The Quick Read: Down payment and rent change the coverage ratio on a duplex. Reserves do not change it, but they can decide whether a lender approves the file. Rent goes in the top of the ratio, and the full monthly payment goes in the bottom. More cash down shrinks the loan and the payment.
- Down payment lowers principal and interest, so the ratio rises. It cannot erase leverage caps, credit floors or reserve rules.
- Rent is the numerator. On a duplex, both units’ rent counts against one building payment.
- Reserves are verified savings held after closing. They sit outside the formula.
- Coverage is not cash flow. Repairs, vacancy, management and utilities are never in the calculation.
- The strongest files clear two tests: enough equity and enough rental coverage.
A duplex is a friendly property for this math. Two rent streams sit over one payment, so a vacant unit hurts, but a healthy pair of units often gives a duplex more cushion than a comparable single-family rental. This guide holds one duplex fixed and moves each lever on its own. Then it moves all three together.
DSCR Calculator
Run the numbers in your market
Rate source: Freddie Mac 30-yr average via FRED® — Federal Reserve Bank of St. Louis · effective Oct 15, 2026
Prefilled with starting assumptions — enter your own rent or nightly figures, taxes, insurance, and HOA for a more accurate picture.
Program parameters update from Lendmire’s centralized guideline source. Taxes and insurance are editable estimates.
As of Oct 15, 2026 · General Freddie Mac market benchmark, not a Lendmire loan offer. Rent, nightly rate, occupancy, taxes, and insurance are editable estimates. Short-term rental figures are estimates only and vary significantly by season, property type, management approach, and local short-term-rental rules — confirm local regulations before relying on them. Qualifying income for short-term rentals varies by program — some use appraisal market rent, others use documented STR history or projections — and is confirmed in underwriting. Not a Loan Estimate, approval, or commitment to lend. Program availability and eligibility are subject to lender guidelines, credit approval, property review, and underwriting.
Key Terms Defined
DSCR (debt service coverage ratio) is the property’s rent divided by its monthly housing payment. A result of 1.00 means the rent just covers the payment.
PITIA stands for principal, interest, taxes, insurance and association dues. It is the full monthly obligation on the property, not just the loan payment.
LTV (loan-to-value) is the loan amount as a percentage of the property’s price or value. An 80% LTV means 20% down on a purchase. Every figure here varies by lender and program — guidelines, property type, leverage, and credit profile all apply.
Reserves are liquid assets you still hold after closing, counted in months of PITIA. Lenders verify them separately from rent.
Rent schedule is the appraiser’s estimate of what each unit would rent for. It comes from the appraisal report, not from your hopes.
Compensating factor is a strength elsewhere in the file, such as a high credit score or deep reserves. It can offset a weaker ratio.
How the Ratio Is Built for a Duplex
A residential DSCR divides total rent by PITIA. Nothing else enters the formula. DSCR loans are designed for non-owner-occupied investment properties, and they are reviewed differently from a standard owner-occupied mortgage. The file qualifies primarily on property-level rental income covering the payment, subject to lender guidelines.
This is not the formula in a finance textbook. The commercial version divides net operating income, which is rent minus operating expenses, by debt service, as Corporate Finance Institute explains. A residential DSCR file skips the expense subtraction. It uses gross rent against the whole housing payment. Mixing up the two versions is where many first-time investors go wrong.
Here are the steps in order:
1. Count the rent. Both units are combined into one figure. The lender uses the appraiser’s rent schedule, often tested against leases.
2. Build PITIA. The loan amount drives principal and interest. Taxes, insurance and any dues are added.
3. Divide. Rent over PITIA gives the ratio.
4. Compare to the program line. Select programs typically start at 1.00. Stronger ratios open better pricing and more leverage.
For a two-unit building, the appraisal form is generally the small residential income property report, Form 1025. Fannie Mae’s appraisal forms page lists it as the form for two- to four-unit properties, and it carries a rent schedule for each unit. The form is named only so you know what the appraiser fills out. The rent it states is the number underwriting works with.
One more point on structure. A duplex is one rental, not two. Both rents go over one payment. A strong rental elsewhere in your portfolio does not rescue a weak duplex when the loans are separate, because each property is tested on its own rent and its own payment.
The Baseline Duplex Used Below
Every table that follows uses one modeled duplex. These are illustrative assumptions, not market data and not a quote.
- The duplex starts at 80% LTV on a purchase of an investment property, and its coverage ratio is 1.05x.
- Taxes, insurance and dues make up roughly a quarter of PITIA.
- The loan terms stay the same in every row.
- Only the lever being tested moves. Final terms depend on lender guidelines, property type, leverage, and the borrower’s complete credit picture.
