If you realllllllllllly need it in excel…

http://office.microsoft.com/en-us/templates/mortgage-amortization-schedule-TC001056620.aspx

http://download.cnet.com/Amortization-Schedule-for-Excel/3000-2057_4-10902935.html

I could write the formula for you, but I’m lazy. Why invent the whell, when someone has it already done it for you..