Loan Amortization

I need a calculator or a spreadsheet of amortization of the loan that will allow me to enter graduate payments (eg 12-month $ 50 followed by 36 months @ $ 100, etc.). I try to picture and Chart a payment for my student loans. The online calculators I found you a serial input of payments.

I am not aware of the amortization calculators good as the one you mentioned in line (although I wish there was!)

I have become very good at using Excel to creat this kind of thing. It is certainly possible to do with Excel.