How Much Mortgage Can You Afford for an Investment Property

You can afford an investment property mortgage when two separate tests pass: the lender's test (down payment, reserves, and a total debt-to-income ratio at or under the cap) and the property's test (rent covers the payment plus operating costs with room to spare). Agency rules let a one-unit rental go to 85% loan-to-value, require six months of payment reserves through automated underwriting, and cap total DTI at 50%. The second test is the one most new investors skip.

Model your numbers in the investment property mortgage calculator as you read; the worked example below uses the same PITIA and DTI math.

How much down payment does a rental property require?

Freddie Mac's maximum LTV table sets the floors for conforming loans:

Fannie Mae's eligibility matrix uses the same 85% and 75% purchase limits for loans run through its Desktop Underwriter. Lenders can be stricter, and many price a 15%-down rental so much higher (through mortgage insurance and price adjustments) that 20% or 25% becomes the practical choice.

FHA and VA loans are for homes you will occupy. The one route to low-down-payment rental income is buying a 2–4 unit building and living in one unit, which is a primary-residence loan with its own occupancy rules.

Cash to close is more than the down payment

On a $320,000 rental with 20% down, you need $64,000 for the down payment, plus closing costs, plus prepaid escrow for taxes and insurance, plus the reserves described next. If closing costs run 3% of price in your market, that is another $9,600. Ask your lender for a Loan Estimate early; it lists cash to close line by line.

How many months of reserves do lenders want?

Reserves are liquid funds left over after closing. Fannie Mae's minimum reserve rules require, for DU loans:

• Six months of PITIA on the investment property you are buying
• Plus a percentage of the unpaid balances on your other financed properties (including your own home if it has a mortgage): 2% if you have one to four financed properties, 4% for five or six, and 6% for seven to ten

Checking, savings, and the vested balance of retirement accounts can count toward reserves, with haircuts set by the lender. Money borrowed against the property you are buying does not.

The DTI test for investors, step by step

The CFPB describes DTI as all monthly debt payments divided by gross monthly income. For an investor, three pieces go in:

1. Your own housing payment in full — your home's PITIA, or your rent if you rent.
2. Every other monthly debt — car, student loan, minimum card payments, other mortgages (handled through their own rental calculations if they are rentals).
3. The new property's net rental result.

Fannie Mae's debt-to-income limits are 50% for DU loans and 36% for manual underwriting, which can stretch to 45% with qualifying credit score and reserves. There is no separate investor cap; overlays at individual lenders are what you will hear about as "45% for rentals."

The 75% rent rule

For a purchase, Fannie Mae's subject property rental income rule has the lender multiply gross monthly rent by 75% and subtract the property's PITIA. The result is "adjusted net rental income":

• Positive: added to your monthly income
• Negative: added to your monthly debts

The rent comes from a lease or from the appraiser's comparable rent schedule (Form 1007 for one unit, Form 1025 for 2–4 units). If you have less than 12 months of property management experience, a positive result can only offset the property's own PITIA; it cannot add income on top.

Worked example: can this borrower buy a $320,000 rental?

The borrower

• Gross household income: $11,000 a month
• Own home PITIA: $2,300 a month (mortgage balance $310,000)
• Car $450, student loan $250, card minimums $100: $800 a month
• Current DTI: ($2,300 + $800) ÷ $11,000 = 28.18%

The property

• Price $320,000, 20% down ($64,000), loan $256,000 at 7.5% for 30 years
• Taxes $3,840 a year ($320 a month), landlord insurance $1,680 a year ($140 a month)
• Market rent on the appraiser's Form 1007: $2,500 a month

Step 1 — PITIA. Principal and interest on $256,000 at 7.5% is $1,789.99. Add $320 and $140: PITIA = $2,249.99.

Step 2 — Adjusted net rental income. $2,500 × 75% = $1,875. $1,875 − $2,249.99 = −$374.99. It is negative, so it goes into debts.

Step 3 — New DTI. ($2,300 + $800 + $374.99) ÷ $11,000 = 31.59%. That clears both the 45% manual ceiling and the 50% DU cap.

