calculate maximum size in bytes of a table row

how can i calculate the maximum amount of bytes that can be occupied by a table row.
The table might not have any data in it, i'm looking for a calculation based on the data types used for columns.All i found so far was algorithms to estimate the average size for existing rows. i'm trying to spool the contents of some of my tables to flat files, and for that i'm trying to figure out if the rows would not be truncated by sqlplus due to its bytes/line limitation by calculating the maximum size a row can reach in bytes. database version is 10g R2 running on RHEL 4 Received on Fri Apr 18 2008 - 07:24:53 CDT