The maximum storage size for a Microsoft SQL Server DB Instance is 4 TB for all instances except theSQL Server Express edition, which limits storage to a total of 300 GB. The minimum storage size for aMicrosoft SQL Server DB Instance is 20 GB for the Microsoft SQL Server Express and Web Editionsand 200 GB for the Standard and Enterprise Editions. http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/CHAP_SQLServer.html