No dollars appear because the shape of the math matters more than any one price. The calculator on this page can turn the percentages into dollars for your own deal. Treat its output as an illustrative estimate.
Lever One: Down Payment
A bigger down payment lifts the ratio, but only part of PITIA responds. Principal and interest fall with the loan balance. Taxes, insurance and dues do not move. That fixed slice is why the ratio rises by less than the loan shrinks.
| LTV on a purchase | Cash down | Modeled coverage |
|---|---|---|
| 85% | 15% | About 1.00x |
| 80% | 20% | About 1.05x |
| 75% | 25% | About 1.10x |
| 70% | 30% | About 1.16x |
Read the table top to bottom. Each five points of extra cash lifts the ratio by roughly five to six hundredths. The gain is steady, not explosive.
Now read the limits. Across the wholesale network Lendmire works with, purchase leverage on investment properties most often lands at 75% to 80% LTV. Select high-leverage programs reach 85% LTV, which is 15% down, and those generally want a score around 700 or better. The 85% row above is therefore not open to everyone. Eligibility depends on credit, reserves, loan size and the property itself, subject to lender guidelines.
A larger down payment never overrides a credit floor. A 620 floor exists in parts of the network, most programs want around 660, and 700 and above unlocks the strongest leverage tiers. More cash can improve the ratio. It does not turn a 600 score into an eligible one.
The real price of a bigger down payment shows up in your own capital. Moving from 80% to 70% LTV costs ten more points of the price in cash. That cash then cannot serve as reserves or repair money. For a borderline duplex, the better question is often how small a down payment gets you over the line, not how large a down payment makes the ratio look best.
Lever Two: Rent
Rent is the numerator, so it moves the ratio one-for-one. A 10% rise in rent lifts the ratio by 10%. It does not touch the loan amount, the leverage tier or the reserve count.
| Change to the baseline duplex | Modeled coverage |
|---|---|
| Appraised rent 10% lower | About 0.95x |
| Baseline rent | About 1.05x |
| Appraised rent 5% higher | About 1.10x |
| Appraised rent 10% higher | About 1.16x |
| One unit vacant or unsupported | Roughly 0.5x |
The bottom row is the one to study. A duplex has two units, so losing one removes close to half the numerator. Underwriting does not credit rent you hope to collect. If one unit is vacant at purchase, the appraiser’s market rent for that unit usually stands in for a lease, and a lender may ask for the unit to be leased or for a different structure.
Here is the break-even test. Divide the program’s coverage line by your current ratio, then subtract one. If your ratio sits at 0.95x and the line is 1.00x, you need about 5% more rent. The same gap can usually be closed with about 5% more cash down, though that costs real dollars, and a rent increase costs nothing.
Rent is also the lever you control least. The appraiser’s schedule sets the figure, and a rosy lease with a related tenant does not move it. Before you offer, compare the asking rents on both units to what nearby duplexes actually lease for.
Short-Term-Rental Duplexes
A duplex run as a short-term rental sits in a separate lane. Across the network, STR purchase leverage tops out at 75% LTV. Refinance runs around 70%. A cash-out on short-term-rental collateral is held to 70%, versus a 75% ceiling on a standard long-term rental. Expect a score of 640 or better and about 12 months of hosting history. The coverage floor is 1.00 on purchases and refinances. Short-term rental rules can vary by city, county, HOA, and property type, so investors should confirm local rules before relying on projected rental income. These specifics are subject to lender guidelines and a full review of property, leverage, and credit.
Lever Three: Reserves
Reserves do not change the ratio. The formula is rent over PITIA, and savings are not in it. What reserves change is whether the file is approved at all.
Most programs in the network look for about 6 months of PITIA in verified assets after closing. Terms vary by lender, leverage, loan size and transaction type. Conservative rate-and-term files at modest leverage and balances under $1,500,000 can see reserves waived. Loans above that size typically step up to about 9 months. Those are ranges, not promises. If your balance is large, Lendmire’s piece How Much in Reserves and Down Payment Does a Jumbo Loan Require on an Investment Property? covers that tier in detail.
Reserves act as a compensating factor. When coverage is thin, deeper reserves, a higher score or lower leverage can make a lender more comfortable. They buy flexibility. They do not buy coverage.
Reserves also stack on top of the rest of your cash, so it helps to see the full cash picture for the baseline duplex. The items follow.
- The down payment, which is 20% of the price at 80% LTV
- Closing costs
- About six months of PITIA held back in verified assets. Each figure is subject to lender guidelines and a complete review of property type, leverage, and credit.
Terms depend on the lender’s guidelines, the property type, the leverage, and a full review of the credit profile.
Moving to a 70% LTV adds ten more points of price to that stack and leaves the reserves requirement unchanged. Buyers who max out the down payment are often surprised to find themselves short on reserves. The two needs compete for the same savings.
