How to use the amortization calculator
Enter the amount you borrowed or plan to borrow, the interest rate, the term in years and months, and the month of your first payment. The calculator shows the monthly payment, the total interest, and the date of your final payment, and lists every payment below it. Use the Show menu to switch between the month-by-month schedule and a yearly summary, and download the full schedule as a CSV file to keep or share.
To test paying the loan off early, add an extra amount every month (and the payment number it starts with) or a one-time lump sum. The results compare the faster schedule with the original one, so you see the payoff date, the interest saved and the time saved. Nothing you type leaves your device.
This page is for the detailed schedule. To solve for something else, such as how much you can borrow for a given payment or how long a payment takes to clear a loan, use the loan calculator. For a loan with an origination fee and APR, try the personal loan calculator; for a car with a down payment, trade-in and sales tax, use the auto loan calculator.
What amortization means
Amortization means paying off a loan with regular payments so that the amount you owe goes down with each one. Negative amortization is the opposite: if a payment does not cover the interest, the unpaid interest is added to the balance and you owe more (CFPB: What is negative amortization?). Every schedule on this page is fully amortizing: the fixed payment always covers the month's interest, and the balance reaches zero on the last payment.
For closed-end consumer loans, lenders must disclose the number, amounts and timing of the payments scheduled to repay the loan, and the total of payments, "the amount you will have paid when you have made all scheduled payments" (CFPB: Regulation Z §1026.18, content of loan disclosures). An amortization schedule shows how each of those payments splits between interest and principal.
How each row is calculated
The monthly payment is M = P × r ÷ (1 − (1 + r)−n), where P is the loan amount, r is the yearly rate ÷ 12 and n is the number of monthly payments. Each month, interest is the remaining balance × r. The rest of the payment, plus any extra, reduces the balance.
Take $250,000 at 6% for 30 years. The payment is $1,498.88. In month one, interest is $250,000 × 0.005 = $1,250.00, so only $248.88 goes to principal and the balance falls to $249,751.12. In month two, interest is a little lower ($1,248.76) and principal a little higher ($250.12). Like a lender's schedule, interest is rounded to the cent each month and the final payment ($1,495.45 here) pays off the exact remaining balance.
Reading the schedule: why early payments are mostly interest
Because interest is charged on what you still owe, the first years of a long loan go mostly to interest. In the first 12 payments of the example you pay $14,916.50 of interest and only $3,070.06 of principal. Principal first exceeds interest at payment 223, about 18 years 6 months in, and the balance does not drop below half the loan until payment 252. Over the full 30 years the interest adds up to $289,593.37, more than the amount borrowed.
The rate changes this a lot. The same loan costs $233,141.28 in total interest at 5% (payment $1,342.05) and $348,769.07 at 7% (payment $1,663.26). A shorter term cuts it too: over 15 years at 6% the payment rises to $2,109.64, but total interest falls to $129,735.85.
How extra payments change the schedule
Extra principal lowers the balance that every later month's interest is charged on. Adding $200 a month to the example loan from the first payment pays it off 7 years 9 months sooner and saves $86,231.98 in interest. A single $5,000 payment with payment 12 saves $22,168.13 and 1 year 6 months. Both together save $98,647.19, with the last payment in May 2048 instead of Dec 2056.
The earlier an extra payment is made, the more it saves, because it removes interest from every remaining month. Change the "payment #" fields to see how much a later start costs you.
Before you prepay, check your loan documents. Some lenders charge a prepayment penalty if you pay off all or part of a mortgage early; it typically applies only when you pay off the entire balance within a set number of years, for example because you sell or refinance, and not normally to small extra principal payments (CFPB: What is a prepayment penalty?). Ask your servicer to apply extra money to principal.
What the schedule does not include
Taxes and insurance. Many mortgage payments include an escrow amount for property taxes and insurance, which can change from year to year (CFPB: What is an escrow or impound account?). This schedule covers principal and interest only.
Fees and APR. The APR adds points, fees and other charges to the interest rate, so it is usually higher than the rate used here (CFPB: What is the difference between an interest rate and an APR?).
Rate changes. The calculator assumes a fixed rate. With an adjustable-rate mortgage, the rate resets to an index plus a margin after the initial period, so later rows would change (CFPB: ARM index and margin). To see how interest grows on savings rather than debt, try the compound interest calculator or the simple interest calculator.
Updated October 30, 2026 · Sources are linked in the text above · How we build and check our calculators