Duplicate/Expand column formula when rows are added?

This is stupid, I used to know how to do this but for some reason it is not working.

I simply have a ton of columns with data, I input new data daily. The very last column is a custom column that has a formula combining info from other columns.
What I need is for the formula to autoexpand when I add new rows.


The alternative is just to copy that formula down 500 rows or so until I get to there and then do that again..but I know thats not the best way. - Thanks in advance and sorry for such a stupid question, I know it't basic.

Originally Posted by shirleyxls

You could convert your range to a table (Insert > table and follow the prompts).

This would automatically expand the range and copy all the formulas every time you add anything to the bottom.

That must have been how I did it before, let me try thanks