When you apply for a mortgage, one way your lender will assess your financial capacity to afford your loan is to calculate your debt-to-income ratio (DTI). Your DTI ratio compares your total gross monthly income to your total monthly debt payments. Different mortgage lenders and loan programs have varying DTI ratio requirements. Learn more: How much house can you afford? Use our home affordability calculator. What is debt-to-income ratio? The term "DTI" can be confusing because most borrowers have two ...