Definition
Amortization is the schedule that determines how each mortgage payment gets split between interest and principal over the life of the loan. In the earliest years, the bulk of every payment goes toward interest, which means your loan balance drops very slowly at first and then accelerates in later years. This explains a common surprise for homeowners: someone five or six years into a 30-year loan often finds they still owe nearly what they originally borrowed. For a seller, understanding amortization matters because it directly shapes how much equity you actually have available when it's time to sell. Simply totaling up your monthly payments over the years won't tell you your real payoff amount — you need an actual payoff quote from your loan servicer. This is especially important for anyone assuming years of payments automatically translate into significant home equity.
Example
Six years into his $250,000 mortgage at 6% interest, Anthony calculated he'd made roughly $110,000 in total payments, so he assumed he'd knocked his balance down significantly. When he requested an actual payoff quote from his servicer, though, it showed he still owed close to $225,000. He pulled up his amortization schedule and saw that in the early years, over 80% of each payment had gone toward interest rather than principal. Looking at the schedule year by year, he could see the split only really started shifting in his favor after about year twelve. That realization changed how he thought about his equity heading into a possible sale, and he decided to get a real payoff quote before assuming any specific number about what he'd walk away with.