To calculate your DTI for a mortgage, add up your monthly debt payments, divide the total by your gross monthly income, and multiply by 100. Lenders run that math two ways: once with just the proposed housing payment, and once with the housing payment plus every other recurring debt. The second number is the one that usually decides whether you qualify, and most programs want it at or below somewhere between 36 and 50 percent.
The Two Ratios Lenders Calculate
Every mortgage underwriter looks at two versions of your debt-to-income ratio. Both use the same gross monthly income on the bottom; what changes is which debts go on top.
Front-End Ratio: Housing Only
The front-end ratio is your proposed monthly housing cost divided by gross monthly income. The housing cost is the full PITI payment plus any extras:
- Principal and interest on the mortgage
- Property taxes (annual bill divided by twelve)
- Homeowners insurance (annual premium divided by twelve)
- Mortgage insurance, if required: PMI on a conventional loan with less than 20 percent down, or MIP on an FHA loan
- HOA dues, if the property has them
If that total comes to $1,800 a month and you earn $6,000 a month gross, your front-end ratio is 30 percent.1Fannie Mae. Monthly Housing Expense for the Subject Property
Back-End Ratio: Housing Plus Everything Else
The back-end ratio adds the housing payment to your other monthly debts and divides by the same gross income. Keep the example going: $1,800 housing plus $700 in auto, student loan, and credit card minimums equals $2,500. Against $6,000 of income, that’s about 42 percent. This is the figure Fannie Mae and most other investors treat as the binding limit.2Fannie Mae. Debt-to-Income Ratios
What Counts as Gross Monthly Income
Gross monthly income is what you earn before taxes and payroll deductions. For a salary, divide the annual figure by twelve. For hourly work on a steady schedule, multiply the rate by typical weekly hours, then by 52, then divide by twelve.
Overtime, bonuses, and commissions can be added, but only with history behind them. Fannie Mae looks for about two years of variable income, though twelve to twenty-four months may be enough if other factors support the shorter record.3Fannie Mae. Base Pay (Salary or Hourly), Bonus, and Overtime Income
Social Security, pensions, disability payments, and alimony or child support count too. Income with an end date, like alimony or child support, has to be scheduled to continue at least three years from the mortgage date to be included. Pension and Social Security income are generally treated as ongoing.4Fannie Mae. General Income Information
Grossing Up Nontaxable Income
Nontaxable income, such as certain Social Security or disability benefits, can be increased by up to 25 percent to reflect its purchasing power against taxable earnings. A $2,000 monthly nontaxable disability check can be counted as $2,500. For Social Security, 15 percent is automatically treated as nontaxable; grossing up more than that requires documentation that the additional portion is also tax-free.5Fannie Mae. FAQ: Top Trending Selling FAQs
Self-Employment Income
If you own 25 percent or more of a business, lenders average your net income from the past one to two years of federal tax returns. Because returns are usually optimized for low taxable income, non-cash deductions like depreciation and amortization are added back, which often raises the qualifying figure above what the return shows.4Fannie Mae. General Income Information
Rental Income
Rental income is discounted. Fannie Mae counts 75 percent of gross monthly rent and treats the other 25 percent as a reserve for vacancy and upkeep. A $2,000 rent check contributes $1,500 to qualifying income.6Fannie Mae. Rental Income
Which Debts Count, and Which Don’t
The debt side of the ratio is narrower than most people assume. Lenders pull a merged credit report from the three national bureaus and include recurring obligations that appear there or are legally required:
- Auto loans, student loans, and personal loans at their scheduled monthly payment
- Credit card minimum payments listed on your statement, not total balances
- Court-ordered child support and alimony
- Other installment debts with a fixed schedule, including medical payment plans that show on your credit report
Everyday living costs are left out even though they feel fixed: utilities, groceries, cell phone, car insurance, health insurance premiums, and streaming subscriptions do not go into DTI. The assumption is that whatever income remains after debt service covers them.
How Student Loans Are Treated
Student loans get handled differently depending on the loan program, and the gap is big enough to change whether you qualify.
On a Fannie Mae conventional loan, if you’re on an income-driven repayment plan and your documented payment is $0, the lender can qualify you using $0. You just need paperwork from the servicer showing that payment amount.7Fannie Mae. Monthly Debt Obligations
FHA is harder. Even with a $0 income-driven payment, FHA guidelines make the lender assume a monthly payment of 0.5 percent of the outstanding balance. On $60,000 in student loans, that’s $300 a month added to your DTI no matter what you actually pay. Borrowers with large balances and low IDR payments often qualify for conventional financing when FHA won’t work.
DTI Limits by Loan Program
The ceiling that applies to you depends on which mortgage you’re pursuing.
Conventional (Fannie Mae and Freddie Mac)
For manually underwritten conventional loans, Fannie Mae caps the back-end DTI at 36 percent, stretching to 45 percent when the borrower meets higher credit score and cash reserve requirements in the eligibility matrix. Loans run through the automated Desktop Underwriter system can go up to 50 percent, though reaching that level usually requires strong credit and significant savings.2Fannie Mae. Debt-to-Income Ratios
FHA
FHA generally allows a back-end DTI of up to 43 percent. With compensating factors like strong credit, extra income sources, or substantial savings, borrowers can reach as high as 50 percent when the file is approved through FHA’s TOTAL Mortgage Scorecard.
VA
VA loans have no hard cap, but 41 percent is the benchmark. Above that, lenders apply closer scrutiny to residual income, which is the cash left after the mortgage, taxes, insurance, and other debts are paid. Minimum residual income thresholds vary by region, family size, and loan amount; above 41 percent DTI, you generally need at least 20 percent more residual income than the standard minimum for your category.
USDA
USDA guaranteed rural housing loans look for a front-end ratio of 29 percent or lower and a back-end ratio of 41 percent or lower. Strong compensating factors can push the back-end limit to roughly 44 percent.
Jumbo
Jumbo loans sit above the Fannie Mae and Freddie Mac conforming loan limits, so each lender writes its own rules. Many cap the back-end ratio at 43 percent and prefer to see it below 36. Higher credit scores, larger down payments, and significant reserves are usually required alongside.
Bringing Your DTI Down Before You Apply
If the math puts you over the limit for the program you want, you have several ways to move the number before a lender locks it in.
Knock out high-payment debts. Removing a monthly payment removes it from the ratio entirely. Target debts with the biggest payment relative to the remaining balance: a car loan with a $350 payment and $2,000 left frees up more DTI per dollar than chipping away at a large student loan. Fannie Mae also lets you exclude installment debts with ten or fewer payments remaining, so you don’t always have to pay a loan off in full.8Fannie Mae. Debts Paid Off At or Prior to Closing
Zero out credit cards. Paying a revolving balance to zero at or before closing takes the minimum payment out of your DTI. You don’t need to close the account.8Fannie Mae. Debts Paid Off At or Prior to Closing
Document more income. If you’ve been earning overtime, bonuses, or commissions consistently, make sure you have at least twelve months of records so the lender can count them.3Fannie Mae. Base Pay (Salary or Hourly), Bonus, and Overtime Income Adding a co-borrower with qualifying income does the same thing by raising the denominator.
Look at a less expensive home or a longer term. A smaller loan or a 30-year term in place of a 15 produces a lower monthly payment, which pulls both ratios down. The longer term costs more interest over the life of the loan, but it may be what gets you under the threshold.
Don’t open new credit. A new card, a financed furniture purchase, or a car loan between pre-approval and closing adds to monthly obligations and can push you over the line. Lenders re-pull credit shortly before closing and will see it.