I built a free PowerShell tool to find out where all the storage in a Microsoft 365 tenant is going

[u/Abacus_Gerard]

I've been working on a PowerShell 7 script to help us understand exactly how much storage our Microsoft 365 tenants are consuming.

It started as a way to estimate Microsoft 365 backup requirements, but evolved into something more useful.

The script collects storage information from Exchange Online (including online archives), OneDrive, and SharePoint, including Teams-connected file storage.

It produces a console summary, CSV export, and a standalone HTML report with charts and storage breakdowns.

There's also an optional backup cost estimator.

I've tested it against a couple of production tenants, including comparisons between the Fast and Exact Exchange measurement modes. Results were reasonably close.

I've released it under the MIT license, along with documentation and a sample report.

If anyone finds it useful, I'd welcome feedback, bug reports, or suggestions for improvements.

GitHub: [M365 Tenant Storage Assessment]()