Loans & Credit
Published July 9, 2026
Ever wondered why, after a year of mortgage payments, your balance has barely moved? The answer is amortization — the schedule that governs how a loan is repaid. Understanding it reveals where your money actually goes each month and, crucially, how a few extra payments can save you a fortune in interest.
Amortization is the process of paying off a loan with a series of regular, equal payments over a set term. Each payment is the same amount, but its internal split between interest and principal changes over time. Common amortized loans include mortgages, car loans, and personal loans.
Here's the key idea: interest is charged on your current outstanding balance. At the start of the loan, the balance is at its highest, so the interest portion of each payment is large and the principal portion is small. As you chip away at the balance, the interest shrinks and more of each fixed payment goes toward principal.
The mechanics for each period:
Interest = Balance x Periodic RatePrincipal = Payment - InterestNew Balance = Balance - Principal
Imagine a $200,000 mortgage at 6% over 30 years, with a fixed monthly payment of about $1,199. Watch how the split shifts:
| Payment | Goes to Interest | Goes to Principal |
|---|---|---|
| Month 1 | ~$1,000 | ~$199 |
| Month 180 (year 15) | ~$700 | ~$499 |
| Month 360 (final) | ~$6 | ~$1,193 |
In month one, 83% of your payment is interest. By the final payment, almost all of it is principal. This front-loading of interest is exactly why early balances fall so slowly — and why it's called an amortization "curve."
Enter your loan amount, rate, and term to generate a payment-by-payment breakdown of principal, interest, and remaining balance.
Use the Loan Amortization Calculator →Because interest is charged on the balance, anything that lowers the balance faster saves you interest on every future payment. Extra payments go 100% to principal, so they punch above their weight — especially early in the loan when the balance (and therefore the interest) is highest.
On that $200,000 mortgage, adding just $100 a month to the payment can cut years off the loan and save tens of thousands in interest. The earlier you start, the bigger the effect, because you're removing principal that would otherwise accrue interest for decades.
Watch out for negative amortization, where a payment is too small to cover even the interest, so the balance actually grows. Well-structured loans avoid this.
Paying off a loan through regular equal payments, each covering that period's interest plus some principal, until the balance reaches zero.
Interest is charged on the outstanding balance, which is highest at the start — so early payments are mostly interest and later ones mostly principal.
Each period: interest = balance x periodic rate; principal = payment − interest; new balance = balance − principal. Repeat until zero.
Yes — extra payments go straight to principal, cutting future interest and shortening the term, especially when made early.
Amortization explains the whole life of your loan: why early payments feel like they barely dent the balance, and why extra principal payments are so powerful. See exactly where your money goes with the Loan Amortization Calculator, then use the Loan EMI Calculator to test how a shorter term or extra payment could save you thousands.
This article is for educational purposes only and is not financial advice. See our Disclaimer.