Being non-DBA person, I always face this issue of checking the free space available in my production Database. If you are using ASM and wanted to check the same please us below command to get the required output:
SELECT df.tablespace_name TABLESPACE, df.total_space TOTAL_SPACE,
fs.free_space FREE_SPACE, df.total_space_mb TOTAL_SPACE_MB,
(df.total_space_mb - fs.free_space_mb) USED_SPACE_MB,
fs.free_space_mb FREE_SPACE_MB,
ROUND(100 * (fs.free_space / df.total_space),2) PCT_FREE
FROM (SELECT tablespace_name, SUM(bytes) TOTAL_SPACE,
ROUND(SUM(bytes) / 1048576) TOTAL_SPACE_MB
FROM dba_data_files
GROUP BY tablespace_name) df,
(SELECT tablespace_name, SUM(bytes) FREE_SPACE,
ROUND(SUM(bytes) / 1048576) FREE_SPACE_MB
FROM dba_free_space
GROUP BY tablespace_name) fs
WHERE df.tablespace_name = fs.tablespace_name(+)
ORDER BY fs.tablespace_name;
