Debt to Income Ratio Calculator
Calculate your debt-to-income ratio to assess loan affordability.
What this calculator does
This debt-to-income calculator produces the two ratios lenders use to decide whether you can afford to borrow. Enter your gross monthly income, your monthly housing cost, and your total monthly debt payments, and it returns your front-end ratio, your back-end ratio, and how much additional monthly debt you could take on before crossing standard limits.
DTI is the single most decisive number in mortgage underwriting, ahead of credit score in many cases. A strong credit history tells a lender you have repaid debt before. DTI tells them whether your income can physically support the payments you are asking to add, and no amount of good history overcomes a ratio that does not work.
When to use it
Check it months before a mortgage application, not days before. DTI is one of the few underwriting inputs you can materially change on a deliberate timeline: paying off a car loan with eight payments left, or clearing a store card, removes its full monthly payment from the calculation immediately.
It is also the right tool before taking on any new obligation. Financing a car changes your borrowing capacity for a house, and the calculator makes that trade explicit — a $600 car payment on a $7,500 monthly income consumes eight percentage points of DTI, which can be $80,000 or more of mortgage capacity. Run it before signing, when the choice is still open.
Understanding the inputs
Gross monthly income is pre-tax and includes salary, reliable bonus and commission averaged over two years, and documented rental or investment income. Do not include income you cannot evidence.
Monthly housing cost is the full PITI figure — principal, interest, property taxes, homeowners insurance, HOA dues, and mortgage insurance — not just the loan payment. Total monthly debt should include that housing cost plus every other recurring debt payment: auto loans, student loans even if deferred, minimum credit card payments, personal loans, and alimony or child support. Exclude utilities, insurance, and living costs, which lenders assess separately.
How is this calculated?
DTI Ratio = (Monthly Debt Payments / Monthly Gross Income) × 100
A worked example
Take $7,500 in gross monthly income with $2,000 of housing cost. That gives a front-end ratio of 26.7 percent, comfortably inside the traditional 28 percent guideline. Now add a $525 car payment, $300 in student loans, and $150 of credit card minimums, for $2,975 of total monthly debt — a back-end ratio of 39.7 percent.
That fails the classic 36 percent test by $275 a month, though it sits inside the 43 percent qualified mortgage ceiling of $3,225. Clearing the credit cards and the car loan would drop the back-end ratio to 30.7 percent and free roughly $675 a month, which at typical rates supports well over $100,000 of additional mortgage.
Limitations and assumptions
DTI measures payment obligations against gross income and nothing else. It ignores taxes, cost of living in your area, childcare, medical expenses, savings goals, and job stability — all of which determine whether a payment is genuinely affordable. Two borrowers with identical 40 percent ratios can be in completely different financial positions.
The calculator also applies generic thresholds. Actual limits vary by loan program, by lender overlay, and by automated underwriting outcome, and compensating factors regularly move them. Use this to know where you stand and what to fix; use a lender preapproval to know what you will actually be offered.
Common Questions
- What DTI do mortgage lenders accept?
- The qualified mortgage rule generally caps back-end DTI at 43 percent, though loans sold to Fannie Mae or Freddie Mac can reach 45 to 50 percent with compensating factors such as reserves or a high credit score. FHA is more permissive, commonly allowing 31 percent front-end and 43 percent back-end, and higher with automated underwriting approval.
- What is the difference between front-end and back-end DTI?
- Front-end counts housing costs only — principal, interest, taxes, insurance, and any HOA dues. Back-end adds every other monthly debt payment: car loans, student loans, minimum credit card payments, personal loans, and court-ordered obligations like alimony or child support. Lenders look at both, but back-end is the number that usually decides approval.
- Which debts count toward DTI and which do not?
- Recurring debt obligations count. Utilities, groceries, insurance premiums other than housing-related, phone bills, and streaming subscriptions do not, even though they consume income. A debt with fewer than ten remaining payments is often excluded by underwriters, which is why clearing the tail end of a car loan can be worth more than the payment suggests.
- Does DTI use gross or net income?
- Gross — your income before taxes and deductions. That is why a DTI of 36 percent feels tighter in practice than it sounds: after federal and state tax, FICA, and retirement contributions, 36 percent of gross can easily represent half of what actually reaches your account.
- How do I lower my DTI quickly?
- Paying off a small loan entirely beats paying down a large one, because DTI counts the monthly payment rather than the balance. Eliminating a $400 car payment cuts DTI more than putting $10,000 against a mortgage. Refinancing to a longer term also works, at the cost of more total interest.
- Does DTI affect my credit score?
- No. FICO scores do not incorporate income at all, since credit bureaus do not hold it. DTI is an affordability test lenders apply separately during underwriting. A borrower can have an 800 score and be declined on DTI, and the two measures failing for different reasons is common.
- How is income counted if I am self-employed?
- Usually as a two-year average of net income from your tax returns, after business deductions. That is a meaningful problem for self-employed borrowers, since aggressive deduction of expenses reduces taxable income and therefore the income a lender will recognize. Plan two years ahead of a mortgage application if you intend to buy.
- What if my DTI is above the limit?
- The practical options are raising income, retiring a debt with a large monthly payment, buying a cheaper home, increasing the down payment to lower the housing cost, or adding a co-borrower whose income helps. Compensating factors — substantial reserves, a high credit score, a small payment increase over your current rent — can also persuade an underwriter.
Related calculators
- Home Affordability CalculatorWork backward from your income and existing debts to the maximum home price and monthly payment you can realistically carry.
- Debt Consolidation CalculatorSee how much you save by consolidating multiple debts into a single loan.
- Credit Utilization CalculatorCalculate your credit utilization ratio and its impact on your credit score.