*Front & Back Ratio - (Likely mortgage broker limits) the front-end DTI ratio is usually calculated as housing expenses (such as mortgage payments, mortgage insurance, etc.) divided by gross income. In contrast, a back-end DTI calculates the percentage of gross income going toward other types of debt like credit cards or car loans. Lenders typically say the ideal front-end ratio should be no more than 28 percent, and the back ratio, including all expenses, should be 36 percent or lower. In reality, depending on credit score, savings and down payment, lenders accept higher ratios.