Conventional Loan Requirements for Buying While Keeping Your Mortgage

The Quick Read: You can usually buy a new primary home with a conventional loan while keeping the mortgage on your current one, but the new lender has to count the old payment. What that payment does to your file depends on what the old home becomes: a rental, a second home, or a pending sale. The pressure point is your debt-to-income ratio, and sometimes your cash reserves.

What “Keeping Your Mortgage” Means Here

It means you do not pay off or refinance the loan on the home you are leaving. The old loan stays in place, and the new lender reviews your file with that payment included. Nothing about the old loan’s terms changes. What changes is how a new lender reads it.

One confusion comes up often: there is no such thing as two primary residences. The new home must be your principal residence. The old one becomes something else, and that “something else” drives everything here.

Across the wholesale programs Lendmire places files with, the first question is often not about credit or down payment. It is “what happens to the old house?” Answer that cleanly and the rest of the file tends to fall into line.

The Core Requirements, Checked Against Your Situation

Lendmire is a mortgage broker arranging conventional loan programs through wholesale lenders in 16 states. The envelope those programs work in looks like this, subject to lender guidelines and full file review.

A few notes on that table. The 97% lane requires at least one first-time buyer, meaning no ownership interest in a residence in the previous three years. A current owner generally does not qualify. The 95% lane is the realistic one. Mortgage insurance above 80% LTV can be requested for cancellation at 80% of original value with good payment history, and the servicer must end it automatically at 78%.

Manually underwritten files are tighter, at 36% or 45% total ratio depending on credit score and reserves. Most files run through automated underwriting, where the ceiling is higher. Fannie Mae’s debt-to-income rules set those three tiers: 36%, 45% and 50%.

How Lenders Count the Old Home

Fannie Mae states that the status of the existing property determines how its payment is considered in qualifying for the new loan. Three paths exist.

Old home becomes a rental. The lender qualifies you under the rental-income, departing-residence and reserve rules.

Old home becomes a second home. Its full payment counts as a monthly debt. No rental offset is available.

Old home is under contract to sell. The old payment can drop out of the ratio, but only with an executed sales contract and confirmation that financing contingencies have cleared. Being merely listed does not do it.

Here is the catch most borrowers miss. If you list the house and say you will sell it, the lender still counts both payments until that contract is firm.

The Rental Path, Step by Step

This is where the rules changed most. Fannie Mae’s departing-residence rule allows a primary residence you will vacate and convert to an investment property when you buy a new primary residence. The steps:

1. Document the current housing payment. Without it, no rental income from the old home can be used.

2. Support the rent with market evidence. Fannie Mae’s announcement SEL-2026-08 moved to a framework built on market-supported rents, reserves and limits on the payment offset, rather than lease agreements. Think market-rent documentation, such as an appraiser’s rent analysis, not the tenant’s signed lease. The new approach applies to applications on or after its effective date, and lenders may adopt it earlier, so ask which version your lender is following.

3. Run the calculation. The lender multiplies gross monthly rent by 75%, then subtracts the old home’s full payment.

4. Read the result. A positive figure may offset the old home’s payment only. A negative figure is added to your debts.

5. Check reserves. With less than 12 months of property-management experience, six months of the old home’s payment must be verified as reserves. That is on top of any other reserves required.

Run it with modeled numbers, in ratio terms. Say the supported rent, after the 75% factor, falls a bit short of the old payment. The shortfall lands in your debt ratio. If the rent covers the old payment with room to spare, the extra does not count as income under Fannie Mae. It just zeroes the old payment out.

Freddie Mac differs. Its rental income section also uses 75% of gross monthly rent, but the full net rental income is generally usable as income only when a borrower has a year of investment-property management experience. Otherwise it is limited to what offsets the old home’s housing costs. Check with your loan officer which agency your file is headed to, since guidance can be updated.

Older advice told borrowers they needed 30% equity in the old home. That conversion-specific requirement was removed years ago, and lenders now follow standard rental-income and reserve rules. Individual lenders may still add their own overlays.

Pick Your Scenario

That table is the whole article in four rows. Find yours before you talk to anyone.

