I have a 30 year mortgage and I'd like to make extra payments each month to speed up the amortization schedule. I thought this would be better than taking out a 15 year mortgage as it gives me some added flexibility in case I need it at some point. There are a lot of similar questions but I didn't find any that answered this specifically.
When making these extra payments, do I need to tell the bank that these payments should go towards the principal or will it happen automatically? I realize it sounds absurd that a bank would take an extra payment and apply it to interest which would be like stealing my money... but then again, these are banks we are talking about.
When I use a loan amortization calculator, that is the way that it treats my extra payments (applies them to principal) and so if I use this to model my amortization schedule, I want to be sure this is how it will work.
Thanks for your help in advance.