Amortization

Definition

Amortization is the process of paying off a loan through a series of fixed, regular payments over a set period of time. Each payment covers both interest and a portion of the principal (the original loan balance).

How amortization works

With a fully amortized loan (like a standard 30-year mortgage), your monthly payment stays the same throughout the loan — but the split between interest and principal shifts over time.

In the early years, most of your payment goes toward interest because you owe a large balance. As you pay down the principal, less interest accrues each month, so more of your fixed payment goes toward reducing the balance. By the final years of the loan, most of each payment is principal.

Example with a $300,000 mortgage at 6.5% for 30 years (monthly payment ≈ $1,896):

• Payment 1: ~$1,625 interest / ~$271 principal
• Payment 180 (year 15): ~$1,300 interest / ~$596 principal
• Payment 360 (year 30): ~$10 interest / ~$1,886 principal

The amortization schedule

An amortization schedule is a table showing every payment over the life of the loan — how much goes to interest, how much to principal, and what the remaining balance is after each payment. Our mortgage calculator generates a year-by-year amortization schedule automatically.

Why it matters

• Building equity: Early in a mortgage, you build equity slowly because most payments are interest. Understanding this helps set realistic expectations.
• Extra payments: Making extra principal payments early in the loan has an outsized impact — it reduces the balance that future interest is calculated on, potentially saving tens of thousands of dollars and years off the loan.
• Refinancing: If you refinance years into your loan, you reset the amortization schedule — meaning you may end up paying more interest over the long run even if your rate drops.

Other uses of amortization

In accounting, amortization also refers to the gradual expensing of intangible assets (like patents or goodwill) over their useful life — similar in concept to depreciation for physical assets. In everyday personal finance, amortization almost always refers to loan repayment.