What is an amortization schedule?

A table detailing each periodic payment, showing the exact amount going to interest, principal, and the remaining loan balance.

Does paying extra shorten the amortization cycle?

Yes! Paying extra directly reduces the principal balance, avoiding future compounded interest and shortening the overall life of the loan.

Mortgage Amortization: How Your Payments Work

What is Mortgage Amortization?

Amortization is the process of spreading a loan into a series of equal periodic payments. Although each payment is identical, the ratio of what goes towards interest versus principal changes over time.

How the Math Works

In the early years of a 30-year fixed mortgage, the vast majority of your monthly payment is devoured by interest. This is because your outstanding loan balance is at its highest, and interest is computed monthly based on that high balance.

As you slowly pay down the principal, the monthly interest charge decreases, allowing a larger portion of your next payment to reduce the principal.

The Standard Amortization Formula

\text{Monthly Payment } (M) = P \times \frac{r(1+r)^n}{(1+r)^n - 1}

Where:

P = Principal loan amount

r = Monthly interest rate (annual rate divided by 12)

n = Total number of payments (months)

The Amortization Curve

If you plot interest vs. principal payments over 30 years, you will see two crossing curves:

Year 1-15: Interest dominates. On a $300,000 loan at 6%, you pay more interest than principal for the first 14 years.

Year 15: The tipping point where more than 50% of your payment finally goes toward principal.

Year 30: Virtually 100% of your payment is going straight to principal.

How to Save Thousands on Interest

You can bypass the slow front-loaded interest of amortization schedules with these methods:

1. Bi-weekly Payments: Paying half your monthly mortgage amount every two weeks results in 13 full payments per year (one extra month), slashing 4 to 5 years off a 30-year term. 2. Extra Principal Payments: Even an extra 50 or 100 per month paid directly to the principal reduces the compound base interest drastically over the loan life.