Get size of all tables in database

SELECT
    T.NAME AS TABLENAME,
    S.NAME AS SCHEMANAME,
    P.ROWS AS ROWCOUNTS,
    SUM(A.TOTAL_PAGES) * 8 AS TOTALSPACEKB,
    CAST(ROUND(((SUM(A.TOTAL_PAGES) * 8) / 1024.00), 2) AS NUMERIC(36, 2)) AS TOTALSPACEMB,
    SUM(A.USED_PAGES) * 8 AS USEDSPACEKB,
    CAST(ROUND(((SUM(A.USED_PAGES) * 8) / 1024.00), 2) AS NUMERIC(36, 2)) AS USEDSPACEMB,
    (SUM(A.TOTAL_PAGES) - SUM(A.USED_PAGES)) * 8 AS UNUSEDSPACEKB,
    CAST(ROUND(((SUM(A.TOTAL_PAGES) - SUM(A.USED_PAGES)) * 8) / 1024.00, 2) AS NUMERIC(36, 2)) AS UNUSEDSPACEMB
FROM
    SYS.TABLES T
INNER JOIN     
    SYS.INDEXES I ON T.OBJECT_ID = I.OBJECT_ID
INNER JOIN
    SYS.PARTITIONS P ON I.OBJECT_ID = P.OBJECT_ID AND I.INDEX_ID = P.INDEX_ID
INNER JOIN
    SYS.ALLOCATION_UNITS A ON P.PARTITION_ID = A.CONTAINER_ID
LEFT OUTER JOIN
    SYS.SCHEMAS S ON T.SCHEMA_ID = S.SCHEMA_ID
WHERE
    T.NAME NOT LIKE 'DT%'
    AND T.IS_MS_SHIPPED = 0
    AND I.OBJECT_ID > 255
GROUP BY
    T.NAME, S.NAME, P.ROWS
ORDER BY
    T.NAME


https://stackoverflow.com/questions/7892334/get-size-of-all-tables-in-database