● Mortgage · Personal loan · Auto

Loan Amortization Calculator

Find your exact monthly payment, total interest cost, and full amortization schedule for any fixed-rate loan.

A $300,000 mortgage at 7% for 30 years has a monthly payment of $1,995.91 and costs $418,528 in interest over the life of the loan. This calculator shows the complete amortization schedule — every payment, principal, and interest row.

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Loan amount · Interest rate · Term · Extra payment

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Loan details

Loan amount

Annual interest rate

Loan term

years

Extra monthly payment (optional — goes to principal)

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Summary

Monthly payment

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Total of all payments

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Total interest paid

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#	Payment	Principal	Interest	Balance

How it's calculated

The amortization payment formula

Every fixed-rate loan uses the same formula to calculate the constant monthly payment that will pay off the loan exactly on the last payment date.

Monthly payment = P × r / (1 − (1+r)^-n) Where: P = principal (loan amount) r = monthly interest rate = annual rate ÷ 12 n = total payments = years × 12 Each month: Interest portion = remaining balance × r Principal portion = payment − interest New balance = balance − principal portion

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Monthly interest rate
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Monthly payment
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Total cost
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Amortization: The process of paying off debt with regular payments. Each payment covers interest first; the remainder reduces principal.
Principal: The original loan amount — what you actually borrowed, excluding interest.
APR (Annual Percentage Rate): The annual cost of borrowing including interest and fees. Always compare APR, not just the stated interest rate.
Extra payment: Any amount paid beyond the required monthly payment. Goes entirely to principal, reducing interest costs and shortening the loan term.

🔢 Worked example

A $200,000 mortgage at 6% over 30 years has a payment of about $1,199/month. Over the full term you pay ~$431,700 — about $231,700 in interest, more than the loan itself.

Disclaimer: this calculator assumes a fixed interest rate and constant monthly payments. Adjustable-rate loans, balloon payments, or other structures will differ. Always verify with your lender. Always confirm with an official source before deciding.

Frequently asked questions

How does amortization work?

In an amortizing loan, each payment covers the month's interest on the remaining balance, and the rest reduces principal. Because the balance decreases each month, the interest portion shrinks while the principal portion grows — even though the total payment stays constant.

Does paying extra save money?

Yes — dramatically. Extra payments go directly to principal, which immediately reduces future interest. On a $300k 30-year loan at 7%, an extra $100/month saves ~$40k in interest and cuts roughly 5 years off the term. Use the extra payment field to see your savings.

What is the difference between APR and interest rate?

The interest rate is the annual cost of the loan principal. APR includes the interest rate plus fees (origination, points, mortgage insurance, etc.), spread over the loan term. APR is the more complete measure for comparison shopping.

Can I use this for any loan type?

Yes — any fixed-rate, fully amortizing loan: mortgage, auto loan, personal loan, student loan. For adjustable-rate mortgages (ARMs), use the initial fixed rate for the fixed period, but understand your payment will change when it adjusts.

What is an amortization schedule?

An amortization schedule lists every payment of a loan, showing how much goes toward principal vs interest each period. In the early years of a loan, most of the payment is interest. Over time, the principal portion grows while interest shrinks — this is called amortization.

How is the monthly payment calculated?

Monthly payment = P × [r(1+r)^n] / [(1+r)^n − 1], where P = principal, r = monthly interest rate (annual rate ÷ 12), n = number of monthly payments. This formula ensures the loan is exactly repaid at the last payment.

Does making extra payments save interest?

Yes — significantly. Any extra payment goes directly to principal, reducing the balance on which future interest accrues. Paying an extra $100/month on a $300k 30-year mortgage at 7% saves approximately $40,000 in interest and cuts 5 years off the loan.

Are my results saved? Do I need an account?

No account or sign-up needed. Every calculation is saved automatically in your own browser, and you can also pin a result with the save button. Nothing is sent to any server: the data stays on your device and can be erased at any time with the clear button.

How do I track my progress over time?

From the fourth entry onward a “View comparison chart” button appears, opening a line chart with every entry in time order plus an indicator panel: total change, average per entry, lowest and highest value and the period covered. You can also export the history as CSV.

About this calculator

This loan amortization calculator turns a loan amount, interest rate, and term into a fixed monthly payment and a complete repayment schedule. It works for mortgages, auto loans, and personal loans — any loan repaid in equal installments — and shows how much of each payment goes to interest versus principal.

Early in the loan, most of each payment covers interest and little reduces the balance; over time that ratio flips and principal is paid down faster. Reading the schedule this way shows why extra payments early on save the most interest, and the total-interest figure reveals the real cost of borrowing beyond the amount you originally received.

By Vinicius Fonseca · Reviewed against official sources · Updated Jul 2026 · How we calculate →