LOOKUP Last entry in a column

I am using the formula =LOOKUP(2,1/(1-ISBLANK(H:H)),H:H) in cell H1

to give me the last entry in column H which enters into a fixed location at the top of that column in H1. I then can use the cell H1 later in other calculations.

The problem is that the formula only works if column H is one that I fill in the entry manually.

If I use down the length of that column formulas which get that entry from another calculation from other cells, then the cell at the top (H1) where I want the last entry shown, is just blank.

How can I alter the ISBLANK function in my formula to solve this problem? Or do I need to use a different formula for this?

Thanks, Dennis

Or try:

=LOOKUP(2,1/(H2:H100<>""),H2:H100)