To check the current size of your data room, go to the Documents section, click "Export" and select "Project index".
This way, you will get the Project Index report downloaded to your local PC in an excel file.
Apart from the size of each document and the current overall size of the data room, the Project index report shows the number of pages, the submission date of each document, as well as its path inside the data room.
Note: Project index reflects just the current structure and size of a data room. To see how much data has been uploaded to the project overall (including data that has been removed from the recycle bin), please check the Data storage usage report in the Reports section.