User below query to find Database Size :
SELECT d.name AS [Database Name],
ROUND(SUM(mf.size) * 8 / 1024, 0) [Size (MB)]
FROM sys.master_files mf
INNER JOIN sys.databases d ON d.database_id = mf.database_id
WHERE d.database_id > 4
GROUP BY d.name
ORDER BY d.name
