Tables size in mssql

To check size used by data and indexes You can use following script

SELECT
  Col.Column_Name
 ,Col.Table_Name
 ,OBJECT_ID(Col.Table_Name) AS [object_id]
FROM
  INFORMATION_SCHEMA.TABLE_CONSTRAINTS Tab
 ,INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE Col
WHERE
  Col.Constraint_Name = Tab.Constraint_Name
  AND Col.Table_Name = Tab.Table_Name
  AND Constraint_Type = 'PRIMARY KEY'
  AND [Col].Table_name='YOUR_TABLE_NAME'

or more complicated (with index size)

DECLARE @tname nvarchar(128) = ''
set nocount on

--creating temp tabele
IF EXISTS (select * from tempdb..sysobjects where name like '#tblinfos%')
 DROP TABLE #tblinfos

CREATE TABLE #tblinfos(
 [name] [nvarchar](128) NOT NULL,
 [rows] [char](11) NOT NULL,
 [reserved] [varchar](18) NOT NULL,
 [data] [varchar](18) NOT NULL,
 [index_size] [varchar](18) NOT NULL,
 [unused] [varchar](18) NOT NULL
)

--cleaning table infos
TRUNCATE TABLE #tblinfos

DECLARE @name nvarchar(128)
--createing cursor
DECLARE tables CURSOR FOR SELECT name FROM dbo.sysobjects WHERE (OBJECTPROPERTY(id, N'IsUserTable') = 1) AND (uid = 1) AND (name like @tname + '%')
OPEN tables

FETCH NEXT FROM tables INTO @name

WHILE (@@FETCH_STATUS = 0)
BEGIN
 INSERT INTO #tblinfos EXEC('sp_spaceused ''' + @name + '''')
 FETCH NEXT FROM tables INTO @name
END

CLOSE tables
--deallocating cursor
DEALLOCATE tables
UPDATE #tblinfos SET
 [reserved] = REPLACE([reserved],' KB',''),
 [data] = REPLACE([data],' KB',''),
 [index_size] = REPLACE([index_size],' KB','') ,
 [unused] = REPLACE([unused],' KB','') 
SELECT * FROM (
SELECT 
 [name],
 convert(int,[rows]) as [rows],
 round(convert(float,[reserved])/1024,2) as [reserved],
 round(convert(float,[data])/1024,2) as [data],
 round(convert(float,[index_size])/1024,2) as [index_size],
 round(convert(float,[unused])/1024,2) as [unused]
 FROM #tblinfos 
UNION
SELECT 
 'SUM' as [name],
 sum(convert(int,[rows])) as [rows],
 sum(round(convert(float,[reserved])/1024,2)) as [reserved],
 sum(round(convert(float,[data])/1024,2)) as [data],
 sum(round(convert(float,[index_size])/1024,2)) as [index_size],
 round(sum(convert(float,[unused])/1024),2) as [unused]
 FROM #tblinfos
) as tbl 
ORDER BY [reserved] DESC,[data] DESC, [name] ASC

--droping temp table
DROP TABLE #tblinfos