This blog explains how to retrieve the byte sizes of tables that are present in current database. Use Below query to find out the size of tables.
Query:

  1. SELECT sob.name AS Table_Name,
  2. SUM(sys.length) AS [Size_Table(Bytes)]
  3. FROM sysobjects sob, syscolumns sys
  4. WHERE sob.xtype='u' AND sys.id=sob.id
  5. GROUP BY sob.name
Result: