My stuff

The following queries can be used to find out how much space a table takes up. The first query gets the block size used in this database. The second one shows how many blocks are used for a table.

  SELECT VALUE
    FROM v$parameter
  WHERE name = 'db_block_size';
 
  SELECT blocks, last_analyzed
    FROM all_tables
  WHERE owner = 'X'
     AND TABLE_NAME = 'Y';

The blocks field will have a valid value if the table has been analyzed recently, that is why the last_analyzed field is selected as well.