Step 4 — DTI if the rent were not counted. If the lender could not use the rent (no lease and no market-rent schedule, for example), the full PITIA would be a debt: ($2,300 + $800 + $2,249.99) ÷ $11,000 = 48.64%. That passes DU at 50% but fails a 45% overlay. The rent credit is worth 17 points of DTI here.

Step 5 — Reserves. Six months of PITIA is $13,500. Two percent of the $310,000 home mortgage is $6,200. Total required: $19,700, after the down payment and closing costs.

Step 6 — Cash needed. $64,000 down + roughly $9,600 closing (3% assumption) + $19,700 reserves = about $93,300 in verified liquid funds.

The borrower qualifies. Whether they should buy is a different question.

Qualifying is not the same as affording

The lender's 25% rent haircut is a rough stand-in for vacancy and expenses. A real budget is tighter. Using the same property:

The property passes underwriting with room to spare and still loses about $325 a month, or $3,900 a year, before taxes. Depreciation may offset part of that on your return — the after-tax cash flow guide for rentals walks through how — but you would be paying monthly for appreciation and principal paydown. Decide that deliberately, not by accident.

How does the interest rate change what you can afford?

On the same $256,000 loan:

Each quarter point moves the payment by about $43 a month. In the example, the property needed $325 more a month to break even; no realistic rate change closes that gap. Rent, price, or down payment has to move instead.

Expect an investment-property quote to be higher than an owner-occupied quote for the same borrower. The agencies charge loan-level price adjustments for non-owner occupancy, and lenders pass them on through the rate or points. Always compare quotes for the right occupancy type.

What about DSCR loans?

A debt service coverage ratio (DSCR) loan is a non-agency product that sizes the loan on the property's rent relative to its payment rather than your personal DTI. Terms — minimum ratio, down payment, rate, prepayment penalty — are set by each lender, not by Fannie Mae or Freddie Mac, so compare written term sheets. These loans can help self-employed borrowers or investors who have reached agency limits, but you trade documentation ease for price, and the cash-flow test above still applies.

Five levers that raise your borrowing power

1. Get a market-rent schedule or lease. It can cut DTI by more than 15 points, as Step 4 shows.
2. Pay off small installment debts. Removing the $450 car payment drops current DTI by 4.1 points on $11,000 of income.
3. Put down 25% instead of 20%. On the example, the loan falls to $240,000 and P&I to $1,678.11. The monthly cash shortfall shrinks from about $325 to about $213, at the cost of $16,000 more cash up front.
4. Build a management track record. After 12 months of documented rental history (Schedule E or a lease), positive rental income can count as income, not just an offset.
5. Keep reserves separate and seasoned. Lenders verify the source of large recent deposits; money that has sat in your account for two statements is easier to document.

Mistakes that sink investor applications

• Using the seller's tax bill. Many counties reassess at sale. If the bill jumps from $2,400 to $3,840 a year, PITIA rises by $120 a month and both your DTI and cash flow get worse.
• Quoting homeowner insurance. A rental needs a landlord (dwelling) policy. Get the real quote before the lender's underwriter does.
• Counting rent the lender cannot use. A handshake agreement with a future tenant is not a lease. Leases with family members are not allowed under Fannie Mae's rental income rules.
• Draining reserves for repairs right after closing. Reserves are checked before closing, but the reason they exist is the first year of ownership. Keep at least the six months the agency asked for.
• Ignoring your own home's balance. The 2% reserve on other financed properties is calculated on their unpaid balances, so a large mortgage on your primary home raises the cash you need for the rental.

How this fits with the other investor tools

To see the maximum loan your income supports with rent credit built in, use the real estate DTI and borrowing power calculator, and read the DTI guide for real estate investors for how lenders treat existing rentals on Schedule E. Then test the deal itself: the rental property ROI calculator gives cap rate, cash-on-cash return, and DSCR, and the step-by-step guide to analyzing a rental property explains what healthy numbers look like.