Amortization Calculator

$
%
Options — term unit, extra payment
$
Monthly payment —
Total interest — over the loan
Payoff time — until balance is zero

Amortization is how a fixed-rate loan is paid off: one equal payment each period, split between the interest accrued on the current balance and a slice of principal that shrinks what you owe. This calculator builds the full schedule — every payment broken into principal and interest with the running balance — and reports the monthly payment, total interest and payoff time. View it year by year or month by month, and add an extra monthly payment to see how many months and how much interest you save.

How to Build an Amortization Schedule

Three inputs, and every payment is mapped out for you.

1

Enter the loan

Type the amount borrowed, the annual interest rate and the term. Choose years or months to match how the loan is quoted.

2

Read the schedule

See the monthly payment, total interest and payoff time, then scan the table — yearly for the overview, monthly for detail.

3

Try an extra payment

Add an extra amount per month and watch the payoff pull forward and the total interest drop — the savings are shown for you.

Why Early Payments Are Mostly Interest

The balance is highest at the start, so the interest slice is too.

Interest each month is charged on the balance you still owe. Your fixed payment covers that interest first, and only what is left over reduces the principal. Because the balance is largest at the beginning, the interest slice starts large and the principal slice small — a loan can feel like it barely moves in its first year or two. As the principal falls, the monthly interest charge falls with it, so a steadily larger share of the same payment goes to principal, and the balance drops faster and faster toward the end.

That front-loading is exactly why extra principal early in the loan is so powerful, and why refinancing late in a term resets you back to the interest-heavy start. Switch the table above to the monthly view to watch the principal and interest columns cross over — the month where principal first exceeds interest is the turning point of the loan.

Frequently Asked Questions

What is an amortization schedule?
An amortization schedule is a table that shows, for every payment on a fixed-rate loan, how much goes to interest, how much goes to principal, and the balance left afterward. Each payment is the same total amount, but its split changes over time: early on, most of it covers interest on a large balance, and only a little reduces what you owe; as the balance falls, the interest portion shrinks and more of each payment attacks the principal, until the final payment clears it entirely. This calculator builds that full schedule for any loan amount, rate and term, and lets you view it year by year or month by month. Everything runs in your browser, so nothing you type is sent anywhere.
Why is most of my early payment interest?
Because interest is charged on the outstanding balance, and the balance is at its highest right at the start. Each month the lender charges interest on whatever you still owe; your fixed payment covers that interest first, and only the leftover reduces the principal. At the beginning the balance is large, so the interest slice is large and the principal slice is small — which is why a loan barely moves in its first year or two. As you chip the balance down, the monthly interest charge falls, so a bigger share of the same payment goes to principal, and the loan pays off faster and faster toward the end. Switch to the monthly view in this calculator to watch that crossover happen row by row.
How does an extra monthly payment save money?
Every extra dollar you pay goes straight to principal, and reducing the principal cuts the interest charged on it for every remaining month — so a small extra payment compounds into a large saving and an earlier payoff. Enter an amount in the Extra monthly payment field and the calculator rebuilds the schedule: the loan clears sooner and the total interest drops, and it shows exactly how many months and how many dollars you save versus the plain schedule. The effect is biggest early in the loan, when the balance — and therefore the interest you are avoiding — is largest. Confirm with your lender that extra payments are applied to principal and that there is no prepayment penalty.
Should I view the schedule yearly or monthly?
Use the yearly view for the big picture and the monthly view for the detail. The yearly view collapses twelve payments into one row so you can scan how the balance falls year over year without scrolling through hundreds of lines — handy for a 15- or 30-year loan. The monthly view shows every single payment with its exact principal, interest and remaining balance, which is what you want when you are checking a specific month, reconciling a statement, or watching the point where principal starts to overtake interest. Toggle between the two with the Yearly / Monthly switch above the table; both are built from the same underlying schedule.
Does this show my payoff date?
The calculator shows the payoff time — how long until the balance reaches zero — expressed in years and months, and it updates the moment you add an extra payment so you can see the loan clearing sooner. For a standard loan with no extra payments, the payoff time simply equals the term you entered; the value becomes more interesting once you add extra principal, because the loan then clears before the scheduled end. To turn the payoff time into a calendar date, count that many months forward from your first payment. The calculator works in whole months, which matches how nearly all fixed-rate loans are scheduled.
Can I use this for a mortgage, car or student loan?
Yes — the amortization math is identical for any fixed-rate, fixed-term installment loan, so this calculator works for a mortgage, an auto loan, a personal loan or a student loan. Enter the amount borrowed, the annual interest rate and the term in months or years, and you get the same accurate schedule regardless of loan type. For a mortgage where you also want property tax and insurance folded into the monthly payment, use the Mortgage Calculator instead; for building an auto loan's financed amount from price, trade-in and tax, use the Auto Loan Calculator. This page focuses purely on the amortization schedule and the payoff, which is what you want when the amount borrowed is already known.
What is the difference between amortization and simple interest?
Amortization spreads a loan across equal payments that each cover the interest accrued that period plus a slice of principal, so the balance — and the interest charged on it — falls over time. Simple interest, by contrast, charges a flat percentage of the original principal for the whole term without reducing the balance as you go, which is why it is used for short-term or interest-only arrangements rather than installment loans. Almost every mortgage, car loan and personal loan you will encounter is amortized, which is what this calculator models: the interest recalculates on the shrinking balance every month. If you need the flat-rate version instead, a simple-interest calculation multiplies principal by rate by time in one step.

More finance calculators