Calculations (pro-rate)

I need to pro-rate a dollar amount to number of attendees, however when I enter the formula in my spreadsheet and copy the formula down so when a new entry is recorded the formula is calculated several rows down the new record gets entered on the row after the last one the formula is in. How do you fix this?

I thought this would be the relevant forum, I know the formula that I need, I just am curious as to why when my user form creates an entry it inserts it on the first row after the last formula has been placed. Meaning, if cell A1 - A10 have the formula in the cells, when I enter a new record via my user form it places it in row 11 not in row 1 which is what I need it to do.

I would like for the user form to automatically calculate the prorated dollar and input that figure as part of the entry.

The formula that I have on my active sheet is: =IF(B1=0,"",A1/B1)
This was the formula given to me by another member of this forum some time ago.