i already looked around but couldnt find anything....

I am trying to create a loan amortization schedule that will show the
monthly payments for the term of the loan. how do i create it so that excel
automatically adds a cell for each month. Basically i am trying to set it up
so all i do is type in the loan amount, interest rate, term, and start date.
i know i can do it by dragging the auto fill button down and it will
automatically fill in the months but i dont want to have to do that everytime
i change the term. any help would be appreciated.