Find the last used column

[Bob Phillips]

No, row 2, row 3 and row 4 are completely empty.....

If row 3 is empty, the last column is 0, so it is correct

When you say array enter i'm not totally sure what you mean.

When you enter a formula, normally you type it in, then hit the Enter key. With an array formula, you type it in, then hit Ctrl-Shift-Enter together. You will then see the formula in the formula bar surrounded by braces {=formula}. Those braces are automatic, you do not type them, or change them, except by the Ctrl-Shift-Enter.

I need this to be an automatic process with no manual intervention.

By virtue of being a worksheet formula, every time something in the target range changes, the formula will update.