Oracle Query to see Used and Free TableSpace Size

Dear friend,
Below query will reveal the "Used Space" and "Free Space" in all the Tablespaces present in your database:

SELECT DF.TABLESPACE_NAME "TABLESPACE",
      DF.BYTES / (1024 * 1024) "SIZE (MB)",
      SUM(FS.BYTES) / (1024 * 1024) "FREE (MB)",
      NVL(ROUND(SUM(FS.BYTES) * 100 / DF.BYTES),1) "% FREE",
      ROUND((DF.BYTES - SUM(FS.BYTES)) * 100 / DF.BYTES) "% USED"
 FROM DBA_FREE_SPACE FS,
      (SELECT TABLESPACE_NAME,SUM(BYTES) BYTES
         FROM DBA_DATA_FILES
        GROUP BY TABLESPACE_NAME) DF
WHERE FS.TABLESPACE_NAME (+)  = DF.TABLESPACE_NAME
GROUP BY DF.TABLESPACE_NAME,DF.BYTES;


To know the space used by a Table, Index or anything use below query:

SELECT SEGMENT_TYPE,BYTES/1024/1024 "SIZE IN MB" FROM DBA_SEGMENTS WHERE SEGMENT_NAME = 'INDEX_NAME_OF_TABLE';

SELECT SEGMENT_TYPE,BYTES/1024/1024 "SIZE IN MB" FROM DBA_SEGMENTS WHERE SEGMENT_NAME = 'TABLE_NAME';