Query to find out Required space while import/impdp

set linesize 300
SELECT  dts.tablespace_name,
NVL(ddf.bytes / 1024 / 1024, 0) avail,
NVL(ddf.bytes - NVL(dfs.bytes, 0), 0)/1024/1024 used,
NVL(dfs.bytes / 1024 / 1024, 0) free,
TO_CHAR(NVL((ddf.bytes - NVL(dfs.bytes, 0)) / ddf.bytes * 100, 0), '990.00')
"Used %" ,
TO_CHAR(NVL((ddf.bytes - NVL(ddf.bytes - NVL(dfs.bytes, 0), 0)) / ddf.bytes
* 100, 0), '990.00') free_pct,
decode(sign(
(NVL(ddf.bytes - NVL(dfs.bytes, 0), 0)/1024/1024)/0.85 - NVL(ddf.bytes / 1024 /
1024, 0)),-1,0,(NVL(ddf.bytes - NVL(dfs.bytes, 0), 0)/1024/1024)/0.85 - NVL(ddf.
bytes / 1024 / 1024, 0))  "Required MB"
FROM
sys.dba_tablespaces dts,
(select tablespace_name, sum(bytes) bytes
from dba_data_files group by tablespace_name) ddf,
(select tablespace_name, sum(bytes) bytes
from dba_free_space group by tablespace_name) dfs
WHERE
dts.tablespace_name = ddf.tablespace_name(+)
AND dts.tablespace_name = dfs.tablespace_name(+);