The following query gives a sizes of tables and number of records for the database:

select o.name
, reservedpages = sum(a.total_pages)
, usedpages = sum(a.used_pages)
, pages = sum(case when a.type <> 1 then a.used_pages
when p.index_id < 2 then a.data_pages else 0 end)
, SUM(a.used_pages)*8096 AS 'Size(B)'
, rows = sum(case when (p.index_id < 2) and (a.type = 1) then p.rows else 0 end)
from sys.objects o
join sys.partitions p on p.object_id = o.object_id
join sys.allocation_units a on p.partition_id = a.container_id
where o.type = 'U'
group by o.name
order by 3 desc

or similar:

SELECT
t.NAME AS TableName,
p.rows AS RowCounts,
SUM(a.total_pages) * 8 AS TotalSpaceKB,
SUM(a.used_pages) * 8 AS UsedSpaceKB,
(SUM(a.total_pages) - SUM(a.used_pages)) * 8 AS UnusedSpaceKB
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
WHERE
t.NAME NOT LIKE 'dt%'
AND t.is_ms_shipped = 0
AND i.OBJECT_ID > 255
GROUP BY
t.Name, p.Rows
ORDER BY
3 DESC