Mortgage amortize, stop calculations at end of term

[scott]

Hello.
I have 3 entry fields.
B1 Amount borrowed
b2 Rate
b3 Term

This calculates an annual payment


I have 7 columns as follows: A - G.
(Year) (rate) (interest) (princ) (total payout)
(balance) (add.prin)

I have it entered so it amortizes annually, and I have 40
rows to accomodate a 40 year term if necessary. If I
enter a 20 year term, I would like to have rows 21 - 40
dissappear. As I have it now they just continue into an
inverted amortization. Thanks for any help.