This interest-only mortgage calculator can help you calculate your  monthly interest payment on an interest-only mortgage loan, given the amount of loan principal, annual interest rate, and the length of loan in years.

The principal on an interest-only mortgage loan will not be amortized over the life of the loan, so the borrower only pays the interest on the loan each month. The borrower is required to pay off the entire amount of the loan at the end of the loan term. Since the borrower only pays the interest on the loan, the monthly payment is relatively low compared to the monthly payment on a fully-amortized mortgage loan of the same-size, because the monthly payment on a fully-amortized mortgage loan not only includes the interest payment, but also includes a portion of principal repayment. On the other hand, since the principal has never been paid down on an interest-only mortgage loan, the borrower pays the interest accrued from the entire loan each and every month. The total interest the borrower pays over the life of the loan is much higher than that on a fully-amortized mortgage loan of the same-size.

The monthly payment on $200,000, 5.25%, 15-year interest-only mortgage loan is $875, which is much lower than that ($1607.76) on a fully-amortized mortgage loan of the same size ($200,000, 5.25%, 15-year). However, the total interest ($157,500) paid on this interest-only mortgage loan is much higher than that ($89,395.98) on a conventional fully-amortized mortgage loan of the same size. This interest-only mortgage payment calculator is designed to help you make a quick and easy calculation on your monthly payment on an interest-only mortgage loan.