Interest only loans allow you to buy a more expensive house then you would normally qualify for. You pay only the interest of the loan for a specified period (usually up to 10 years). For example: if you apply for a 30 year loan and make 10 years of interest only payments, your loan would then revert original type of loan amortized over 20 years. This flexible calculator will calculate your payment, interest rate or loan amount based on 2 of the 3 figures given.