Amortization Calculator

The Amortization Calculator builds a full year-by-year payment schedule for any fixed-rate loan, showing exactly how much of each payment goes toward principal versus interest.

How amortization works

Each monthly payment is the same fixed amount, but the split between principal and interest changes over time. Early payments are mostly interest (since the balance is high); later payments are mostly principal. Interest for a given month is calculated as:

Interestmonth = Remaining Balance × Monthly Rate

The rest of the fixed payment reduces the principal balance for the next month.

Example: On a $250,000 loan at 6.5% over 30 years, the first year's payment of about $18,972 includes roughly $16,150 in interest and only $2,822 in principal — but by year 30, nearly the entire payment goes to principal.

Why this matters

Understanding amortization helps you see the real cost of extending a loan term, and shows how extra principal payments early on can save significant interest. Pair this with the Mortgage Calculator or Loan Calculator to explore different scenarios.

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