Excel automatically creates a calculated column when you enter a formula in an empty table column. When you use calculated columns, you’ll need to enter a formula only once and it automatically fills down the column—there’s no need to use the Fill or Copy command. In addition, a calculated column continues to adjust as you add or delete rows in the table so that the formula is immediately extended to those rows.
To create a calculated column in a table:
Click a cell in an empty column that you want to use as the calculated column.
Tip: If necessary, insert a new column in the table. Right-click the column to the right of where you want to add the blank column, and choose Insert Columns.
Type the formula you want to use, and press ENTER.
Note: If you type a formula in a cell that already has data, it doesn’t create a calculated column.
In the below example, the SUM formula in cell D2 was automatically filled down all the cells in the calculated column D.
Edit a calculated column
To update a calculated column, click any cell in the calculated column and edit the formula in that cell and press ENTER.
Delete a calculated column
Right-click the calculated column, and click Delete Columns.