DTI Calculator
Calculate your debt-to-income ratio to see if you qualify for a mortgage or loan. Understand your front-end and back-end DTI with lender requirements.
Reviewed by the Calcura editorial team · Last reviewed
- Question
- How do I calculate my debt-to-income (DTI) ratio?
- Answer
- DTI uses two measures. Front-end DTI = housing costs (PITI) / gross monthly income — lenders want ≤ 28%. Back-end DTI = (housing + all other recurring debt) / gross monthly income — lenders want ≤ 36% for conventional, up to 43% for FHA. If your PITI is $2,000 and gross income is $8,000/month, front-end DTI is 25%. Add $500 in car and credit-card minimums and back-end DTI is 31.25%.
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- Formula
front_end = PITI / gross_monthly; back_end = (PITI + debts) / gross_monthly- Caveats
- Use gross (pre-tax) monthly income, not take-home pay.
- Only minimum required payments count for DTI, not what you typically pay each month.
- Student loans in deferment still get counted — lenders use 0.5–1% of the balance as a minimum payment.
Monthly Income
Monthly Housing Costs
Other Monthly Debt
Include minimum payments for all recurring debt. Do not include utilities, groceries, or other living expenses.
What This Calculator Does
This calculator computes your debt-to-income ratio — the percentage of your gross monthly income committed to debt payments — and compares it against mortgage qualification thresholds. It returns both front-end DTI (housing costs only) and back-end DTI (all recurring debt), along with a read against the 28/36 conventional guideline, the 43% FHA ceiling, and VA/USDA benchmarks. Use it before applying for a mortgage so the number you submit isn't a surprise, or after a denial to see which debt is tipping you over.
When To Use This Calculator
Before Shopping for a Home
You earn $95,000 annually and want to know your budget. Current debts: $350/month car payment, $200/month student loan. Your monthly gross income is $7,917. With those existing debts, a lender using the 36% rule would cap your total monthly debt at $2,850. Subtract existing $550 in debts, and your maximum housing payment is $2,300 — including taxes and insurance.
After Getting Pre-Denied for a Mortgage
You applied and were told your DTI was too high at 47%. Calculate your exact ratio to see which debts are pushing you over. Maybe that $400/month car payment is the problem. Paying it off would drop your DTI to 42% — still tight for conventional but within FHA range. Or waiting 6 months to pay down $8,000 in credit card debt could bring it below 36%.
Deciding Whether to Take on New Debt
You're pre-approved for a mortgage and thinking about financing a new car before closing. Calculate how a $500/month car payment changes your DTI. If it pushes you from 34% to 40%, that car loan could cost you your mortgage approval or bump you into a higher interest rate tier — potentially costing tens of thousands over 30 years.
Annual Financial Health Check
DTI isn't just for mortgages. A back-end DTI above 43% means nearly half your gross income goes to debt payments, leaving little for savings or emergencies. Checking annually helps you catch debt creep — the gradual addition of payments that individually seem small but collectively squeeze your finances.
How It Works
The calculator divides your debt obligations by your gross monthly income (before taxes). Front-end DTI counts only housing costs: mortgage or rent, property taxes, homeowners insurance, and HOA fees. Back-end DTI adds all recurring debt payments on top of housing: credit card minimums, auto loans, student loans, personal loans, child support, and alimony. Gross income means your total earnings before any deductions — not your take-home pay. Lenders use gross because tax situations vary. The result is a percentage: if 35% of your gross income goes to debt, your back-end DTI is 35%. The lower the number, the more financial flexibility you have and the more favorably lenders view your application.
Formula
Front-End DTI = (Housing Costs / Gross Monthly Income) × 100
Back-End DTI = (All Monthly Debt Payments / Gross Monthly Income) × 100Real-World Example
Scenario
Marcus earns $110,000 annually and wants to buy a $380,000 home with 10% down ($342,000 mortgage). His existing debts: $380/month car loan, $250/month student loans, $120/month credit card minimums.
