<prompt> Human: Ive always thought that mortgages work like a savings account: however large the pile of loaned money is whether me loaning to the bank or the bank loaning to me, the interest paid is based on that amount. Based on that, I thought it was important to pay down principal as quickly as possible, then later when the unpaid principal is smaller its not as important.It turns out that you pay a fixed amount of interest per day for the life of the loan, no matter how much principal you owe. Ignoring minimum payments, you could pay 99,999 the first day on a 100,000 mortgage and the final dollar the last, or a dollar the first day and 99,999 the last and youd still owe the same interest.I feel so stupid!EDIT: I think Ive figured out why Im confused. I got a 250,000 loan for the house about 5 years ago and have been paying ahead all along. Last February I refinanced on the last 70,000 remaining at 3.25. It only cost me 200 to do it. It was a 5 year in-house retail loan with BBT. I guess its not amortized like a regular mortgage? I have a great deal of difficulty with financial matters like this. I just saw the low interest rate and low closing cost and didnt consider that there could be other parameters. I live below my means so hope to have it paid off in the next year or so.Thanks to all who commented. Im not crazy after all!  <response>: Thats not how most mortgages work, but youd have to actually read the loan agreement to know how yours works. 