Important note!
Most of the storage space is in Google Photos and Google Drive, so it is important before and after transferring the files to a private Gmail account to check whether the volume in both has dropped below 25 gigabytes.
In addition, changes made in the storage volume are not immediately visible and therefore should be checked only after 24 hours.
Click on the email icon on the top right or left (depending on the language) and then click on Manage your google account
Click on Payments and Subscriptions
In the Account storage tab you can see how much storage you're using
You can see additional information by clicking Manage storage