What is the main function of a debt-to-income (DTI) ratio?

The main function of a debt-to-income (DTI) ratio is to evaluate the borrower's repayment ability. The DTI ratio is a critical metric used by lenders to assess how much of a borrower's gross monthly income goes toward servicing debt, including both their existing debts and the proposed mortgage payments. By quantifying this relationship, lenders can determine whether a borrower is likely to be able to manage their debt payments alongside their other financial obligations.

A lower DTI ratio indicates a greater ability to manage debt, as it shows that a smaller portion of income is consumed by debt payments, leaving more available for living expenses and savings. Conversely, a higher DTI ratio might suggest potential difficulties in meeting debt obligations, making it a crucial factor in credit assessment.

The other options might touch on broader financial analysis concepts but do not relate directly to the primary purpose of the DTI ratio. Assessing market conditions or calculating total loan amounts are not functions of the DTI ratio, nor is determining property appreciation, which deals more with the value of real estate rather than the borrower's financial profile.