a tenant-to-tenant move after an acquisition has to keep two companies working during the transition. It costs more because it requires configuring and testing the bridge between systems, supporting two environments for the duration, and running several cutover events instead of one.
Migrating from Google Workspace has its own shape. Microsoft provides a migration path inside the Exchange admin center for mail, calendar and contacts, and Migration Manager for Google Drive content, so the tooling cost is low. Google's sharing model does not map one to one onto SharePoint and OneDrive, though, and the labor of deciding where shared drives should live is where the hours go.
What cleanup should happen before the move, and who pays for it?
Every environment carries dead weight: mailboxes for people who left years ago, distribution lists nobody uses, PST files scattered across laptops, public folders that became a filing cabinet, and a file server with duplicate folder trees. Migrating all of it costs money twice: once to move it, and every month afterward in licenses and storage for content nobody opens.
Cleanup is worth doing before migration, and it is worth pricing as its own line. Deciding what to archive, what to delete and what to convert to a shared mailbox is a business decision that needs an owner inside your company, and the provider's job is to give you the inventory and the options. When a quote is unusually low, cleanup is often the item that was skipped, and the migration simply reproduces the mess on a new platform.
What costs show up after the migration?
- Licenses. The monthly per-user fee is published by Microsoft and continues for as long as you use the service. Choosing the right plan matters; our comparison of Business Premium and Business Standard explains what the security features in Premium replace.
- Backup. Microsoft keeps the service running; it does not keep an independent, restorable copy of your data on your behalf beyond its retention windows. A separate backup for mail, OneDrive, SharePoint and Teams is a real line item. See Microsoft 365 backup.
- Security configuration. A fresh tenant is not hardened by default. MFA, conditional access, anti-phishing policies and device compliance are their own project, described in our Microsoft 365 security checklist.
- Training and support. The first two weeks after a migration generate more help desk tickets than any other two weeks of the year. Ask whether post-migration support days are included.
How do you compare Microsoft 365 migration quotes?
- Object count. Users, shared mailboxes, resources, groups and aliases, listed, so both quotes cover the same tenant.
- Data volume and method. Total gigabytes, the migration tool, and whether the plan is cutover, staged or hybrid.
- Files and archives. Whether the file server, PSTs and public folders are in scope or deferred.
- Security baseline. Whether the tenant is configured to a written standard before users move in.
- Ownership. The tenant and the domain must be registered to you, with the provider as a delegated administrator.
- Support window. How many days of post-cutover support are included, and at what hours.
Frequently asked questions
How much does it cost to migrate to Microsoft 365?
The labor cost depends on mailbox count, data volume, the source platform, whether coexistence is required and how much cleanup the old environment needs, which is why NetSys quotes per business after a discovery pass. The license cost is separate and published by Microsoft per user per month. A small firm moving a few dozen mailboxes from hosted Exchange in a single cutover is the simplest case. Adding a file server, archives, Google Workspace or a hybrid period moves the project up in steps.
How long does a Microsoft 365 migration take?
Small cutover migrations are typically planned over a few weeks and executed over a weekend: discovery and tenant setup first, data seeding in the background, then the DNS switch and device reconnection. Coexistence projects run longer because users move in batches. Data volume and Microsoft's migration throttling set the floor on seeding time, so a provider promising a same-week move for a large tenant is guessing.
Can we migrate from Google Workspace to Microsoft 365 without downtime?
Mail can move with very little interruption: Microsoft's built-in Google Workspace migration copies mail, calendars and contacts while Google is still live, and the DNS switch happens once the copy is current. The visible disruption is on the user side, where people move from Gmail to Outlook and from Drive to OneDrive and SharePoint. Budget for training and a support window there, because that is where the tickets come from.
Does Microsoft help with migration for free?
Microsoft's FastTrack program offers remote migration assistance for tenants that meet its published eligibility rules, which include a minimum license count that many small businesses do not reach. Microsoft's own migration tools inside the Exchange admin center and Migration Manager are free to use for any tenant. What neither provides is the discovery, cleanup, security configuration and device work, which is where a provider earns its fee.
Getting a quote for your migration
A migration quote is only as good as the inventory behind it, so we start with a look at your current environment: mailboxes, data, files, archives and what needs to keep running during the move. Our Microsoft 365 migration page describes how we run the project, and Microsoft 365 management covers what happens afterward, month to month.
Sources and further reading
- Ways to migrate email to Microsoft 365, Microsoft's overview of cutover, staged and hybrid methods.
- Migration Manager for Google Workspace.
- Microsoft FastTrack, including its eligibility rules.
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