How Much Rental Income Counts When Buying a Multi-Family Property?
On paper, rent from a second unit looks like straightforward extra income, but lenders rarely take that number at face value when deciding how much someone can borrow.
The short answer
Lenders typically count only a percentage of a property’s projected rental income toward a buyer’s qualifying income, rather than the full amount. A common approach applies a standard discount, often cited around 25 percent, to an appraiser’s market rent estimate to account for vacancy, turnover, and the ongoing cost of maintaining the unit. The exact figure and the documentation required to support it depend on the specific loan program and whether the buyer already has landlord experience.
Why lenders discount projected rent
A unit that’s supposed to bring in a certain amount each month doesn’t always do so reliably — tenants move out, units sit vacant while being re-rented, and turnover brings costs like cleaning, repairs, and lost rent during the gap. Counting the full market rent as if it were certain would overstate what a property can actually be relied on to produce. The discount is a built-in cushion that reflects the real-world gap between a property’s advertised rent and the income it consistently delivers, and it factors directly into how a buyer’s debt relative to income gets calculated.
How the projected rent is determined
For a purchase, rental income usually can’t be based on the buyer’s own guess or even a signed lease with a future tenant who hasn’t moved in yet. Instead, lenders typically rely on an appraiser’s opinion of fair market rent for each unit, based on comparable rentals in the area, documented on a specific rent schedule form completed as part of the appraisal. That figure becomes the starting point before any vacancy discount is applied.
What documentation typically supports it
For a property already generating rent, such as one being purchased with existing tenants in place, lenders may also look at the seller’s actual rental history, often through tax returns or a lease, in addition to or instead of the appraiser’s estimate. Requirements vary by loan program and can also depend on whether the buyer has a track record managing rental property, since a first-time landlord and someone with years of documented rental income may be asked for different levels of documentation.
Owner-occupied vs. non-owner-occupied differences
How rental income factors into qualifying can also depend on whether the buyer plans to live in the property. For an owner-occupied multi-unit purchase, only the income from the units the buyer won’t occupy typically counts, since the unit they live in doesn’t generate rent. For a property purchased purely as an investment, with the buyer living elsewhere, a larger share of overall rental income may factor into qualifying, though those loans generally come with their own stricter down payment and reserve requirements.
Programs vary in the specifics
Rules differ somewhat across loan programs. Some, particularly FHA-insured loans on three- and four-unit properties, layer on additional requirements about how rental income relates to the property’s own mortgage payment. Others may allow a different discount percentage or different documentation standards. None of this is standardized enough to assume one figure applies universally, which is part of why it’s worth asking a lender directly how a specific property’s projected rent would be treated before assuming a particular loan amount is within reach.
The takeaway
Rental income from other units can meaningfully expand what a buyer qualifies to borrow, but it’s counted conservatively, not at face value. Understanding that a lender will likely apply a discount to projected rent — and will want documentation to support the number — helps set realistic expectations before shopping for a multi-unit property.