Calculation
Gross monthly income: $110,000 / 12 = $9,167 Proposed housing costs: Mortgage payment: $2,150 Property taxes: $380 Insurance: $140 Total housing: $2,670 Front-end DTI: $2,670 / $9,167 = 29.1% All debts: $2,670 + $380 + $250 + $120 = $3,420 Back-end DTI: $3,420 / $9,167 = 37.3%
Result
Marcus's front-end DTI of 29.1% is just above the ideal 28% threshold — acceptable for most lenders. His back-end DTI of 37.3% exceeds the conventional 36% target but is well within the FHA limit of 43%. To get the best conventional rates, he could pay off his credit cards ($120/month) to drop to 35.9%, or wait until his car loan ends. Alternatively, he could target a slightly cheaper home to bring housing costs down by $100-200/month.
Common Mistakes to Avoid
Mistake: Using net (take-home) income instead of gross income
Solution: Lenders always use gross income — your salary before taxes, retirement contributions, and health insurance deductions. Using take-home pay will make your DTI look worse than what lenders calculate. If your salary is $85,000, your gross monthly income is $7,083, not whatever your paycheck shows after deductions.
Mistake: Forgetting property taxes and insurance in housing costs
Solution: Front-end DTI includes PITI: principal, interest, taxes, and insurance. Property taxes alone can add $300-$800/month depending on location. Homeowners insurance adds another $100-$300. These are part of your DTI even though they aren't technically debt.
Mistake: Not including student loans in deferment or forbearance
Solution: Most lenders count deferred student loans at 0.5-1% of the balance as a monthly obligation, even if you're not currently paying. A $40,000 deferred student loan adds $200-$400 to your monthly debt calculation. Check with your specific lender for their policy.
Mistake: Taking on new debt between pre-approval and closing
Solution: Lenders recheck your DTI before closing. A new car loan, furniture financing, or even opening a new credit card can push your DTI above the threshold and kill an approved mortgage. Avoid any new debt from pre-approval until after you have the keys.
Related Financial Calculators
Mortgage Affordability Calculator
Works backwards from your income and DTI to calculate the maximum home price you can afford. Use DTI to know your ratio, then use Mortgage Affordability to find your price range.
Mortgage Calculator
Calculate monthly mortgage payments including taxes and insurance. Use this to get the housing cost numbers you'll plug into DTI.
Credit Card Payoff Calculator
Plan how to eliminate credit card debt — the fastest way to reduce your back-end DTI. Each card paid off directly lowers your ratio.
Income After Tax Calculator
While DTI uses gross income, knowing your after-tax income helps you budget realistically for the mortgage payment your DTI allows.
When This Isn't the Right Tool
Self-employed or variable-income borrowers
Use instead: Lenders calculate qualifying income from two years of tax returns (often an average of Schedule C net income), not your gross monthly draw. A straight annual-income entry in this calculator will usually overstate the income a lender will credit — check with a mortgage professional for the exact figure.
Gig or 1099 income under two years old
Use instead: Conventional underwriting typically excludes self-employment income that hasn't been documented for 24 months. If a large share of your income is new 1099 work, your lender-calculated DTI may look much worse than the DTI shown here.
Co-borrowers and non-occupant co-signers
Use instead: Different programs treat co-borrower income and debts differently — some blend both incomes and both debt stacks, others apply separate tests. For any co-borrower scenario, run the numbers with your lender rather than relying on a single combined entry here.
Student loans in deferment or on income-driven plans
Use instead: Lenders often use a hypothetical payment (commonly 0.5–1% of the balance) rather than your actual $0 or IDR payment. Check the exact policy for your loan program — Fannie Mae, Freddie Mac, FHA, and VA each handle deferred student loans differently.
How to Verify This Calculation
The back-end DTI here should match any lender's pre-qualification tool when you enter the same inputs (gross income, same debt list). The CFPB's homebuying guidance walks through the same 28/36 framework, and Fannie Mae's Selling Guide and HUD's FHA Handbook publish the current ceilings directly. If a lender quotes a very different DTI, the likely cause is how they treat student-loan, deferred, or self-employment income — ask them to show the line-item calculation.
Sources
- Consumer Financial Protection Bureau — Debt-to-income ratio — Plain-language explanation of how DTI is calculated and why lenders use it.
- HUD — FHA Single Family Housing Policy Handbook (4000.1) — Official FHA underwriting guidance including DTI ceilings and compensating factors.
- VA — Home loan eligibility and credit standards — VA home loan program rules, including the residual-income test used alongside DTI.
- Fannie Mae — Selling Guide — Conventional underwriting standards for DTI, income calculation, and debt treatment.
Reviewed by the Calcura editorial team · Last reviewed