A lender may ask where the funds sit, and a cash-out from another property can sometimes help, subject to the program. The key rule is simple: reserve dollars must be there after the closing.
DSCR vs. conventional financing
There are two common ways to finance an investment property, and they qualify you differently — here’s how investors weigh them.
Why investors choose it
- Qualifies on the property’s rental income — no personal tax returns, W-2s, or pay stubs needed to document income.
- No personal debt-to-income ceiling to clear, so existing mortgages and obligations don’t cap your borrowing the same way.
- Can be closed in an LLC, keeping the property inside a business entity.
- Built for scaling — not held to the limit on number of financed properties that conventional financing applies.
- Underwriting centers on the deal: generally qualifies when the rent covers the payment, a 1.00x coverage ratio being a common baseline (confirmed in underwriting).
- Designed specifically for investment property, including long-term and, where the program allows, short-term rentals.
Where it’s strong
- Often the lowest ongoing financing cost for a buyer who fully qualifies on personal income — a fit for a first property or a cost-first purchase.
Trade-offs for investors
- Requires full personal income documentation and must fit within a debt-to-income limit — salary, existing debts, and other mortgages all count.
- Typically held in your personal name rather than a business entity.
- Caps how many financed properties you can carry, which can become a ceiling as a portfolio grows.
- Evaluates you as a borrower as much as the property, which usually means more paperwork.
How investors usually choose: a first or single property often optimizes for the lowest financing cost; portfolio builders often optimize for leverage, vesting in an LLC, and scaling past conventional caps. The right answer depends on your goals, the property, and current guidelines — both paths run through select lenders in Lendmire’s wholesale network, with eligibility and terms confirmed in underwriting.
All Three Levers Together
Three modeled files on the same duplex show how the levers combine.
| File | Leverage and credit | Coverage | Reserves | Read |
|---|---|---|---|---|
| Stretched | 85% LTV, 700+ score | About 1.00x | About 6 months | Right on the line with the least cash down |
| Middle | 80% LTV, 680 score | About 1.05x | About 6 months | A common profile on most programs |
| Strong | 75% LTV, 720 score, higher appraised rent | About 1.25x | 6 months or more | Most room to adjust, and the most cash tied up |
The stretched file saves cash at closing, but it has no margin. A small drop in appraised rent pushes it below the line. The strong file costs more upfront, and it is the one with options. Both files may or may not be eligible under any given program, since each is underwritten individually.
In practice, the middle file is where many investors land. They trade a little coverage for keeping cash in the bank, which also feeds the reserve requirement. Final terms depend on the lender’s guidelines, the property type, and the borrower’s complete credit picture.
What None of the Levers Fix
Leverage caps. No amount of rent lifts a purchase above a program’s maximum LTV.
Credit floors. A strong ratio does not substitute for a minimum score.
Property eligibility. Manufactured homes (single- and double-wide), log homes and barndominiums are not offered in these programs. Rent and down payment do not change that.
Loan-size rules. Standard programs run up to $3,000,000. Above $2,500,000 the network generally holds to 30-year fixed structures. A larger balance also tends to raise the reserve ask.
Real cash flow. Clearing 1.00x is not positive cash flow. Repairs, vacancy, management, utilities and capital expenses sit outside the calculation. A duplex can pass the lender’s test and still leave you thin each month. Build a separate operating budget, and judge the deal on that as well as on the ratio.
Structures That Change the Math
Three structural options exist beyond the three levers above.
Interest-only periods. Select lenders in the network offer interest-only structures. Some use interest, taxes, insurance and dues as the denominator. That can lift the ratio, but it changes neither rent nor the reserve requirement. The principal you are not paying down stays on the loan. Leverage, reserves, and pricing vary by lender and program; the final terms follow the full file review.
Longer terms. The spine of the network is the 30-year fixed. Extended terms such as 40 years are available through select lenders, and they lower the payment. ARM structures exist for investors who want them.
Coverage below 1.00. Here is the distinction. 1.00 is where many select programs start. A separate select-lender path takes coverage below 1.00, with leverage and terms adjusted. In practice that means less leverage and more cash from you. No-ratio structures are available only through select lenders, generally for borrowers who already own a primary residence, and they price accordingly.
The ratio picture on any duplex also depends on the purchase price. A lower price lowers the loan, which lowers the payment, and that helps coverage the same way more cash down does. Negotiating the price is another form of the down payment lever.
If You Are Short, What to Change First
When the ratio falls just under a program’s line, work through the options in this order:
1. Check the appraised rent. A rent schedule that looks too low may be worth a second look at comparable duplexes.
2. Test a modest drop in LTV. Five points of extra cash lifts the ratio by roughly five to six hundredths in the model above.
