What amortization is
Amortization is the process of repaying a loan over time through scheduled, usually equal, payments. Each payment is split between interest on the remaining balance and a portion of the principal. As the balance falls, the interest share of each payment shrinks and the principal share grows, even though the total payment stays the same.
How the schedule works
An amortization schedule lists every payment over the life of the loan:
- Early payments are weighted heavily toward interest, because the balance is large.
- Later payments pay down more principal, because the balance has dropped.
- The final payment clears the remaining balance to zero.
For example, on a 30-year mortgage, the first year's payments are mostly interest, while the last year's are almost entirely principal.
Why it matters
Understanding amortization helps borrowers see how much of their money goes to interest versus building equity, and why making extra principal payments early can save a large amount of interest overall. It also explains why selling a home in the first few years leaves little principal paid down. The total interest depends on the rate, the term, and the loan amount, which is closely tied to the APR. To build a full payment schedule for your own numbers, use the WhatIP loan-calculator or mortgage-calculator.