Every page-one result for this question is run by someone who wants to originate your loan, and they all answer the same way: “15% to 25%, depending.” That range is technically correct and useless, because it never shows you what each number does to the payment, the cash flow, or the pile of reserves the lender wants to see after you close. The down payment is not one decision. It is three decisions wearing one number.
What follows is the plain mechanics for a 1-10 unit buy-and-hold buyer: the agency thresholds that set the floor, the reserve requirement nobody mentions until underwriting, and a worked example showing how 15%, 20%, and 25% down move your return in different directions. It fits inside the broader question of how to finance a rental property, but here we stay on the cash you bring. No lender is paying me to point you anywhere.
The floor is set by the loan type, not by you
For a conventional mortgage on a property you will not live in, the minimum down payment comes from the agency loan-to-value caps. The current numbers I am working from are the Fannie Mae Eligibility Matrix, checked June 2026. These thresholds move when the guidelines update, so confirm the live matrix before you make an offer:
- Single-unit investment property: up to 85% financing, so 15% down is the floor on a fixed-rate purchase. Below 25% down you also carry mortgage insurance, which eats into cash flow until you reach 20% equity.
- Two-to-four-unit investment property: financing is capped at 75% of value, so 25% down is the floor on a duplex, triplex, or fourplex you do not occupy. There is no getting under that with an agency loan.
- Owner-occupied with rental units: if you live in one unit of a 2-4 unit building, you qualify under owner-occupied rules and the down payment can drop well below the investment floor. That is the entire math behind house hacking.
A DSCR loan sidesteps your personal income and qualifies on the property's rent, but it trades that flexibility for a lower financing cap and a higher rate, so the cash you bring tends to be larger, not smaller. A higher loan-to-value means less cash down; a lower cap means more. The loan you choose sets the floor. You only get to choose how far above it to go.
Reserves: the cash that has to exist after closing
The down payment is not the last check. Lenders want to see reserves, counted in months of the full payment, principal, interest, taxes, and insurance, sitting in an account after you close. For a financed investment property the requirement commonly runs two to six months of that full payment per property, and it climbs as you stack more mortgages. The figure is driven by the agency matrix and the individual lender overlay in force when you apply.
This is why a buyer who scrapes together exactly the down payment gets declined: the underwriter does the down payment math, then asks to see another several thousand dollars that you are not allowed to spend. Plan the reserve as part of the cash to close, not as an afterthought, and keep it separate from your operating float once you own the place.
How 15, 20, and 25 percent down actually compare
Say you buy a single-family rental for $300,000 at a 7.5% fixed rate over 30 years. Rent is $2,400 a month. Taxes, insurance, and a modest maintenance and vacancy allowance run about $700 a month combined. The principal-and-interest payment changes with how much you put down, and so does everything downstream of it.
- 15% down ($45,000): you finance $255,000. The principal-and-interest payment is roughly $1,783 a month, plus mortgage insurance because you are under 20% equity. After the $700 of other costs, cash flow is thin to negative, and your reserve still has to exist on top of the $45,000.
- 20% down ($60,000): you finance $240,000, the payment falls to about $1,678, and the mortgage insurance drops off. That alone swings the monthly result by more than a hundred dollars versus 15% down.
- 25% down ($75,000): you finance $225,000, the payment is roughly $1,573, and cash flow is clearly positive. You have tied up $15,000 more than the 20% case to buy about $105 a month of payment relief.
Now read those same rows as return on the cash you put in. More money down raises monthly cash flow but also raises the denominator, so the cash-on-cash return can fall even as the property looks safer. The 25% case is the calmest to own and often the weakest on percentage return. The 15% case is the opposite. Run your own numbers in the cash-on-cash calculator before you decide which kind of return you are actually buying.
What the down payment does to your taxes and basis
The down payment itself is not deductible, and it does not change your depreciation. Your depreciable basis comes from the building's cost, the price minus the land value, regardless of whether you financed 75% or 85% of it. What does change is the deductible mortgage interest: a smaller down payment means a larger loan and more interest, which is a real deduction but also a real cash cost. Bigger loans deduct more and cost more. The deduction never makes a bad payment good.
One financing trap worth naming up front: if you buy in your own name to get the better rate and later move the property into an LLC, the due-on-sale clause gives the lender the right to call the loan. That is a structuring question to settle before you choose how to take title, not after.
So how much should you put down
Start from the floor your loan type forces, 15% on a single unit, 25% on a 2-4 unit you do not occupy, then add the reserve the lender will demand on top. From there, the choice between the floor and a larger stake is a trade between percentage return and monthly safety. If your goal is the highest return on a limited amount of cash and you can stomach thin early cash flow, you lean toward the floor. If you want a property that sleeps quietly and survives a vacancy, you put down more.
The number that should never enter the decision is the down payment that leaves you with no reserve. A property bought with the last dollar you have is the one that turns a $4,000 furnace into a missed mortgage. Decide the down payment and the reserve together, and treat the reserve as untouchable.
Tracking the loan once it closes
Whatever you put down, the part that quietly matters for years is what happens to each payment afterward. Every mortgage payment splits into deductible interest, non-deductible principal that builds your equity, and escrow for taxes and insurance, and only the interest belongs on Schedule E. Getting that split right is what keeps your net operating income and cap rate honest.
This is the part I built rents.ai to handle, because my own spreadsheets kept folding principal into expenses and overstating my deductions. It models the loan, splits each payment into interest, principal, and escrow, and shows how a given down payment changed your cash-on-cash and equity once the property is in your portfolio. It will not originate the loan or shop your rate, that is still on you and your lender; it only keeps the numbers straight after the money is wired.
The down payment thresholds and reserve ranges here come from the Fannie Mae Eligibility Matrix and were checked in June 2026. Agency guidelines and individual lender overlays change, so confirm the live requirements with your lender before you write an offer. The worked numbers are a hypothetical example to show how the pieces move, not a rate quote or a promise about your deal.