3. Look at the structure. An interest-only period or a longer term, where available, lowers the payment without more cash.
4. Consider a different property. A duplex that already clears the line with 20% down beats a weaker one that needs 30%. The exact numbers vary by lender and program and follow a full review of property, leverage, and credit.
5. Check reserves before you commit the cash. Moving savings into the down payment can leave the file short on reserves.
Each step costs something different. Rent costs nothing but is mostly out of your hands. Cash down is fully in your control but ties up capital. Structure is a trade-off against long-term balance.
For the full picture of how programs, credit tiers and property types fit together, see Lendmire’s complete DSCR loans guide.
Frequently Asked Questions
Does a bigger down payment always raise a duplex DSCR?
Yes, because it shrinks the loan and the principal-and-interest portion of the payment. The effect is partial, since taxes, insurance and dues stay fixed. It also has limits. It cannot lift you past the program’s leverage cap, and it does not change credit or reserve requirements. Terms vary by lender guidelines, property type, leverage, credit profile, and full file review.
Can reserves make up for coverage below 1.00?
They can help, but they do not change the ratio. Coverage below 1.00 is available through select lenders in the network, with leverage and terms adjusted. Deeper reserves, a stronger score and lower LTV are the usual strengths a lender weighs on those files. Each file is reviewed individually.
Does the rent come from my lease or from the appraiser?
Underwriting typically leans on the appraiser’s rent schedule, tested against any leases on the property. A lease above market rent is unlikely to carry the file. A lease below market may cap the figure used. Confirm with your broker how the lender will treat each unit before you rely on a number.
Are the rules the same for a short-term-rental duplex?
No. Short-term-rental collateral has its own lane with lower leverage. Purchase tops out at 75% LTV, and cash-out on short-term-rental collateral is held to 70%, compared with 75% on a standard long-term rental. Expect a 640 or higher score and about 12 months of hosting history. Exact terms depend on the lender’s guidelines, property type, leverage, and a full review of the borrower’s file.
Does passing the ratio mean the duplex will make money?
No. The ratio compares rent to PITIA only. Vacancy, repairs, management and utilities are not part of it. Think of it as the lender’s test of whether the rent covers the payment, not a measure of your profit.
Next Step
If you are buying or refinancing a rental property and want to see how the numbers work, Lendmire can help you compare DSCR loan options based on the property income, credit profile, leverage, and investor goals. Lendmire is a mortgage broker arranging financing through select lenders in its wholesale network across 41 markets, including Washington, D.C. Programs change, and each file is underwritten individually. Nothing here is a commitment to lend. Tax treatment varies; consult a qualified professional.
About Lendmire
Lendmire, NMLS# 2371349, is a mortgage brokerage focused on investor financing, arranging DSCR loans in 40 states plus Washington, D.C. — 41 markets total. Qualification is based on the property’s income rather than personal income documentation, subject to lender guidelines, making it a fit for LLC-held rentals and scaling portfolios. Scotsman Guide named Lendmire a Top Mortgage Workplace in both 2025 and 2026.
Get Started
Ready to find the right loan for you?
In about 30 seconds you can review financing options available for your investment property. No commitment required.
Informational only. Not a Loan Estimate, approval, or commitment to lend. Program availability and eligibility are subject to lender guidelines, credit approval, property review, and underwriting.
References
1. Debt Service Coverage Ratio
2. Fannie Mae’s appraisal forms page
This article is part of Lendmire’s DSCR loan program — full qualification details, guidelines, and scenarios live on the program page.
Related reading: DSCR Down Payment Source Rules on a BRRRR Purchase · How to Document Guest-House Rent on a Luxury Airbnb DSCR Loan · Does Guest-House Rent Count on a Super Jumbo DSCR Loan?
Brandon Miller
Founder & CEO, Mortgage Loan Originator, Lendmire LLC
- Mortgage Loan Originator · NMLS# 1129696 · Verify on NMLS Consumer Access
- North Carolina Real Estate Broker · License# 343312 · Verify on NCREC
- North Carolina Insurance Producer · License# 19053198 · Property, Casualty, Life, Health · Verify on NAIC SBS
- Lendmire LLC · Firm NMLS# 2371349 · Verify firm licensure
Disclosure information. Lendmire is a state-licensed mortgage brokerage under NMLS# 2371349. Lendmire is not a depository institution, direct lender, or financial advisor — all loans referenced are placed through wholesale lender partners and are subject to each lender's underwriting standards. This article is provided for general informational purposes and is not a commitment to lend, nor does it constitute financial, legal, or tax advice. Loan programs, terms, rates, and qualification standards change without notice and depend on borrower profile, property type, and the state in which the subject property is located. Equal Housing Opportunity provider. NMLS Consumer Access: nmlsconsumeraccess.org.