Mortgage Amortization Calculator

A mortgage amortization calculator turns your loan into a full repayment schedule. It shows every year of the loan, how much of your payment goes to interest, how much goes to principal, and what balance is left. Amortization is just the word for paying a loan down in equal installments over time.

The payment itself never changes on a fixed-rate loan. What changes is the split inside it. This tool makes that split visible, which is the part a single payment figure hides.

Who Uses an Amortization Schedule

• New buyers who want to see where their money actually goes each year.
• Owners planning extra payments who want to watch the balance drop faster.
• Anyone selling soon who needs to know their remaining balance at a future date.
• Budgeters checking how much equity they build in the first five years.

If you still need the full payment with taxes and insurance, start at the mortgage calculator and bring the loan amount here to see the schedule.

You give the tool three numbers and it builds the whole schedule month by month, then groups the result by year so it is easy to read.

1. Enter the loan amount. This is what you borrow after your down payment.
2. Enter the interest rate. Use your fixed annual rate.
3. Pick the term. Choose 30, 20, 15, or 10 years.

Open Advanced settings to add an extra monthly payment or to label the rows with real calendar years. The extra payment goes straight to principal, which shortens the loan and cuts total interest.

Reading the Schedule Table

Each row is one year. The interest column falls every year while the principal column rises. The balance column shows what you still owe at the end of that year. The year where principal first beats interest is a useful milestone, and the tool calls it out for you.

Interest is charged on the balance you still owe. At the start, that balance is at its highest, so the interest slice is large. As you pay the balance down, the interest slice shrinks and more of each payment attacks the principal.

On a $320,000 loan at 6.5% over 30 years, the first payment is $2,022.62. Of that, $1,733.33 is interest and only $289.28 pays down the balance. By the final year, almost the entire payment is principal.

These figures come from an independent script that builds the full month-by-month schedule and confirms the balance reaches exactly zero at the final payment.

Two small equations run in a loop, one row per month.

• Monthly payment uses the standard loan formula: M = P × r(1+r)^n ÷ ((1+r)^n − 1)
• Interest for the month = current balance × monthly rate
• Principal for the month = payment − that interest
• New balance = old balance − principal

The loop repeats until the balance hits zero. The monthly rate is your annual rate divided by 12, and the number of payments is the term in years times 12.

What an Extra Payment Does

An extra payment adds directly to the principal step. That larger principal cut means next month’s balance is smaller, so next month’s interest is smaller too. The effect compounds, which is why even a small extra amount can remove years from the loan. To focus on that scenario, the mortgage payoff calculator is built around it.

Every principal dollar you pay becomes equity, your ownership stake in the home. The schedule is really an equity-building timeline read from the other side.

Because early payments are mostly interest, equity builds slowly at first. This matters if you plan to sell or refinance in the first few years, since you will have paid down less of the balance than the number of payments might suggest.

Equity, Refinancing, and PMI

Two milestones depend on your balance. Reaching 20% equity is when private mortgage insurance can come off, which is worth tracking as the balance falls. Refinancing also resets amortization to a brand new schedule, so a mortgage refinance in year eight starts the interest-heavy phase over again unless you shorten the term.

Because interest rides on the balance, anything that lowers the balance sooner saves interest. Three approaches all work through the same mechanism.

Switching to a biweekly rhythm quietly adds one extra payment a year. To see exactly how much time and interest that saves on your loan, use the biweekly mortgage calculator.

A Word of Caution on Extra Payments

Extra principal is only worth it after higher-interest debt is gone and your emergency fund is set. A mortgage is usually the cheapest debt you carry, so pay it down faster only once the more expensive goals are handled.

Assuming Half the Term Means Half Paid Off

It does not. Because early payments are interest-heavy, you owe far more than half the balance at the halfway point. Read the actual balance from the schedule.

Forgetting Taxes and Insurance

Amortization covers principal and interest only. Your real monthly payment also includes escrow items. Use the full mortgage calculator for that number.

Ignoring the Refinance Reset

Refinancing starts a new amortization schedule. A lower rate helps, but a fresh 30-year term restarts the interest-heavy phase. Match or shorten the term to keep your progress.

Treating the Estimate as Your Statement

This schedule assumes a fixed rate and on-time payments. Your lender’s statement is the record of truth. Use this to plan, not to reconcile.

The schedule math here is standard and exact. Use these primary sources to check definitions and rules:

• CFPB Owning a Home explains amortization, escrow, and loan terms from the federal consumer regulator.
• Investor.gov Calculators from the SEC cover loan and compounding math.
• Fannie Mae documents servicing, escrow, and PMI cancellation rules.

Your lender’s amortization statement reflects your exact loan terms and any rounding they apply. Use it as the final record.