DSCR — Debt Service Coverage Ratio — is the single number most DSCR lenders build their entire underwriting decision around. If you’re comparing an investment property or shopping DSCR loan programs, knowing how to calculate it yourself (even roughly) makes it much easier to evaluate a deal before you’re deep into an application.
Just need the formula and a quick example? See DSCR formula for rental property, or run your numbers in the DSCR calculator. For full qualification criteria, see DSCR loan requirements.
The DSCR Formula
At its core, DSCR is a simple ratio:
DSCR = Gross Rental Income ÷ Total Monthly Debt Obligation (PITIA)
PITIA stands for Principal, Interest, Taxes, Insurance, and Association dues (if applicable). It represents the full monthly carrying cost of the mortgage — not just principal and interest.
Step 1: Determine the Rental Income Figure
Lenders generally use one of two sources for the rental income side of the equation:
- Actual lease income — the rent currently being collected under a signed lease, for an existing rental.
- Market rent — an appraiser’s opinion of achievable rent, typically documented on a rent schedule (Fannie Mae Form 1007 or similar), used for a purchase or a property without a current lease.
Which figure a lender uses — and whether they take the lower or higher of the two when both exist — varies by lender and program.
Step 2: Add Up the Full Monthly Debt Obligation
This is where investors most often underestimate the denominator. PITIA includes:
- Principal and interest on the proposed loan
- Property taxes (monthly equivalent)
- Homeowners/landlord insurance (monthly equivalent)
- HOA dues, if the property has them
Leaving out taxes, insurance, or HOA dues will make a property look like it has a stronger ratio than it actually does — which is a common mistake when investors run their own back-of-envelope numbers.
Step 3: Divide
Once you have both figures, divide rental income by PITIA. The result is the property’s DSCR. A ratio above 1.0 generally suggests the property’s rent covers its full monthly carrying cost; a ratio below 1.0 generally suggests it does not, on paper. What a lender is willing to do with a given ratio — and where their eligibility line sits — depends on the specific lender and program.
Worked Example
Say a rent schedule supports $2,400/month in market rent for a property, and the proposed loan’s full PITIA payment is estimated at $2,100/month. Dividing $2,400 by $2,100 gives a DSCR of approximately 1.14. That’s a simplified illustration to show the mechanics of the calculation — actual underwriting also depends on the specific lender’s documentation requirements and how they treat the rent figure.
Why the Ratio Matters Beyond Approval
DSCR isn’t only a qualification hurdle — it’s a useful lens for comparing deals against each other. Two properties at the same price can have very different ratios depending on rent potential, property taxes, insurance costs, and HOA dues. Running the calculation before you’re under contract can help you compare multiple properties on a more consistent basis, alongside your own return targets.
Frequently Asked Questions
Does DSCR include vacancy or maintenance costs?
The standard DSCR formula used for loan qualification typically does not subtract vacancy, maintenance, or property management costs — it compares gross rent to PITIA. Investors modeling their own cash flow for investment purposes may want to layer those costs in separately for a fuller picture.
What if my property doesn’t have a lease yet?
Lenders typically rely on an appraiser’s market rent estimate in that scenario, documented through a rent schedule completed at the time of appraisal.
Can I improve my DSCR before applying?
Some investors adjust the loan amount, put more down, or shop rate/term combinations to change the PITIA side of the equation, which changes the resulting ratio. Whether that’s worthwhile depends on your overall goals for the deal.
Common Mistakes When Calculating DSCR by Hand
A few errors show up repeatedly when investors run their own quick DSCR math before talking to a lender:
- Using principal and interest only. Leaving out taxes, insurance, and HOA dues understates the true monthly obligation and overstates the ratio.
- Using list-price rent instead of supportable rent. Listing sites often show optimistic asking rents; the figure that matters for underwriting is what an appraiser will actually support.
- Forgetting HOA or flood insurance on condos and coastal properties. These costs can be substantial and are easy to overlook in a quick calculation.
- Using a rate that’s no longer current. DSCR is sensitive to the interest rate assumed in the payment calculation, so an outdated rate can meaningfully skew the result.
How Lenders Verify the Rent Figure
For a purchase, lenders typically rely on a rent schedule completed by a licensed appraiser as part of the appraisal, which analyzes comparable rental properties in the area to arrive at a supportable market rent. For a refinance on a currently leased property, lenders often use the actual lease in place, sometimes compared against the appraiser’s market rent opinion, taking whichever the specific program calls for (commonly the lower of the two, though this varies by lender). This verification step is why a DIY DSCR estimate using an online rent estimator can differ from the number that ultimately gets used in underwriting.
DSCR at Different Interest Rate Scenarios
Because DSCR is sensitive to the monthly payment, and the monthly payment is sensitive to the interest rate, the same property’s ratio can look meaningfully different depending on prevailing rates at the time of application. This is one reason it’s worth re-running the calculation close to when you’re actually applying, rather than relying on a rough estimate from weeks or months earlier — and why comparing rate/term combinations across lenders, rather than assuming a single rate applies everywhere, is part of shopping a DSCR loan properly.
Is a higher DSCR always better?
Generally, yes, from a qualification and risk standpoint, but a very high ratio can also mean you’re putting more money down than necessary or under-leveraging a deal relative to your goals. The “right” ratio depends on your own strategy, not just what qualifies.
Does DSCR change after closing?
The ratio used for qualification is a snapshot at closing. After that, your property’s actual performance (rent collected vs. actual expenses) may differ from the underwritten figures, which is a separate, ongoing cash-flow consideration from the DSCR used to originate the loan.
Want to run your own numbers? Our DSCR calculator walks through this formula for your specific property, and our rental cash flow calculator can help you look beyond DSCR at overall property cash flow. For a broader look at what lenders evaluate, see our article on DSCR loan requirements.
Calculate Your DSCR
Once you have a sense of where your property’s ratio lands, the next step is seeing what that could mean for your financing options. Check your DSCR loan eligibility →
FAAS Funding provides business-purpose financing information for real estate investors and businesses. Program availability, terms, pricing, leverage, documentation and eligibility vary by transaction and funding source and are subject to underwriting and applicable requirements. FAAS Funding is not a bank and does not provide legal, tax or investment advice.