The below SQL script will return a list of tables in a database along with the table sizes in MB.

select object_name(id) [Table Name], 
[Table Size] = convert (varchar, dpages * 8 / 1024) + 'MB' 
from sysindexes where indid in (0,1) 
order by dpages desc

​You will get a report like the below;

SQL Report the disk size each table is using in a database