On SQL Server 2005 and greater, you can right-click on the database in Object Explorer, select reports, standard reports and run the disk usage by tables report. There are other reports available also.

The query that is used to populate this report is:

SELECT

(row_number() over(order by a3.name, a2.name))%2 as l1,

a3.name AS [schemaname],

a2.name AS [tablename],

a1.rows as row_count,

(a1.reserved + ISNULL(a4.reserved,0))* 8 AS reserved,

a1.data * 8 AS data,

(CASE WHEN (a1.used + ISNULL(a4.used,0)) > a1.data THEN (a1.used + ISNULL(a4.used,0)) - a1.data ELSE 0 END) * 8 AS index_size,

(CASE WHEN (a1.reserved + ISNULL(a4.reserved,0)) > a1.used THEN (a1.reserved + ISNULL(a4.reserved,0)) - a1.used ELSE 0 END) * 8 AS unused

FROM

(SELECT

ps.object_id,

SUM (

CASE

WHEN (ps.index_id < 2) THEN row_count

ELSE 0

END

) AS [rows],

SUM (ps.reserved_page_count) AS reserved,

SUM (

CASE

WHEN (ps.index_id < 2) THEN (ps.in_row_data_page_count + ps.lob_used_page_count + ps.row_overflow_used_page_count)

ELSE (ps.lob_used_page_count + ps.row_overflow_used_page_count)

END

) AS data,

SUM (ps.used_page_count) AS used

FROM sys.dm_db_partition_stats ps

GROUP BY ps.object_id) AS a1

LEFT OUTER JOIN

(SELECT

it.parent_id,

SUM(ps.reserved_page_count) AS reserved,

SUM(ps.used_page_count) AS used

FROM sys.dm_db_partition_stats ps

INNER JOIN sys.internal_tables it ON (it.object_id = ps.object_id)

WHERE it.internal_type IN (202,204)

GROUP BY it.parent_id) AS a4 ON (a4.parent_id = a1.object_id)

INNER JOIN sys.all_objects a2 ON ( a1.object_id = a2.object_id )

INNER JOIN sys.schemas a3 ON (a2.schema_id = a3.schema_id)

WHERE a2.type <> N'S' and a2.type <> N'IT'

ORDER BY a3.name, a2.name

The above can be modified to show the data in any order you need.