Amortization Calculator

The first payment on $250,000 at 6.5% is $1,354 interest and $226 principal

Amortization is the gradual reduction of a loan balance through scheduled payments, and the ordering inside each payment is the whole story: interest on the current balance is covered first, and only what is left reduces principal. A $250,000 loan at 6.5% over 30 years produces a monthly payment of $1,580.17. The very first payment is $1,354.17 interest and just $226.00 principal — roughly 86% interest — which is why the balance barely moves early on. Over the full term, total interest comes to about $318,862, more than the original loan itself, for a total paid of about $568,862.

The payment stays fixed for the whole term, but what it buys changes every row. Early rows are interest-heavy because the balance is largest at the start; later rows are principal-heavy as the balance — and the interest charged on it — shrinks. The yearly summary rolls that up so you can read the trend without scrolling hundreds of rows.

One payment formula, four period rates: ÷ 12, ÷ 26, ÷ 52, ÷ 24

r is the period rate, and the frequency selector is what sets it: annual rate ÷ 12 for monthly, ÷ 26 for biweekly, ÷ 52 for weekly, ÷ 24 for semi-monthly, with n counted on the same basis. Inside every period the fixed payment covers interest first; the remainder, plus any extra principal, reduces the balance. The final payment is trimmed so the balance ends at exactly zero, and an extra payment is capped at the remaining balance so it can never overshoot. Everything below the payment line is arithmetic on the figures you enter: estimates, not a lender quote.

$100 a month buys back 4.7 years and $58,000

On that same 30-year $250,000 loan at 6.5%, adding $100 a month to principal pays it off roughly 4.7 years early and saves about $58,000 in interest. The leverage is in the timing, not the size: because interest is charged on the outstanding balance, a dollar paid early erases interest for every remaining year, so $100 applied in year 25 is worth a fraction of $100 applied in year 1.

The scenario table prices your own version of that trade. It puts the base loan, an extra-payment plan and a shorter term side by side, which is the fastest way to see what a few hundred extra dollars a year is actually worth before you commit to them. Read your note for a prepayment penalty first, because a lender fee for paying early can cancel the saving this schedule shows.

A real biweekly is the rate ÷ 26, not half the monthly payment

Biweekly amortization uses a period rate of annual rate ÷ 26. With 26 payments a year you make the equivalent of 13 monthly payments instead of 12, and the extra amount goes to principal. This calculator computes that properly: it does not simply halve the monthly payment, which would give the wrong payment amount and understate the savings. Some lender biweekly programs do exactly that, remitting twelve payments a year, and save no interest at all. Switch the frequency selector and compare the payoff date against the monthly base to see which of the two you are being offered.

The note rate builds the schedule; the APR only ranks the offers

The interest rate determines your payment and therefore every row below it. The APR folds that same rate together with certain loan fees into one yearly figure, which makes it the better number for comparing two offers, and lenders are required to disclose it. Use the rate to build the schedule and the APR to choose the lender. The optional APR and fees estimator here is a planning aid, not an official APR disclosure, and it deliberately does not feed the schedule: change it and not one payment row moves.

The row where the balance reaches 80% of the purchase price cancels your PMI

PMI, private mortgage insurance, is required on conventional loans when the down payment is below 20%, and the lender cancels it automatically once the balance reaches 80% of the original home value — typically somewhere around year 9 to 11 on a 30-year loan at standard rates. The schedule replaces that rule of thumb with a date: scan the balance column for the first row where balance ÷ original value falls to 80%, and extra payments visibly pull that row forward. The monthly add-ons for property tax, insurance, PMI and HOA sit outside the amortization itself; they raise your total monthly cost without touching the principal-and-interest rows the payoff date is built from.

Eight currencies, six sheets: the schedule leaves the page intact

Switch to INR, GBP, EUR, CAD, AUD, SGD or AED and every figure redisplays in that currency, the schedule and the Excel export included, while the underlying amortization math stays the same. The full payment-by-payment schedule exports as CSV or as part of the six-sheet Excel workbook, and the on-page table prints straight from the browser.

A balloon, a rate reset or a lender’s own rounding breaks this schedule

This page assumes a fixed rate and a loan that pays down to exactly zero at the end of the term. It does not model a balloon payment or a lease’s residual value, both of which rewrite the final payment, and it cannot model a variable or resetting rate. It also leaves out lender fees, escrow, property taxes, insurance, late payments and lender-specific compounding rules, so a servicer’s printed schedule can differ row by row even when the inputs match. Those limitations are structural rather than a rounding gap, and the results depend entirely on the values you enter. For an ordinary fixed-payment loan with no balloon it works exactly as built, a car loan included, though the Auto Loan Calculator goes further on trade-ins and rebates.

Related calculators

Amortization underlies most loans — these related tools build on the same math:

More in Finance, or browse all calculators.

Read the guides

For why early payments barely touch the balance, and how extra payments change that, see How Amortization Works: Principal, Interest, and Loan Balance Explained.

For how this schedule fits into the full cost of a home purchase, see Mortgage Payment vs Total Loan Cost: What Borrowers Often Miss.

Sources and methodology

Every row in this schedule is arithmetic on the figures you enter — this page fetches no live rates, escrow amounts or lender fees. The sources below cover the fixed-payment formula that builds the schedule, the interest-and-principal split each payment is divided into, the effect of an extra principal payment on the payoff date, and the prepayment penalty that can cancel that saving. Links open in a new tab.

• What is amortization? — the regulator explanation of how one fixed payment splits into interest and principal, which is exactly what every row of this schedule showsConsumer Financial Protection Bureau · verified 2026-09-01
• How do mortgage lenders calculate monthly payments? — the fixed-payment formula this page uses to derive the payment the whole schedule is built fromConsumer Financial Protection Bureau · verified 2026-09-01
• How does paying down a mortgage work? — why the early rows are almost all interest, and how an extra principal payment moves the payoff date, the effect the extra-payment inputs modelConsumer Financial Protection Bureau · verified 2026-09-01
• Interest rate vs APR — why the rate that builds this schedule is the note rate, not the APR quoted on the same loanConsumer Financial Protection Bureau · verified 2026-09-01
• What is a prepayment penalty? — the lender fee that can cancel the interest saving this page shows for paying extra or paying off earlyConsumer Financial Protection Bureau · verified 2026-09-01