Prior to Oracle 12c :
• VARCHAR2 : 4000 bytes
• NVARCHAR2 : 4000 bytes
• RAW : 2000 bytes
Extended Data Types in Oracle 12c optionally increases these maximum sizes.
• VARCHAR2 : 32767 bytes
• NVARCHAR2 : 32767 bytes
• RAW : 32767 bytes
Extended data types functionality is controlled using the MAX_STRING_SIZE initialization parameter. Default value is 'STANDARD' which sets the maximum sizes to traditional lengths. Setting it to 'EXTENDED' allows it to extended it to 32767.