How to Get Table Sizes of a Database in Microsoft SQL Server

-- Get sizes of multiple tables
use DATABASENAME
GO
IF OBJECT_ID('tempdb..#SpaceUsed') IS NOT NULL
	DROP TABLE #SpaceUsed

CREATE TABLE #SpaceUsed (
	 TableName sysname
	,NumRows BIGINT
	,ReservedSpace VARCHAR(50)
	,DataSpace VARCHAR(50)
	,IndexSize VARCHAR(50)
	,UnusedSpace VARCHAR(50)
	) 

DECLARE @str VARCHAR(500)
SET @str =  'exec sp_spaceused ''?'''
INSERT INTO #SpaceUsed 
EXEC sp_msforeachtable @command1=@str

SELECT TableName, NumRows, 
CONVERT(numeric(18,0),REPLACE(ReservedSpace,' KB','')) / 1024 as ReservedSpaceMB,
CONVERT(numeric(18,0),REPLACE(DataSpace,' KB','')) / 1024 as DataSpaceMB,
CONVERT(numeric(18,0),REPLACE(IndexSize,' KB','')) / 1024 as IndexSpaceMB,
CONVERT(numeric(18,0),REPLACE(UnusedSpace,' KB','')) / 1024 as UnusedSpaceMB
FROM #SpaceUsed
-- WHERE TableName IN ('[dbo].[Table1]','[dbo].[Table2]')
ORDER BY TableName asc

use DATABASENAME
GO
SELECT 
    t.NAME AS TableName,
    s.Name AS SchemaName,
    p.rows,
    --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 
    UnusedSpaceMB DESC, t.Name