What is debt-to-income ratio (DTI)?

DTI is the percentage of your gross monthly income that goes toward paying monthly debt obligations. It is the single most important metric mortgage lenders use after credit score. There are two flavors: front-end DTI counts only the housing payment (PITI), and back-end DTI counts all monthly debt — housing, car loans, student loans, credit card minimums, child support, and any other recurring debt payment that shows up on your credit report.

What is a good debt-to-income ratio for a mortgage?

Below 36% back-end DTI is the classic 'comfortable' threshold. Conventional loans typically cap at 43% (sometimes 45% with strong compensating factors). FHA loans go up to 50% with strong credit and reserves. VA loans use a different residual-income method but informally target 41%. The lower your DTI, the better the rate you will be offered — borrowers under 36% routinely see 0.125–0.25% better pricing than borrowers at 43%.

How do I calculate my DTI ratio?

Add up all monthly debt payments — housing (or proposed housing for a new mortgage), car loans, student loans, credit card minimum payments (not balances), personal loans, child support, alimony. Divide by gross monthly income (before taxes). Multiply by 100 for the percentage. Example: $2,400 housing + $400 car + $300 student loan = $3,100 in monthly debt. Gross monthly income $9,000. DTI = 3,100 / 9,000 = 0.344 = 34.4%.

What is the difference between front-end and back-end DTI?

Front-end DTI includes only the housing payment (principal, interest, taxes, insurance, HOA, and PMI if applicable) divided by gross income. Lenders want this under 28% as a rule of thumb. Back-end DTI adds every other recurring debt to the housing payment before dividing. Lenders care more about back-end because it captures total debt burden; conventional loans cap at 43% back-end. Some loan programs only check back-end and ignore front-end entirely.

How can I lower my DTI before applying for a mortgage?

Three high-leverage moves. First, pay off the credit card with the highest minimum payment, not the highest balance — minimum payment is what counts in DTI. Second, pay off any car loan or installment loan with fewer than 10 monthly payments remaining; conventional underwriting allows lenders to exclude debts with 10 or fewer payments left. Third, do not open new credit accounts in the 90 days before applying — every new account adds a minimum payment to your DTI calculation. Increasing income (raise, second job documented for two years) is also effective but usually slower.

How much income do I need to qualify for a $400,000 mortgage?

Working backwards from a 36% back-end DTI cap: a $400,000 30-year mortgage at 6.5% has monthly P&I of $2,528, plus roughly 25-35% on top for taxes, insurance, and PMI — call it $3,200 in PITI. Add typical other debts of $400-$600 (car, student loans, credit cards) and you get $3,700 in total monthly debt. To stay at 36% DTI you need $10,300 in gross monthly income — about $124,000 annually. At a more aggressive 43% DTI cap, you can qualify with about $103,000. Different debt loads and rates shift these numbers, so run yours through the formula.

Does DTI include your spouse's debts?

Only if your spouse is on the loan. Mortgage lenders calculate DTI on the borrowers listed on the application, not on the household. If you apply jointly, both incomes and both debts count. If you apply solo, your spouse's debts do not appear in your DTI — but their income does not either. In community-property states (Arizona, California, Idaho, Louisiana, Nevada, New Mexico, Texas, Washington, Wisconsin), some FHA and VA lenders will pull a non-borrowing spouse's credit and count their debts even if they are not on the loan; this is a quirk worth asking about upfront.

Home › Articles › How to Calculate DTI

How to Calculate Debt-to-Income Ratio (DTI): The Number Lenders Care About Most

Your credit score gets you a quote. Your debt-to-income ratio decides whether the loan actually closes. DTI is the single number that captures whether you can afford to pay the mortgage you're asking for — and lenders use it as a hard ceiling, not a guideline. Get it under 36% and you'll see the best rates available to your credit profile. Push it past 43% on a conventional loan and the file gets denied, regardless of how good your credit is. Here's the math, the thresholds, and the levers that actually move the number.

Last updated: May 19, 2026.

The two formulas (and why both matter)

There are two DTI ratios, and lenders look at both. They measure different things and have different ceilings.

