Hi,
INCREMENT_BY is the next increment value for datafile autoextension. Multiply this value with you block size to get a byte value.
SQL> ALTER DATABASE
2 DATAFILE '/app/oracle/product/10.1.0/db_1/oradata/orcl/example01.dbf'
3 AUTOEXTEND ON NEXT 8M
4 /
Database altered.
SQL>
SQL> SELECT increment_by "Blocks", increment_by * (bytes/blocks) /1024/1024 "Meg"
2 FROM DBA_DATA_FILES
3 WHERE file_name = '/app/oracle/product/10.1.0/db_1/oradata/orcl/example01.dbf'
4 /
Blocks Meg
---------- ----------
1024 8
Best regards.
Frank