How to estimate table size

Once you create a table, you can estimate the table size using command sp_estspace.

To estimate the amount of space required by a table and its indexes:
1. Create the table.
2. Create all indexes on the table.
3. Run sp_estspace, giving the table name, the estimated number of rows for the table, and the optional arguments, as needed.



You do not need to insert data into the tables. sp_estspace uses information in the system tables--not the size of the data in the tables--to calculate the size of tables and indexes.

Example :
sp_estspace TableA, 50000

where TableA is table name and 50000 is estimated rows in the table.

Further details can be found in Sybase Manuals