Front-end DTI is just the housing payment divided by gross monthly income:

Front-end DTI = (PITI) ÷ (gross monthly income)

PITI is principal, interest, taxes, and insurance — the full housing payment, including HOA dues and PMI if applicable. The classic lender rule is that front-end DTI should not exceed 28%. This is the "housing affordability" check.

Back-end DTI adds every other monthly debt obligation before dividing:

Back-end DTI = (PITI + all other monthly debt) ÷ (gross monthly income)

"All other monthly debt" means anything that shows up on your credit report or that the lender can document: car loan, student loan (even if currently in deferment, lenders use the projected payment), credit card minimum payments, personal loans, alimony, child support, co-signed loans you're legally on the hook for. The cap is typically 43% for conventional, higher for FHA and VA.

Why both? Front-end protects against being house-poor — having so much income going to housing that even small life events create a default risk. Back-end protects against total debt overload regardless of how much is housing. A borrower with a manageable mortgage and a $1,200/month car payment is still a credit risk; back-end DTI catches that.

A worked example

Meet a borrower applying for a $400,000 mortgage at 6.5% over 30 years. Their financial picture:

Gross monthly income (combined household): $9,000 ($108,000 annually)
Proposed PITI on the new mortgage: $3,200 (P&I of $2,528 + $500 taxes + $150 insurance + $22 PMI)
Car loan payment: $400
Student loan payment: $300
Credit card minimums (not balances): $80

Front-end DTI: $3,200 ÷ $9,000 = 35.6%

Back-end DTI: ($3,200 + $400 + $300 + $80) ÷ $9,000 = $3,980 ÷ $9,000 = 44.2%

This borrower has a problem. The front-end is past the comfortable 28% target by a wide margin, and the back-end at 44.2% exceeds the standard conventional cap of 43%. A conventional lender would either deny the file outright or require compensating factors — six months of cash reserves, a credit score over 740, a larger down payment — to push it through.

Same borrower, FHA loan: 44.2% is well within FHA's 50% ceiling. They'd get approved, but at slightly worse pricing than someone at 36%.

The fix here isn't getting a better rate. The fix is lowering DTI before applying. More on that in a minute.

The lender thresholds, by loan program

Each loan program has its own DTI ceilings. The numbers below are the standard ones; individual lenders sometimes go tighter (overlays) or looser (manual underwrites) but these are the published guidelines:

Conventional (Fannie Mae / Freddie Mac): Back-end cap of 43% on automated underwriting (DU/LP). Up to 45% with compensating factors (high credit score, large reserves, minimal LTV). Front-end is uncapped on most files but lenders watch it informally.
FHA: Back-end cap of 43% standard, up to 50% with compensating factors. Front-end target of 31% but flexible. FHA is the most forgiving of the major programs on DTI.
VA: No hard back-end cap, but VA uses a residual-income test instead — they want a specific dollar amount left over each month after all debts are paid, which varies by family size and region. Informally most VA underwriters target 41% back-end as a sanity check.
USDA (rural): Back-end cap of 41%, no exceptions on automated underwriting. Tightest of the four.
Jumbo (loans over conforming limits): Lender-set, typically 40-43% back-end. Jumbo lenders price aggressively and want squeaky-clean files; they will reject DTIs the conventional automated systems would approve.

The 43% conventional cap was effectively codified by the Consumer Financial Protection Bureau's Qualified Mortgage rule starting in 2014, which gave lenders legal safe-harbor protection for loans under that threshold. The CFPB has since updated the QM definition to use a price-based standard rather than a hard DTI cap, but the 43% number stuck in the industry as the practical default.

What counts as "debt" for DTI

Underwriters are pickier than borrowers expect about what makes the cut. The rules:

Counted in DTI:

Mortgage / housing payment (PITI)
Car loans (full monthly payment, including any lease payment)
Student loans (the higher of the actual payment or 0.5–1% of the balance, depending on program — even if currently in deferment or income-driven repayment)
Credit card minimum payments — not the balance, just the minimum that would appear on the statement. If a card has a $0 balance, it counts as $0 even though the credit limit is high.
Personal loans, signature loans
Court-ordered alimony or child support payments
Any debt you co-signed for, unless you can document twelve months of someone else paying it on time

Not counted in DTI:

Utilities (electricity, gas, water, internet, phone)
Cell phone bills, streaming services, gym memberships
Insurance premiums (health, life, auto — auto is bundled into the housing PITI for homeowners insurance only)
Childcare, groceries, gas, transportation costs
401(k) loans (you're paying yourself back; not a credit obligation)
Medical bills, unless they are in collections and being actively repaid on a payment plan

The asymmetry sometimes surprises buyers. A borrower with $2,000/month in childcare and gym memberships but no consumer debt has a strong DTI on paper, even though their actual cash flow is tight. Conversely, a borrower with low total spending but a $600 car payment has a worse DTI even if they're more financially flexible. The lender is measuring credit-risk-as-reported-on-credit-bureau, not real-world disposable income.

The three highest-leverage levers to lower DTI

If your back-end DTI is going to push you out of the loan program you want, you have three real options before applying:

1. Pay off the highest-minimum-payment credit card, not the highest-balance one. This is the most counter-intuitive move and the one most borrowers get backwards. DTI uses the minimum payment, not the balance. A $5,000 balance with a $50 minimum and a $1,000 balance with a $200 minimum hurt your DTI very differently — the $200/month card is the one that matters. Pay that one off entirely (which removes it from DTI) and your numerator drops by $200/month. On a $9,000 income, that's 2.2 percentage points of DTI shaved off in one move.

2. Pay off (or pay down) any installment loan with 10 or fewer monthly payments remaining. Both Fannie Mae and Freddie Mac guidelines explicitly allow lenders to exclude debts with 10 or fewer payments left from DTI calculations. If your car loan has 12 payments to go, pay 2 extra monthly payments and ask the underwriter to exclude it. That alone can drop DTI by 4-6 percentage points on a typical car loan.

3. Don't open new credit in the 90 days before applying. Every new credit card, store card, or financed appliance creates a new minimum payment that adds to the DTI numerator. The classic mistake is buying furniture for the new house on a 0% promotional financing offer right before closing — the minimum payment on that financing now eats into your DTI and can blow up the file. Same with leasing a new car. The rule is simple: between mortgage application and closing, change nothing about your credit profile.

Two slower options that are also effective: increase income (a raise, a documented second job — but lenders typically want two years of history on side income before counting it) and refinance high-payment debts to lower-payment versions (a 36-month auto loan at $500/month into a 60-month at $300/month — your DTI improves, even though your total interest cost goes up).

The qualifying-income inversion: how much mortgage can I afford?

Most calculators ask for a loan amount and tell you the payment. The more useful question for buyers is: given my income, what mortgage can I qualify for? That's the DTI formula run backwards.

The recipe: pick your DTI cap (36% conservative, 43% conventional, 50% FHA), multiply your gross monthly income by that cap, subtract your existing non-housing monthly debts, and the remainder is your maximum allowable PITI. Then back into a loan amount from there.

Worked example with the same borrower above ($9,000 income, $780 in non-housing debt):

At 36% conservative DTI: 0.36 × $9,000 = $3,240 maximum total debt. Subtract $780 in existing debts: $2,460 maximum PITI. Strip out roughly 25% for taxes, insurance, and PMI: about $1,968 in P&I. At 6.5% for 30 years, that's a loan of roughly $311,000.
At 43% conventional cap: 0.43 × $9,000 = $3,870. Minus $780 = $3,090 maximum PITI. P&I of about $2,472. Loan of roughly $391,000.
At 50% FHA cap: 0.50 × $9,000 = $4,500. Minus $780 = $3,720 maximum PITI. P&I of about $2,976. Loan of roughly $471,000.

The spread between conservative and aggressive is enormous — $160,000 of buying power between a 36% target and a 50% FHA ceiling, on the same income. The 50% FHA file will close, but the borrower will be living paycheck to paycheck for years and will have no margin if anything in their financial life shifts. The 36% borrower has room to breathe.

The wise number for most buyers is somewhere between 32% and 38% back-end DTI. That's room for retirement contributions, an emergency fund, and the inevitable surprise expenses of homeownership without the mortgage payment becoming the source of stress. Lenders will let you borrow more. They are not the ones making the payment.

Frequently asked questions

What is a good debt-to-income ratio?

