Office 365 Backup Analysis

analysisAre you wondering how much local storage your MS Office 365 backup requires? Are you wanting to learn more about your user’s behaviour while connected to your services over time to better manage your MS Office 365 licensing costs? Do you have your management team wanting more insight 

into your organisation’s license usage? 


Hi All, thanks for your support with providing feedback, testing, and using my Office 365 Analysis, please note that this calculator become Veeam Software official, and you still can access and enjoy the new, modified tool on the following URL: Veeam Backup for O365 Capacity Calculator



All these questions and more can be solved using a community WebApp tool. Let’s discuss that option on this blog post. 

After two months or so of hard work with endless design ideas, mistakes, and frustration, I am pleased to release to the community, MS Office 365 Backup Analysis Tool – Version 2. 

If you are one of my blog followers, you are already familiar with the VBO Sizing Tool v1 that released last year. With VBO Sizing Tool v1, any organisation can query the size of their MS Office 356 mailbox databases to get an estimate of the data size the MS Office 365 Exchange Online Backup is going to send to local storage. 

With MS Office 365 Backup Sizing Tool – Version 2, I have added more functionality to the WebApp tool. With this new functionality, the MS Office 365 system administrator can: 

  • Easily retrieve the total size of the storage used by Mailboxes, SharePoint, and OneDrive.
  • Retrieving the total number of MS Office 365 provisioned users across the organisation, and the total number of licenses assigned per service; i.e. Exchange, SharePoint and OneDrive.
  • The usage trends of active and inactive users for the last month, per service; i.e. Exchange, SharePoint and OneDrive.
  • Calculating the required total local storage size of the Exchange, SharePoint and OneDrive backups.
  • Calculation the required size of the backup infrastructure.
  • Backup environment and storage size projection for future growth  

All those functionalities and more are delivered through a .Net WebApp hosted on Azure; you are welcome to use it for free by browsing to the following URL: Veeam Backup for O365 Capacity Calculator There, you are greeted with this screen: 

Screen Shot 2019-10-23 at 3.20.08 pm

Login Process and Requirements

Let’s start with this statement; it is not necessary that you log in as a Global Administrator on your MS Office 365 installation to use this WebApp. Having said that, using a Global Admin login will make your login process and report retrieval so much easier. If you choose not to use a Global Administrator login, then no worries, the WebApp login process is smart enough to allow you to log in after you use a Global Admin login to approve your administration consent to another login. You need this for your Graph API report retrieval. 

I recommend creating an MS Office 365 user, and then assign the Application Administrator roles to it in your Azure Active Directory. See the following screenshot:

Screen Shot 2019-10-23 at 3.59.15 pm

After the user is created and configured, you can use this username to login to the WebApp and begin retrieving the reports. 

During the login process of your special user, the WebApp creates an Azure Active Directory Enterprise Application and assigns the following permissions: 

  • User Sign in 
  • Application: Reports.Read.All 

Screen Shot 2019-10-23 at 3.56.10 pm


After login, you are directed to the Dashboard web page. The Dashboard web page allows you to learn about your MS Office 365 organisation’s licensing consumption. It also shows users’ Active/Passive trends for the past 30 days, listed by service. Click on each service to see a 30 days trend of Active/Passive use: 

Screen Shot 2019-10-26 at 10.52.41 pm

Note: Microsoft Graph API reports are always two days behind.

Service Backup Sizing

Before you get started with backing up your MS Office 365 organization, you should examine your local storage. You are checking to see if you have enough space to store your MS Office 365 backup data for each service, or across the entire organisation’s services; i.e., Exchange, SharePoint and OneDrive 

To see the information for each service, click on one of the Services hyperlinks from the left side menu. After you have chosen the service you wish to view, you are redirected to that service’s webpage. See the following screenshot for the Mailbox Service, chosen as an example: 

Screen Shot 2019-10-23 at 4.17.36 pm

From this webpage, you can see the following information about your Mailbox Service: 

  • Total Storage Usage for the past 7, 30, 90 and 180 days.
  • Total Active/Inactive user for the past 7,30, 90 and 180 days.
  • Total number of Mailboxes.
  • Change rate for the reporting period i.e., 7, 30, 90 and 180 days.

Using the retrieved data, you can easily review the size of your local storage used for backup. If it needs modifying, you can do that by adjusting the retention policy setting. Check the screenshot above again, and you can see Retention at the lower left.

