The percentage of a person’s monthly earnings used to pay off all debt obligations. Lenders consider two ratios, constructed in slightly different ways. The first, called the front-end ratio, the ratio of the monthly housing expenses – including principal, interest property taxes and insurance (PITY) is compared to the borrower’s gross, pretax monthly income. In the back-end ratio, a borrower’s other debts, such as auto loans and credit cards, are also figured in. Lenders usually take both into account and set an acceptable ratio, which might be expressed as 33/39. Some lenders, and some lending qualifying agencies such as FHA, take only the back-end ratio into account.