Buy Before You Sell: Excluding Your Old Mortgage From DTI

How the 75% rule works in practice

The challenge many repeat buyers face in a hot market is a timing problem: you've found the home you want, but your current home hasn't sold yet, so the lender counts both mortgage payments in your debt-to-income (DTI) ratio. That can push you over Fannie Mae's 45% limit and force you into a contingent offer — one that requires your old home to sell before the new deal can close — which often gets you outbid.

Fannie Mae's Selling Guide offers a way around that delay. Under the right conditions, the lender can treat your to-be-vacated home as a departing residence and exclude its payment from your DTI entirely, letting you qualify for the new loan before the old home closes. I'm Lavonte Robinson, a Loan Officer at Ruoff Mortgage (NMLS# 141868, NMLS# 1771049) in Fort Wayne, Indiana, and I'll walk you through exactly how this works.

Here's a concrete example. Say your current home's PITIA is $1,400 a month, and an appraisal shows it rents for $2,000. Fannie Mae counts 75% of that market rent — $1,500 — as qualifying rental income, then nets it against the $1,400 payment. That leaves $100 of positive rental income, which means the departing residence contributes no debt at all to your new loan. You can qualify for the new mortgage before your old home ever closes.

The flip side is worth understanding too. If the payment were $1,700 and market rent only $2,000 (75% of that is $1,500), the shortfall of $200 would be added back into your DTI as a monthly liability. In that scenario you'd carry roughly $200 a month of the old house on your ratios — still far better than the full $1,700 — but it does eat into your buying power. The closer your rent is to your payment, the cleaner the offset works.

Two other details shape the outcome. First, the lender must confirm the current housing payment on the departing residence before any rental income can be used. Second, if you have less than 12 months of property management experience, Fannie Mae requires you to verify six months of reserves to cover the vacated home's PITIA on top of any reserves needed for multiple financed properties — a real cash requirement worth planning for before you shop.

How rental income offsets the payment

What counts as a departing residence

Fannie Mae's Selling Guide treats your current home as a departing residence when you are buying or building a new principal residence that will replace it. Because the departing residence is an investment property — not the subject property of the new loan — the old mortgage payment can drop out of your DTI calculation once you rent it out, as outlined in the Selling Guide's General Rental Income Information topic.

The lender must document the current housing payment on the departing residence before any rental income counts toward qualifying, which Fannie Mae's guidelines spell out in detail.

Once your home qualifies as a departing residence, Fannie Mae lets you use the projected rental income to offset — or even cancel out — the departing payment. The key number is the 75% rule: the lender uses 75% of your appraised market rent as qualifying income, then nets it against the old PITIA (principal, interest, taxes, insurance, and any HOA dues). Fannie Mae applies this discount to cover vacancy risk and operating expenses (General Rental Income Information).

Importantly, this works whether or not you already own a rental. The bigger hurdle is your property management history. If you have less than 12 months of property management experience, Fannie Mae restricts how much of that rental income counts toward qualifying. With no prior experience, the lender may only use qualifying rental income to offset the PITIA — not to add net positive income that boosts your buying power. That's a meaningful difference: offsetting the old payment is often enough to get you qualified, while counting surplus rent to widen your loan amount needs a track record behind it.

Your lease agreement also has to meet the guidelines. For a newly executed lease dated within two months of the loan application, Fannie Mae requires a minimum six-month term with the initial rental payment due on or before the first payment due date of the new mortgage. And the lease cannot be with a family member or any interested party — Fannie Mae will not count rent paid by someone connected to the deal.

The documentation checklist

To use this strategy, your lender needs specific paperwork, and Fannie Mae requires more than a signed page. At minimum, be ready to provide:

• A fully executed lease agreement for the departing residence. For a newly executed lease dated within two months of the loan application, Fannie Mae requires a minimum six-month term, with the first rental payment due on or before the first payment due date of the new mortgage (B3-3.8-01).

• Proof the lease is not with a family member or interested party — Fannie Mae explicitly bars counting rent from one of those.

• Documentation of your current housing payment if it isn't already on the credit report — payment history, cancelled checks, or direct verification from a management company.

• Property management history. If you have less than 12 months of property management experience, Fannie Mae restricts how rental income can be used to offset the payment.

Two more details affect whether this strategy clears underwriting. First, your new loan must still meet Fannie Mae's standard debt-to-income caps for the loan program you're using — the departing-residence exclusion removes the old house from your ratios, but it doesn't relax the limits on everything else. Second, the appraisal needs to support the market rent you're claiming; if the appraisal comes in low, the income that offsets your payment drops too, and that can reopen the gap between rent and payment.

Talk to a loan officer before you sign a lease, though. Whether the departing residence only offsets its own PITIA — or contributes net positive income that helps you qualify for more — depends on your property management history and your exact situation, and the guidelines change over time. What works in your file on paper has to hold up in underwriting.

Ready to see if this fits your situation?

Every repeat buyer's file is different, and the departing-residence rules are detailed enough that a quick conversation saves time. If you're weighing buying before selling, reach out — I can help you map your numbers against the current guidelines. I'm Lavonte Robinson, Loan Officer at Ruoff Mortgage, NMLS# 1771049. Happy to answer questions.