As organizations embrace the full suite of Office 365 and intend to use Veeam Backup for Microsoft Office 365, I often get the question on how to properly size the storage for the repository for Office 365 backups.

There are, actually, three good ways to make a guesstimate on the required disk space to store the repository, whether it's on disk or in object storage:

1. Veeam Backup for Microsoft Office 365 Capacity Calculator
2. Use the latest Veeam Backup for Office 365 Calculator Excel sheet
3. Use the Measure-VBOOrganizationFullBackupSize PowerShell cmdlet

Veeam Backup for Microsoft Office 365 Capacity Calculator

On the Veeam website, there is an online capacity calculator website for Veeam Backup for Office 365. The online capacity calculator allows you to sign in with admin credentials of a Microsoft 365 tenant, but you can also manually enter values.

You can clearly distinguish the efficiency of object storage in the online capacity calculator when comparing to a disk repository. As a bonus, the online capacity calculator will even provide you with pricing information for object storage in Microsoft Azure.

The online capacity calculator was originally the work of Veeam’s Senior Solution Architect Hal Yaman, but has since seen a lot of improvements.

Use the latest Veeam Backup for Office 365 Calculator Excel sheet

The German Backup Bros Benedikt Däumling and Christian Stein have created a Veeam Backup for Microsoft Office 365 Calculator. It comes in the form of a Microsoft Excel file.

The Input Sheet allows you to enter specifics for the organization. On its Summary tab, you can easily switch between local and cloud, and get estimates on the required hardware and (cloud) storage.

Note:
This document is not an official Veeam document.

Note:
This document does not offer sizing for Microsoft Teams (yet).

Use the Measure-VBOOrganizationFullBackupSize PowerShell cmdlet

The Measure-VBOOrganizationFullBackupSize PowerShell cmdlet can be used to get the details on a size of a backed-up organization in Veeam Backup for Office 365.

You can use this details to find out how much space the backup of an organization will occupy on a backup repository.

Note:
In Veeam Backup for Microsoft Office 365 5.0, this PowerShell cmdlet is obsolete. It still works in Veeam Backup for Microsoft Office 365 5.0, but may not be supported in the next versions of Veeam Backup for Microsoft Office 365.

Note:
You cannot use this PowerShell cmdlet for organizations added using Azure AD applications and organizations for which backup of Microsoft Teams data is enabled.

In a Veeam Backup for Office 365 installation with a single organization, you can use this PowerShell cmdlet like this:

$org = (Get-VBOOrganization).Name

Measure-VBOOrganizationFullBackupSize -Organization $org