Below 36% back-end is the classic "comfortable" threshold and what most financial planners recommend. Lenders will go higher: conventional caps at 43%, FHA at 50%, but each step up the DTI scale costs you slightly worse pricing and far less flexibility once you actually have the mortgage. Aim for 36% if you can get there; treat the higher caps as ceilings to clear, not targets to hit.

Are credit card balances or minimum payments used in DTI?

Minimum payments. The lender pulls your credit report and uses whatever minimum payment appears for each open credit card account. A $20,000 balance with a $200 minimum hurts your DTI by exactly $200/month — same as a $2,000 balance at the same minimum. This is why "pay off the highest minimum payment" beats "pay off the highest balance" as a DTI optimization strategy. The balance affects your credit utilization score, but DTI cares only about the monthly payment.

Do student loans count if I'm on income-driven repayment?

Yes, but the calculation depends on the loan program. Conventional and FHA lenders will use the actual income-driven payment if you can document it (your servicer's statement showing the current monthly amount). If the documented payment is $0 (which can happen on PAYE, REPAYE, or SAVE), Fannie Mae allows lenders to use $0 in DTI for conventional loans, but FHA requires either the actual payment OR 0.5% of the outstanding balance, whichever is greater. VA uses 5% of the balance divided by 12. So the same student loan can show up as $0 on a conventional file and $300/month on a VA file — strategy depends on which program you're applying for.

Can I include rental income or side-hustle income in DTI?

Sometimes. Rental income from an existing property typically counts at 75% of gross rents (the 25% haircut covers vacancy and maintenance), but only if you can document at least two years of rental history on tax returns. Side-hustle 1099 income generally requires two years of tax returns showing consistent earnings. W-2 wages from a second job count if you can document at least two years of consistent earnings. The two-year rule is the dominant constraint — lenders are skeptical of new income streams because they have no history to confirm sustainability.

How does DTI differ for FHA, VA, and conventional loans?

Conventional caps at 43% (sometimes 45% with compensating factors), uses automated underwriting (Desktop Underwriter from Fannie Mae or Loan Prospector from Freddie Mac), and is the strictest of the three on DTI. FHA caps at 50% with compensating factors, has a slightly more lenient student-loan calculation, and is designed to serve borrowers with weaker credit profiles. VA uses a residual-income test instead of a hard DTI cap — they want a specific dollar amount in your pocket each month after debts are paid, which varies by family size and region (the threshold is roughly $1,000 for a family of four in most areas). Informally most VA underwriters use 41% as a back-end sanity check, but a 45% file with strong residual income often clears.

What if my DTI is already over 50%?

You almost certainly cannot get a standard mortgage in that condition. The path forward is one of three options: lower the DTI before applying (the levers above — pay off high-minimum cards, eliminate near-paid-off installment loans, do not open new credit), increase income (raise, second job documented for two years, spousal income added to the application), or wait. There are non-QM lenders who will write loans at 55% DTI for borrowers with strong credit and large reserves, but pricing is materially worse — typically 1-2 percentage points higher than conventional, plus higher fees. For most buyers, the math doesn't work; better to delay six to twelve months and bring DTI under 43%.

How does DTI affect my mortgage rate?

Indirectly but real. Most lenders don't have explicit rate adjustments for DTI the way they do for credit score and loan-to-value, but DTI affects which loan programs and which lenders you qualify for. A 35% DTI borrower with a 760 credit score gets quoted by every lender at the best rate the market is offering. A 47% DTI borrower with the same credit score is locked out of most conventional lenders, must use FHA or non-QM, and typically pays 0.25-0.50% more on the rate. Over a 30-year $400,000 loan that's $20,000-$40,000 of additional interest. DTI is a price input even when it isn't a stated price input.

Try it yourself

Plug your numbers into the formula above — or just open our DTI calculator, which does both the forward (find my DTI) and reverse (max mortgage at my income) calculations live and shows you exactly where you land against the Conventional, FHA, VA, and USDA ceilings. If you're trying to figure out how much house you can afford, the reverse mode is the fastest way to back into a loan amount; the mortgage calculator then turns that into a full PITI breakdown at current rates. The number you get is the upper bound on what a lender will approve. The number you should actually borrow is usually 10-20% lower than that.