<prompt> Human: How do extra mortgage payments impact future payments?When I make an extra payment, I know that goes directly to principal and shortens my loan duration. However, does it also impact the ratio of interest to principal of future payments?I ask because early on, payments are mostly towards the interest on the loan and only a little towards principal. Over time this shifts. I am wondering if extra payments change this ratio - and if so, how is it calculated - immediately or at the end of the year?  <response>: Yes the ratio will be shifted more towards principal and it will take effect the following month. This is because the interest due any given month is calculated by simply take the monthly interest rate annual rate 12 times the remaining principal. 