The deductions depend upon the type of debt you have. For example, suppose your mortgages are being used for building purposes or improvement in your primary or secondary homes. In that case, you can deduct all the additional interest you have paid for the loan. If you paid 4% interest on mortgages that cost $1 million in the home acquisition debt, you could deduct $40,000 of interest from your annual payments. However, there is a restriction in home acquisition debt if your mortgages cost $2 million. In that case, you can only deduct $40,000 instead of $80,000.