Amortization Schedule

This amortization schedule calculator shows every payment of a loan, from the first to the last. Enter the loan amount, interest rate, term and first payment date, and you get a dated table showing how much of each payment goes to interest and how much to principal, the running total of interest, and the balance left. You can pay monthly, twice a month, every two weeks or weekly, add extra payments, and download the whole schedule as a CSV file for Excel or Google Sheets.

What is an amortization schedule?

To amortize a loan means to pay it off with equal, regular payments. An amortization schedule is the table of those payments. Each row shows the payment date, the interest charged since the last payment, the part of the payment that reduces the debt (principal), and the balance remaining. Mortgages, car loans, personal loans and most student loans are all amortized loans, so the same schedule works for all of them.

How the schedule is calculated

The payment. Payment = P × r / (1 − (1 + r)^−n), where P is the loan amount, r is the interest rate per payment period and n is the number of payments. The rate per period is the yearly rate divided by the number of payments in a year: 12 for monthly, 24 for twice a month, 26 for every two weeks and 52 for weekly. For $250,000 at 6.5% over 30 years with monthly payments, the payment is $1,580.17.

Each row. Interest = balance × r. The rest of the payment is principal, and the new balance is the old balance minus the principal and any extra payment. In month 1 of the example, interest is $1,354.17 and principal only $226.00. The last payment is adjusted so the balance ends at exactly zero.

The dates. Monthly payments fall on the same day each month; if that day does not exist (such as the 31st in February), the payment moves to the last day of the month. Payments twice a month fall on the chosen day and 15 days later. Payments every two weeks or every week are exactly 14 or 7 days apart.

Reading the schedule: interest comes first

Early payments are mostly interest, because interest is charged on the full balance. In the $250,000 example, the first 5 years of payments add up to about $94,810, but only $15,972.56 of that reduces the loan; $78,837.65 is interest. After 10 years you still owe $211,940.32. The principal part of each payment only becomes larger than the interest part with payment 233, more than 19 years into the loan. This is why extra payments made early save the most.

The schedule covers principal and interest only. A mortgage payment often also includes property tax and home insurance held in an escrow account, and those are not part of the loan's amortization.

Ways to pay off a loan faster

All of these were calculated with the $250,000, 6.5%, 30-year example, which costs $318,861.22 in interest without extra payments:

• $100 extra every month: the loan ends after 304 payments (25 years and 4 months) instead of 360, and you save $58,859.89 in interest.
• One extra payment a year: paying an extra $1,580.17 every December ends the loan after 289 payments and saves $75,460.75.
• Half the payment every two weeks: paying $790.09 every two weeks means 26 half-payments, or 13 full payments, a year. The loan ends after about 24.2 years and you save $73,434.82.
• One-twelfth more each month: adding $131.68 to every monthly payment has almost the same effect, 290 payments and $72,713.23 saved, without changing your payment dates.

To model the half-payment-every-two-weeks plan here, choose Every 2 weeks and add the difference between half the monthly payment and the every-two-weeks payment as an extra with every payment. Before paying extra, check that your loan has no prepayment penalty, and ask the lender to put the extra money toward the principal.

Using the CSV download

The Download CSV button saves every payment as a row with its number, date, payment, extra payment, principal, interest, total interest and balance. Dates use the year-month-day format and amounts use a plain decimal point, so the file opens correctly in Excel, Google Sheets, Numbers or LibreOffice in any country. You can use it to track your real payments against the plan, or to compare loan offers side by side.