​​​How long does a migration take?


It can be difficult to accurately predict how long a migration will take. Several factors that will have an impact on timing are system load, bandwidth, average item size, and source or destination bottlenecks.​

MigrationWiz is unlikely be the bottleneck, as we are connected to the largest migration farms and we do not throttle data. However, this is a variable process with many moving parts.

Here is a very rough breakdown of what can be expected. Note: This is not an SLA; it is an example based on a very large sample of migration speeds experienced by our Partners.

  • Low end: 250mb per hr/per user
  • Mid end: 750mb per hr/per user
  • High end: 1.25gb per hr/per user

Here are some factors that will affect migration speeds:

 Network Speed:

How fast are the Source and Destination servers connected to the internet? The entire process is only as fast as the slowest link. We've connected to networks that range from a T1 to networks that host multiple gigabit connections, but depending on the data center that the migration server is located in, we will most likely be connected with a gigabit or 10-gigabit connection.

Server Load:

What type of equipment is the Source and Destination mailbox deployed on? Our migration process is not usually noticeable if the server is sized appropriately for your organization.


Does the Source or Destination system throttle the amount of data that can be read or written? Several systems implement throttling policies that prevent full utilization of available network bandwidth.

Number of ​Folders:

Depending on the number of folders and the Source system, enumeration of the folders might slow down the migration process. Read more on this topic in How does folder size impact migration speeds?

Network Latency:

The network latency is dependent on the quality of the connection between our data center and the Source and Destination. We utilize the fastest internet backbones available globally. Because of our global migration farm, our connections are made from networks with low latencies.

Mailbox Migrations

Simultaneous Mailbox Migrations:

MigrationWiz is able to migrate hundreds of thousands of mailboxes simultaneously. Migrating more mailboxes at the same time allows parallel processing, reducing the duration of your migration. If all of your mailboxes are migrated at the same time, the migration duration is the time it takes to migrate the largest mailbox.

Number of Mailbox Items & Mailbox Size:

There is a per-item transaction overhead and time cost. For example, given two mailboxes of the same size but with a different number of items, the one with fewer items will migrate faster than the one with more items.

The more data there is, the longer the migration. When migrating between two hosted providers, the size of the mailbox is unlikely to overload our bandwidth, but some Destinations might have capacity issues. When mailboxes exceed a certain size, speed reduction may occur because of those scalability issues. 

Mailbox Errors:

Errors can occur for a number of reasons: corrupt items, network outages, etc. MigrationWiz contains automated, self-​corrective technology that deals with errors automatically in most cases. For those it does not automatically handle, our Help Center offers resources and guidance. 


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