Do you want to monitor the storage capacity of your SharePoint Online Environment in an automated way? In this blog post, I will show you how to use Graph to read the storage capacity programmatically and avoid running out of storage space. Hey SharePoint Admin, have you also gazed at this storage chart in Active Sites section and scratched your head? Sure, it is good, but you cannot use it for automated monitoring.

There is confusion around how the storage is calculated in SharePoint Online. I believe, in SharePoint Online 1 TB is 1024 GB (based on powers of two), although the SI Prefix is for numbers based on powers of 10 (1TB = 1000GB, Wikipedia). In this post I would like to summarize the results of my investigations and I hope Microsoft or the community can confirm or disconfirm this. First, let me explain why we care about it.