Calculate housing and total DTI, understand what debts count, and learn why lender limits vary.
Housing ratio
Debt-to-income ratio compares qualifying monthly obligations with qualifying gross monthly income. It is an underwriting measure, not a complete measure of financial comfort.
Total ratio
The housing ratio generally focuses on the proposed housing payment. The total ratio adds recurring debts such as installment loans, revolving minimums, support obligations, and other required payments.
Which debts count
Not every recurring household expense appears in DTI. Utilities, groceries, childcare, transportation, maintenance, subscriptions, and many insurance costs may be absent.
Gross income versus spendable income
Mortgage qualification commonly uses gross income before taxes and payroll deductions. Your actual spendable income can be much lower.
DTI is not a budget
A loan can meet a guideline and still feel expensive. Build a personal budget alongside the underwriting calculation and preserve room for savings and unexpected expenses.
Questions to ask before acting
- What assumptions could materially change the result?
- How much cash will remain after closing?
- What happens if taxes, insurance, repairs, or income change?
- Which terms should be confirmed in writing?
Bottom line
Use this guide as a framework for better questions and more complete comparisons. Actual eligibility, pricing, legal rights, and transaction requirements depend on the borrower, property, lender, program, contract, and location.