A set of ratios that are used by lenders to approve borrowers for a mortgage. The borrower's front-end ratio, which is the total housing expense compared to the borrower's gross monthly income, is compared to the borrower's back-end ratio, which comprises of the total housing expense and other consumer debt compared to the borrower's gross monthly income. The front-end ratio is generally limited to a maximum of 28% and the back-end ratio is generally limited to 35%. However, both ratios change with market conditions and may be influenced by other risk factors (such as the loan-to-value ratio of the mortgage).
Qualifying ratios can vary from lender to lender, from loan program to loan program or from changing market conditions. If one or both of the qualifying ratios exceed the maximum, loan underwriters might look for "compensating factors" such as a high FICO score and/or a low loan-to-value ratio to offset the risk of high qualifying ratios in order to approve and underwrite a mortgage.