Check the tablespace usage in percentage and free space available in Oracle tablespaces

SELECT
    d.tablespace_name,
    ROUND(d.current_mb/1024,2) AS current_gb,
    ROUND((d.current_mb - NVL(f.free_mb,0))/1024,2) AS used_gb,
    ROUND(NVL(f.free_mb,0)/1024,2) AS free_gb,
    ROUND(d.max_mb/1024,2) AS max_gb,
    ROUND((d.max_mb - d.current_mb)/1024,2) AS autoextend_left_gb,
    ROUND((NVL(f.free_mb,0) + (d.max_mb - d.current_mb))/1024,2) AS total_free_left_gb,
    ROUND(((d.current_mb - NVL(f.free_mb,0)) / d.max_mb) * 100,2) AS pct_used_of_max
FROM
(
    SELECT
        tablespace_name,
        SUM(bytes)/1024/1024 current_mb,
        SUM(DECODE(autoextensible,'YES',maxbytes,bytes))/1024/1024 max_mb
    FROM dba_data_files
    GROUP BY tablespace_name
) d
LEFT JOIN
(
    SELECT
        tablespace_name,
        SUM(bytes)/1024/1024 free_mb
    FROM dba_free_space
    GROUP BY tablespace_name
) f
ON d.tablespace_name = f.tablespace_name;



TABLESPACE_NAME                CURRENT_GB    USED_GB    FREE_GB     MAX_GB AUTOEXTEND_LEFT_GB TOTAL_FREE_LEFT_GB PCT_USED_OF_MAX
------------------------------ ---------- ---------- ---------- ---------- ------------------ ------------------ ---------------
SYSTEM                               1.83       1.83          0         32              30.17              30.17                    5.71