How are egress charges calculated in Azure data centers?
When you migrate data that crosses between Azure Regions (that is, moves from one data center to another), you are subject to egress charges. However, if the data you migrate is from a Source to a Destination that are both within a single Azure Region (that is, does not cross from one data center to another), then you do not incur egress charges.
Azure egress charges apply only when data crosses from one Azure region to one or more other Azure regions. Any traffic that originates and terminates within a single Azure region is not subject to egress charges. It does not matter that traffic moves from one subscription to another. If the data remains within the same region, there are no egress charges.
For more information about egress charges, see Microsoft Azure: Data Transfers Pricing Details.
For more information about Azure Regions (and data center locations), see Microsoft Azure: Azure Regions (data centers).