When you're ready to buy a new primary residence but still own your current home, you face a qualification puzzle: underwriters see two mortgages but only one income stream. Cross-qualification solves this by treating your existing home as an investment property and using its rental income to offset the old mortgage payment in your debt-to-income ratio.
How lenders count rental income
Most loan programs allow you to use rental income from your current residence when purchasing a new primary home, but they discount the figure. The standard rule: lenders credit 75% of the gross monthly rent. If market rent is $2,400, underwriting adds $1,800 to your qualifying income. The 25% haircut accounts for vacancy, maintenance, and management costs. If your old mortgage payment is $1,600, that $1,800 offsets it entirely and you carry no net housing debt from the prior home in your DTI calculation.
Lease-in-hand versus market-rent projection
Whether you need an actual signed lease depends on loan type and occupancy timing. Conventional loans often accept a market-rent analysis if you're moving more than 100 miles for work relocation or if the new home has more bedrooms than the old one—documented life-change events. FHA and VA typically require either a signed lease with at least one year remaining or a fully executed sales contract showing the old home under contract before they'll count rental income. When a lease isn't required, underwriters order an appraisal Form 1007—a single-family comparable rent schedule—that surveys similar properties and establishes fair market rent. That figure, multiplied by 75%, becomes your qualifying income.
Timing and documentation
If you already have a tenant in place, provide the signed lease, the tenant's first payment confirmation, and two years of Schedule E from your tax returns if you've been a landlord before. First-time landlords without a rental history can still qualify using the lease and Form 1007. If you're using a projection without a lease, expect underwriting to require a departure narrative—employer transfer letter, purchase contract on a larger home, or other evidence you're genuinely moving and intend to rent the old property rather than carry two primary residences. Close coordination matters: some borrowers list the old home for rent during the purchase process and bring a lease to the closing table, converting contingency approval into clear-to-close in one step.
The Alliance take
Cross-qualification turns an obstacle into an asset, but the rules are program-specific and lender overlays vary. If your current home has strong rental demand and low mortgage debt, you may qualify for a larger purchase than you expect. If equity is thin or the market soft, selling may be the cleaner path. Either way, run the numbers early—DTI, cash reserves, and rent coverage—before you commit to a purchase contract. Start an application to model your scenario with current program guidelines and see which structure works.
Rates illustrative and subject to change; may not be available at commitment or closing; not a commitment to lend.
Consult a CPA or attorney; this is not tax or legal advice.