What is a mortgage amortization schedule?

An amortization schedule is a table showing how each payment is split between interest and principal over the life of the loan. Early payments are mostly interest because the balance is high. As the balance drops, more of each payment goes to principal.

Why does so much of an early payment go to interest?

Each month, interest is calculated on the remaining loan balance. In the early years the balance is near the full loan amount, so the interest portion of the payment is large. As principal is paid down, the interest portion shrinks and the principal portion grows.

How does an extra principal payment affect the schedule?

Any extra principal payment reduces the loan balance immediately. Because future interest is calculated on the lower balance, every payment afterward applies more to principal. This compounds over the life of the loan and can cut years off the term.

Is my data shared with anyone?

Every calculation in this tool runs locally as JavaScript in your browser. Loan information stays in your browser.

Mortgage Amortization Schedule

Build a year-by-year amortization schedule for any mortgage. See how each annual payment is split between principal and interest, the remaining balance, and the cumulative interest paid. Understanding the amortization curve helps you decide whether extra principal payments are worth it.

Currency

Home price

Down payment

Interest rate (% per year)

Term (years)

Property tax (% per year, optional)

Home insurance ($ per year, optional)

Formula: M = P[r(1+r)^n] / [(1+r)^n - 1], where P = loan amount, r = monthly rate, n = months

How it works

After M = P[r(1+r)^n] / [(1+r)^n - 1] gives the level monthly payment, the schedule walks every month in order. Each iteration computes the interest portion as the remaining balance times r, treats the rest of the payment as principal, and subtracts that principal from the balance for the next month. The results are aggregated into annual rows so you can see exactly when the principal share overtakes the interest share and how the remaining balance falls over time.

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Every calculation runs locally in your browser as JavaScript. No loan amounts, interest rates, or amortization details leave your device at any point. You can check this yourselfin your browser's DevTools Network tab.

Calculations are estimates for informational purposes only. Consult a financial professional for advice.

Frequently asked questions

What is a mortgage amortization schedule?: An amortization schedule is a table showing how each payment is split between interest and principal over the life of the loan. Early payments are mostly interest because the balance is high. As the balance drops, more of each payment goes to principal.
Why does so much of an early payment go to interest?: Each month, interest is calculated on the remaining loan balance. In the early years the balance is near the full loan amount, so the interest portion of the payment is large. As principal is paid down, the interest portion shrinks and the principal portion grows.
How does an extra principal payment affect the schedule?: Any extra principal payment reduces the loan balance immediately. Because future interest is calculated on the lower balance, every payment afterward applies more to principal. This compounds over the life of the loan and can cut years off the term.
Is my data shared with anyone?: Every calculation in this tool runs locally as JavaScript in your browser. Loan information stays in your browser.

Mortgage Amortization Schedule

How it works

Processing runs in your browser

Frequently asked questions

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