Backup Sizing Total Storage and Infrastructure

After you have checked the size of each service, you can browse to the Backup Sizing webpage; from here you can size the total backup storage needed for your backups. You can also review your backup infrastructure requirements, as shown in the following screenshot:

Screen Shot 2019-10-24 at 10.52.14 am

The backup sizing webpage also allows you to calculate your data space sizing for the future growth of your MS Office 365 storage consumption. From this webpage, you can also check on the user growth, by service, and use those figures in your calculations for your planning. 

Archive Mailbox

Unfortunately, there is no specific Graph API where you can query your organisation’s archive mailboxes usage and size. To overcome that issue on the Backup sizing webpage, I have provided you with a PowerShell script. The Admin can download that script and run it locally to retrieve the number of mailboxes with Archive enabled, and read out the total size of all the archive mailboxes 

After running the script, the Admin can manually enter the values under the archive mailbox sizing, as shown below: 

Screen Shot 2019-10-24 at 10.53.28 am

Note: You must enable this feature before you can use it. Click to tick the checkbox at the button right corner.


The MS Office 365 analysis WebApp tool is not only helping with MS Office 365 Backup sizing, but also provides the MS Office 365 Admin with some insight into the MS Office 365 organisation’s storage consumption, license usage, and other useful data about the way your users are consuming your services. All these reports can help the Admin to better manage the organisation’s subscription costs and more.

I’m extremely happy with this product release. During the development of this product, I learned a lot about Microsoft Graph and its APIs, in addition to learning the necessary coding, scripting, and product management and release cycles. I certainly put my Scrum Master certificate to the test.

The WebApp is developed for the community to use, and it is free of charge. To continue the development of this product, I am finalising version 3, where I am focusing on including more reporting and analytics for both MS Office 365 and MS Office 365 Backup.

I hope you will find this WebApp useful, and please help the community by sharing.

28 thoughts on “Office 365 Backup Analysis

  1. Hi Hal,
    Thanks for sharing your latest WebApp. I am logging in with our Global Admin account but am having issues connecting to our MSO365 tenant for Exchange and SharePoint (OneDrive works fine)
    “We are finding difficulty retrieve data from office 365. Detail : Value was either too large or too small for an Int32.”

    • Hi Aaron, Thanks for your feedback, I made some changes, can you please re-check and update me?, if you still experience the same issue, please ping me through LinkedIn, and we can have a session to investigate further.

      • Hi Hal,
        I have the same issue as Aaron. Can you please post the solution? Thanks!

      • Hi Thomas, there is no one solution for all unfortunately. If you wish to help and contribute to this community tool you can ping me on LinkedIn and we can have a session to debug your issue. Thanks for your understanding and hope to hear from you soon.

  2. Hi Hal. Great work on this front, it’s easy to manage the data. I am also havinvg the same as Aaron that my mailbox is having difficulty..

    • Hi Steve thanks for your feedback, I been able to reproduce the same error on my lab and got logs from other two customers which will allow me to work on a fix. Hopefully will come up with a fix in two days max

  3. Hi All , Version 2.0.3 was released and addressed all the issues reported. please give it a try and let me know if you still experiencing any issues

  4. Awesome work. Its working now and mailbox i can now see and backup sizing also showing good result. Thanks for this HalYaman. It makes it easier to navigate through the reports.

  5. Hi, i tried it today and got this Error Message after the Login with Admin Account: We are finding difficulty retrieve data from office 365.

    Detail : String was not recognized as a valid Boolean.

    • Hi Thomas, not on this version but this release but if you connect via Linkedin and let me know what feature you are looking for maybe I can plan to add on next release

  6. Might be a calc error here, one person account for testing pretty sure it is much less than t TB. One typo, Changes.
    Repository Breakdown
    MB GB
    Daily Change 1 0
    Chages on the retention period 1 0
    Working Area Size 191 0.19
    Database Size 1911 0.19

    • Hi Lou, and thanks for your feedback. The calculations will round any .xx to 1 and if the size is less the 1 GB, I will not convert to 0.xxxx GB – I decided so for better presentation

  7. Hi colleague, this is an awesome and very helpful tool, thanks a lot!
    Best greetings from the other side of the planet, Herbert

  8. Just found out, this is one of the rare tools, which become silently better. 🙂
    You have added a cost analysis!

    • Hi Damaris,

      With the current version, you can only export the summary report which includes the Azure costs and storage sizes.
      Can you please let me know what kind export info you wish to see on an export report (also format)? (working on the new version and depends on some factors maybe I will include such a report)


  9. Best tool that I found for VBO sizing. Love your work Office 365 Backup Analysis!!!


  10. Hi @bastiaan, unfortunately this tool no longer available under CloudOasis, Veeam purchased the rights for this Tool and I develop a new version with the help of veeam R&D and hosted under the following url , please enjoy the new version

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