How to determine how much storage space a column takes in Oracle? How to determine how much storage space on the disk a column takes in a table in Oracle?

I'm running Oracle 11gR2 11.2.0.3.
You can use the VSIZE to get the number of bytes for the internal representation of a value.

If you want the total space used by a column, you'll need to sum over all the rows (unless the type used has a fixed length).

The DUMP function will also give you the size and raw representation of a value, but not in a format amenable to easy summation.