Amortization Calculator
Build the amortization schedule of a fixed-rate loan, with monthly payments or with half the monthly payment every two weeks. The term can be in years or in months, down to one month. Each row shows how much of the payment is interest, how much repays principal and what you still owe, in whole cents. A 0% rate works too.
How to use the Amortization Calculator
- Enter the loan amount, the annual interest rate and the term in years or months. The term has to come to whole months, so 2.5 years is 30 payments.
- Press the Calculate button. You get the monthly payment, the total interest and the total payment, with the amortization schedule below them.
- The schedule opens with the first 12 payments. The Show all button under the table adds the rest, down to a balance of $0.00.
- To try other numbers, change any value and press Calculate again.
The amortization mechanics
M = P · r(1 + r)^n / ((1 + r)^n − 1) · · · Interest_k = Balance_(k−1) · r · · · Principal_k = M − Interest_k · · · Balance_k = Balance_(k−1) − Principal_k
M is the monthly payment, P is the loan amount, r is the annual rate divided by 12 and n is the number of monthly payments. The calculator rounds M to the cent. Each month the interest is r times the balance, rounded to the cent, and the rest of the payment reduces the balance. The last payment pays off whatever is left, so the Principal column adds up to the loan amount. At 0% the payment is P divided by n.
Worked example
A $200,000 loan at 6.5% over 30 years has a monthly payment of $1,264.14. In month 1 the interest is 200,000 × 0.065 ÷ 12 = $1,083.33, so $180.81 goes to principal and the balance falls to $199,819.19. By payment 240 the interest is down to $606.59 and the principal is up to $657.55. The last of the 360 payments is $1,259.56. In total you pay $455,085.82, of which $255,085.82 is interest. Paid biweekly, half of that payment is $632.07 every two weeks. 628 payments clear the loan in about 290 months and cost $196,339.36 of interest, $58,746.46 less than monthly.
Frequently asked questions
What does the biweekly schedule do?
It pays half the monthly payment every two weeks. That is 26 half payments a year, the same as 13 monthly payments, so the loan ends sooner. Each row charges the balance one 26th of the annual rate. It takes each payment as credited on the day you pay it. A servicer that holds half payments until a whole monthly payment is in charges more interest than the schedule shows, so ask yours how it credits them. A loan set up with 26 payments a year that lasts the full term has smaller payments, and this schedule does not model it.
Can I enter a term under one year?
Yes. Choose Months and type a whole number from 1 to 1,200. $5,000 at 8% over 6 months is a monthly payment of $852.89. A term in years still works, so 0.5 years gives the same schedule.
Why is so much of my early payment interest?
The lender charges interest on the balance you still owe, and the balance is largest at the start. On a $200,000 loan at 6.5% over 30 years, $1,083.33 of the first $1,264.14 payment is interest. Of the last payment, only $6.79 is.
Can I calculate a loan at 0% interest?
Yes. Enter 0 as the rate, and the payment is the loan amount divided by the number of months, rounded to the cent. $10,000 over 3 years is 35 payments of $277.78 and a last payment of $277.70. Every interest figure is $0.00, and you pay back $10,000.00.
Why is the last payment different from the others?
The calculator rounds the payment and each month's interest to the cent. Over the term those roundings add up, and the last payment settles the difference, so the balance ends at exactly $0.00. On a $200,000 loan at 6.5% over 30 years, the first 359 payments are $1,264.14 and the last is $1,259.56.
Why does my schedule end before the term?
The calculator rounds the payment and the interest to the cent, and on a small loan over a long term that can repay the balance before the last month. $1,000 at 4.5% over 40 years has a payment of $4.50, and payment 479 of 480 clears the balance. The calculator says so above the schedule, which ends there.
Can I add extra payments?
Not on this page. The mortgage amortization calculator takes extra monthly, yearly or one-time payments and shows the months and interest they save.