To calculate your debt-to-income ratio with rental income, take the gross monthly rent, multiply it by 75 percent, and subtract the property’s full monthly housing payment (principal, interest, taxes, insurance, and any association dues). If the result is positive, add it to your gross monthly income. If it’s negative, add that loss to your monthly debts. Then divide your total monthly debts by your total monthly income. That percentage is your back-end DTI, and it’s the number mortgage underwriters care about most.
The mechanics shift a little depending on whether you already own the rental, whether you live in it, and which loan program you’re using. The core formula stays the same.
Why Lenders Count Only 75 Percent of the Rent
Fannie Mae and Freddie Mac guidelines require underwriters to multiply gross monthly rent by 75 percent before using it in any DTI math. The missing 25 percent is a built-in allowance for vacancy periods and ongoing maintenance.1Fannie Mae. Rental Income VA and FHA loans apply the same discount. It doesn’t matter whether the rent number comes from a signed lease or from an appraiser’s market-rent estimate; the 25 percent haircut applies either way.
For a single-unit investment property, the appraiser documents fair market rent on Fannie Mae Form 1007, the Single-Family Comparable Rent Schedule. Two- to four-unit properties use Form 1025.2Fannie Mae. Appraisal Report Forms and Exhibits The borrower pays for the appraisal, and the lender orders it.
Where the Rent Number Comes From
If you already own the rental and have reported it on your taxes, the lender starts with IRS Schedule E (Form 1040), which shows your rental revenue and expenses for the prior year.3Fannie Mae. Income or Loss Reported on IRS Form 1040 Schedule E Line 26 shows the net income or loss after expenses.4Internal Revenue Service. Schedule E (Form 1040) Supplemental Income and Loss
Underwriters don’t stop at Line 26. Schedule E deducts non-cash items like depreciation that didn’t actually leave your bank account, so Fannie Mae instructs lenders to add back depreciation, mortgage interest, property taxes, insurance, and homeowners’ association dues. Regular operating costs — maintenance, advertising, management fees, utilities — stay subtracted.1Fannie Mae. Rental Income Divide the annual result by 12 to get a monthly qualifying figure.
If the property is a brand-new purchase, or you’ve owned it too briefly to show on a tax return, the lender works from the signed lease plus the appraiser’s rent schedule and runs the 75 percent rule against that gross rent instead.
Positive Result Helps You, Negative Result Hurts You
The sign of the final number matters more than the size.
- A positive net rental income gets added to your gross monthly income. That raises the denominator in the DTI ratio and pulls the percentage down.
- A negative result — a monthly loss — is treated as a recurring debt. It raises the numerator and pushes DTI up.5Fannie Mae. Income from Rental Property in DU
The property’s PITIA never shows up twice. If the rental cash-flows positively, you add the surplus to income and the PITIA disappears into the calculation. If it loses money, you add the shortfall to debts and, again, the PITIA isn’t counted separately.
Example: Positive Cash Flow
You earn $6,000 per month at your day job. Your rental brings in $1,800 per month in gross rent. Apply the 75 percent factor: $1,350. The property’s PITIA is $1,100. Net rental income is $1,350 − $1,100 = $250. Qualifying income becomes $6,000 + $250 = $6,250. If your total monthly debts (including the new mortgage you’re applying for) are $2,500, your back-end DTI is $2,500 ÷ $6,250 = 40 percent.
Example: Rental Loss
Same rent and salary, but the PITIA on the rental is $1,500. Net rental income is $1,350 − $1,500 = −$150. That $150 is added to your other monthly debts. If those were $2,500, the lender now counts $2,650 against a $6,000 income. Back-end DTI: 44.2 percent.5Fannie Mae. Income from Rental Property in DU
If You Live in a Duplex, Triplex, or Fourplex
Rent from the unit you occupy doesn’t count. Only the other units qualify.1Fannie Mae. Rental Income The math also runs differently than for a pure investment property. You don’t net the rent against the PITIA. Instead, the qualifying rental income gets added to your total income, and the full PITIA on the property is counted as a debt.
How much of the rental income you can use depends on prior property management experience:
- With at least one year of documented experience, there’s no cap.
- Without documented experience, the rental income can only offset the PITIA. It can’t push your qualifying income higher.
- With no experience at all, you can’t use any rental income to qualify.1Fannie Mae. Rental Income
Renting Out Your Current Home to Buy a New One
Lenders call the home you’re leaving a “departing residence.” You can use rental income from it, but the rules are tighter than for a seasoned investment property. Fannie Mae and Freddie Mac require a fully executed lease plus an appraiser’s rent estimate. One year of documented property management experience removes the cap on how much rental income can count. Without that history, the rental income can only offset the PITIA on the departing property.
FHA adds a geographic rule. You generally need to show either that your new home is at least 100 miles from the departing residence or that you have at least 25 percent equity in the departing home, confirmed by appraisal. If you’re inside 100 miles with less than 25 percent equity, FHA won’t let you count any of the rent.
A Boundary: Roommate and Boarder Income
Rent from a roommate in your primary home generally doesn’t count toward qualifying income under Fannie Mae’s rules. Two narrow exceptions exist: a borrower with a disability may count rent from a live-in personal assistant for up to 30 percent of qualifying gross income, and Fannie Mae’s HomeReady program has its own boarder-income provisions.6Fannie Mae. Other Sources of Income Both exceptions require 12 months of documented payments from the boarder and proof of shared residency.
What Your DTI Needs to Clear
Your calculation is only useful once you know the target. Program ceilings vary:
- Conventional loans run through Fannie Mae’s Desktop Underwriter or Freddie Mac’s Loan Product Advisor allow a back-end DTI up to 50 percent. Manually underwritten conventional loans cap at 45 percent.7Fannie Mae. Debt-to-Income Ratios
- FHA uses 31 percent front-end and 43 percent back-end as the standard guideline. Strong credit or cash reserves can stretch the back-end to 50 percent.
- VA follows a 41 percent back-end guideline alongside a residual-income test that measures what cash remains after all debts and living expenses are paid.
Individual lenders can impose stricter overlays on top of these ceilings. When your ratio sits near the limit, whether your rental produces a $250 surplus or a $150 loss can be the difference between an approval and a decline.
Documents to Have Ready
Lenders won’t take your word for the rent figures. Expect to produce:
- Your most recent federal tax return with Schedule E if the property has rental history. Only properties listed on the Schedule of Real Estate Owned section of the Uniform Residential Loan Application (Form 1003) will be considered.3Fannie Mae. Income or Loss Reported on IRS Form 1040 Schedule E
- A signed lease agreement and the appraiser’s comparable rent schedule (Form 1007 or Form 1025) for new rentals or those without tax history.2Fannie Mae. Appraisal Report Forms and Exhibits
- The real-estate section of Form 1003, listing each property you own with its monthly rent and mortgage payment. The lender uses this section to compute net monthly rental income.8Fannie Mae. Instructions for Completing the Uniform Residential Loan Application
Don’t Pad the Numbers
Inflating rent or fabricating a lease to clear a DTI threshold is mortgage fraud. Federal law punishes knowingly making a false statement to influence a mortgage lender with up to 30 years in prison and fines up to $1,000,000.9Office of the Law Revision Counsel. 18 U.S. Code 1014 – Loan and Credit Applications Generally Even an honest misstatement can trigger a denial or force the lender to repurchase the loan from the secondary market. Build the calculation from the actual lease, the actual tax return, and the actual appraisal, and the ratio will hold up.