Amortization calculator for loans or creditcards. It also calculates correctly when change/adjustment occurs upon the remaining principal, remaining terms and interest rate. That saying, this is an utility for your plan, adjustment and decision.

= Just change the plans in script as your own plans, =

ex. plans = [ ## date(Y,M,D), $500k, months of 20 years, monthly interest rate by percentage. (datetime.date(2013,4,27), 500000, 2012, 6.55/12.0/100.0),
(datetime.date(2015,1,27), 0,0, 6.15/12.0/100.0), (datetime.date(2015,4,27), 0-200000,0-1012, 6.15/12.0/100.0), ]

look the 3rd item, there are adjustments on the principal (pay 20K in advance) and terms (reduced 10 years in term).

python 2.7+ required.