Size of Oracle database

If you want to know the size of an Oracle database (physical size and real size occupied by all database objects) use the following selects:

-- Physical size of database
select chr(10)||'Total Physical Size of Database : '|| round(sum(bytes/(1024*1024*1024)),2)||' GB'
from dba_data_files;

-- Total size occupied by objects
select 'Total Space Occupied By Objects : '|| round(sum(bytes/(1024*1024*1024)),2)||' GB'||chr(10) from
dba_segments;