What Is a Debt-to-Income Ratio?
David and Emma are a couple in Atlanta applying for a mortgage. Together they earn $7,200 per month before taxes. Their monthly debts include a $1,600 rent payment, a $400 car loan, $150 in credit card minimums, and $250 in student loan payments. Their total monthly debt is $2,400. Their debt-to-income ratio is $2,400 divided by $7,200, which equals 33.3%. That is below the 36% threshold most lenders use, so they are in good shape. But if they take on a $300 monthly personal loan, their DTI jumps to 37.5%, which could jeopardize their mortgage approval.
Debt-to-income ratio (DTI) is the percentage of your gross monthly income that goes toward paying debts. Lenders use it to assess your ability to manage monthly payments and repay borrowed money. A lower DTI means you have more room in your budget and are a lower-risk borrower. DTI is one of the key metrics mortgage lenders evaluate alongside credit score and down payment. For a more detailed DTI tool with custom debt items, see our Debt-to-Income Ratio Calculator.
What This Calculator Does
This DTI calculator takes your itemized monthly debt payments (rent or mortgage, credit card minimums, auto loan, and other debts) and your gross monthly income, then computes your front-end ratio, back-end ratio, and an overall lender rating.
- Inputs: Rent/mortgage, credit card minimums, auto loan, other debts, and gross monthly income
- Outputs: Front-end ratio, back-end ratio, DTI rating, and a summary breakdown
How the Calculation Works
Front-End Ratio = (Housing Payment / Gross Income) x 100
Back-End Ratio = (Total Monthly Debts / Gross Income) x 100
The front-end ratio (also called the housing ratio) measures only your housing costs against your income. The back-end ratio includes all monthly debt obligations. Most conventional mortgage lenders prefer a front-end ratio below 28% and a back-end ratio below 36%. FHA loans may allow back-end ratios up to 43%, and some lenders may go higher with compensating factors.
How to Use the Calculator
- Enter your monthly rent or mortgage payment
- Enter your total credit card minimum monthly payments
- Enter your monthly auto loan payment
- Enter any other monthly debt payments (student loans, personal loans, child support)
- Enter your gross monthly income (before taxes)
- Review your DTI ratio, front-end and back-end ratios, and rating
Example Calculation
Example: A borrower earns $5,500 per month gross. Their debts are $1,400 rent, $80 credit card minimums, $300 auto loan, and $200 student loan. Total monthly debt is $1,980. Front-end ratio = $1,400 / $5,500 = 25.5%. Back-end ratio = $1,980 / $5,500 = 36.0%. The back-end ratio is right at the 36% threshold, which is acceptable for most conventional loans. To see how much home this income can support, use our House Affordability Calculator.
Common Mistakes to Avoid
- Using net income instead of gross: DTI is always calculated using gross (pre-tax) income, not net (take-home) pay. Using net income will overstate your DTI and may cause unnecessary concern.
- Forgetting debts that do not appear on your credit report: Child support, alimony, and some personal loans may not show on credit reports but still count toward your DTI. Include all monthly debt obligations.
- Not counting new debt before applying: If you plan to finance a car or take a personal loan before applying for a mortgage, factor that into your DTI calculation first. Even a $300 monthly payment can push you over the threshold.
Limitations of This Calculator
This calculator provides a standard DTI calculation using itemized debt categories. It does not account for lender-specific overlays, compensating factors, or non-standard income sources like bonuses or self-employment income, which may be treated differently by underwriters. For mortgage payment estimation, see our Mortgage Calculator.