Where the General Rule Breaks

Bridge or swing loans. A bridge loan creates a contingent liability that counts in your monthly debts. Fannie Mae waives that with a fully executed sales contract and cleared financing contingencies.

Two- to four-unit old homes. Rent is counted only for the tenant-occupied units, and the vacancy factor applies to that rental income, while the borrower-occupied unit produces no rent.

A second home or investment property as the new purchase. Different leverage applies: second homes run to 90%, investment property to 85% on one unit and 75% on two to four. Fannie Mae’s multiple-financed-properties policy then comes into play, with a ten-property cap through automated underwriting. That cap does not apply when the new loan is a principal residence. This lane stops there, since this article is about the home you live in.

Active-duty service members. A service member temporarily absent from a principal residence is considered an owner-occupant, and with multiple borrowers only one needs to occupy and take title.

Reserves for the new home. A one-unit principal residence has no minimum reserve requirement by rule, but automated underwriting can still ask for some. The old home may bring its own. Exact terms depend on the lender’s guidelines, property type, leverage, and a full review of the borrower’s file.

Late surprises. If a new debt surfaces before closing and the recalculated ratio exceeds the ceiling, the loan is not eligible for delivery. Do not open a credit card or finance furniture mid-file.

Keep or Sell? The Decision in Practice

The honest framing is that keeping the old home adds a second set of obligations: two sets of taxes and insurance, possible vacancy, repairs, and a landlord’s duties. In qualifying, only 75% of market rent counts. So the file can look tighter than your real cash flow, or looser, if the rent is strong.

Keeping can make sense when the old loan is one you value and the rent is well supported. Selling tends to be cleaner when the ratio is already near the ceiling or you have no landlord experience and thin reserves. Neither is wrong. They are different bets.

Timing and Occupancy

The standard security instrument requires you to occupy the new home within 60 days of signing and keep living there for at least one year. Lenders verify intent. Misrepresenting occupancy to get better terms causes real problems later, so tell the lender your real plan for both homes.

A practical sequence:

1. Decide the old home’s future (rent, second home, sell).

2. Gather the old mortgage statement, tax and insurance figures.

3. Line up market-rent documentation if renting.

4. Check your reserves against the six-month rule.

5. Hold off on new debt until after closing.

6. Apply, then lock in occupancy plans for the new home.

Pre-Application Checklist

• Current mortgage statement for the old home
• Proof of taxes, insurance and any association dues
• Evidence of market rent, if renting
• Statements showing liquid reserves
• Any landlord history you have
• A clear plan for occupancy of the new home

Key Terms Defined

PITIA: Principal, interest, taxes, insurance and assessments on a property, the full monthly housing cost lenders count.

Departing residence: The home you are moving out of when you buy a new primary residence.

Debt-to-income ratio (DTI): Your monthly debts divided by your gross monthly income.

Reserves: Liquid assets left after closing, expressed as months of payments.

Offset: Rent that cancels out the old payment in qualifying but does not add to your income.

Financing contingency: A contract clause letting a buyer exit if their loan falls through. It must be cleared to remove the old payment.

Next Step

If you are buying a home and want to see whether a conventional loan fits your file, Lendmire can help you compare the options and what each one asks of the file. All program details are subject to lender guidelines and full file review, and nothing here is a commitment to lend.

For your own numbers, request a scenario review with Lendmire.

About Lendmire

Lendmire (NMLS# 2371349) is a mortgage brokerage serving homeowners and home buyers in 16 states. FHA, VA, conventional and jumbo purchase and refinance loans are arranged through wholesale lending channels; Lendmire brokers the financing and the lender underwrites each application. Scotsman Guide named Lendmire a Top Mortgage Workplace in both 2025 and 2026.

References

1. Fannie Mae Selling Guide B3-6-02 Debt-to-Income Ratios

2. Fannie Mae Selling Guide B3-6-06 Qualifying Impact of Other REO

3. Fannie Mae Selling Guide B3-3.8-05 Departing Residence

4. Fannie Mae SEL-2026-08 Announcement

5. Freddie Mac Guide Section 5306.1 Rental Income

6. Fannie Mae Selling Guide B2-2-03 Multiple Financed Properties

7. Freddie Mac Guide Section 8405.1