How to Calculate DSCR in Commercial Real Estate (With Examples)
Step-by-step walkthrough of the debt service coverage ratio formula with real-world commercial property examples showing strong, marginal, and weak DSCR scenarios.
The DSCR formula
Debt service coverage ratio measures whether a property generates enough income to cover its mortgage payments. It’s the single most important metric lenders use to determine how much they’ll lend on a commercial real estate deal.
DSCR = Net Operating Income ÷ Annual Debt Service
Where Annual Debt Service = Monthly Mortgage Payment × 12
Step 1: Calculate net operating income (NOI)
Start with the property’s gross rental income — the total annual rent collected from all tenants. Subtract a vacancy and collection loss factor (typically 5%–10%) to get effective gross income. Then subtract operating expenses — property taxes, insurance, CAM/common area maintenance, management fees, and reserves for replacements. The result is your net operating income.
NOI = Gross Rent − Vacancy Loss − Operating Expenses
Important: NOI does not include debt service (mortgage payments), capital expenditures, depreciation, or income taxes. It represents the property’s pure operating performance before financing costs.
Step 2: Calculate annual debt service
Annual debt service is your total mortgage payment for the year — principal plus interest. Use your loan amount, interest rate, and amortization period to calculate the monthly payment, then multiply by 12. If the loan is interest-only, annual debt service is simply the loan balance multiplied by the interest rate.
Step 3: Divide NOI by annual debt service
The resulting ratio tells you how many times over the property’s income covers the mortgage. A DSCR of 1.0x means the income exactly equals the debt payment — no margin for error. Anything above 1.0x means there’s a cushion. Anything below means the property’s income doesn’t cover the mortgage.
Example 1: single-tenant industrial warehouse — NNN lease
Three real-world commercial property scenarios showing how DSCR plays out in practice. The first is the one that works.
Sample inputs
- Purchase price
- $4,200,000
- Building size
- 32,000 SF
- Annual rent (NNN)
- $8.50/SF = $272,000
- Vacancy factor
- 0% (single tenant)
- Management fee
- 3% = $8,160
- NOI
- $263,840
- Loan (60% LTV)
- $2,520,000
- Interest rate
- 6.25%
- Amortization
- 25 years
NOI = $272,000 − $8,160 = $263,840.
Monthly payment = $16,624 → annual debt service = $199,484.
DSCR = $263,840 ÷ $199,484 = 1.32x.
1.32x DSCR — comfortably financeable
Key takeaway
This deal initially modeled at 70% LTV only produced a 1.13x DSCR — below lender minimums. Reducing to 60% LTV brought it to 1.32x. This is exactly why lenders often size loans to a DSCR constraint rather than a fixed LTV — they’ll lend whichever produces the lower loan amount.
Example 2: multi-tenant retail strip center — 28% vacant
Sample inputs
- Purchase price
- $2,800,000
- Building size
- 18,000 SF
- Gross annual rent
- $324,000
- Current vacancy
- 28% (2 of 6 suites)
- Lender vacancy factor
- 10% on occupied
- Operating expenses
- $78,000/yr
- Loan (70% LTV)
- $1,960,000
- Interest rate
- 6.75%
- Amortization
- 25 years
In-place rent (4 occupied suites) = $233,000.
Lender vacancy haircut (10%) = −$23,300.
Effective gross income = $209,700.
Operating expenses = −$78,000.
NOI (lender-underwritten) = $131,700.
Monthly payment = $13,542 → annual debt service = $162,502.
DSCR = $131,700 ÷ $162,502 = 0.81x.
0.81x DSCR — does not qualify for conventional financing
This is a classic value-add scenario. The property has significant vacancy that depresses current income below the debt service threshold. The investor would need to either lease up the vacant suites before seeking permanent financing, use bridge/hard money for the acquisition, or bring substantially more equity to close.
If fully occupied at market rents: NOI would jump to approximately $213,600, producing a DSCR of 1.30x at the same loan amount — well within range. This is why value-add investors focus on the stabilized DSCR when evaluating these deals.
Example 3: office building with a 2-year I/O period
Sample inputs
- Purchase price
- $6,500,000
- NOI (stabilized)
- $455,000
- Loan (65% LTV)
- $4,225,000
- Interest rate
- 6.50%
- I/O period
- 2 years
- Amortization (after I/O)
- 25 years
During the interest-only period:
Annual debt service = $4,225,000 × 6.50% = $274,625.
DSCR = $455,000 ÷ $274,625 = 1.66x.
After the I/O period (fully amortizing):
Monthly payment = $28,528 → annual debt service = $342,330.
DSCR = $455,000 ÷ $342,330 = 1.33x.
1.66x during I/O → 1.33x amortizing — both meet thresholds
Watch the transition
Interest-only periods boost DSCR temporarily by eliminating principal repayment. Always model both the I/O period and the fully amortizing period. Lenders typically underwrite to the amortizing DSCR — if that number doesn’t work, the I/O period is just delaying the problem.
Common mistakes when calculating DSCR
Using gross income instead of NOI
DSCR uses net operating income — after subtracting vacancy, operating expenses, and management fees from gross rent. Using gross rent inflates DSCR and gives a misleading picture of debt coverage.
Ignoring the lender's vacancy assumption
Even if your property is 100% occupied, the lender will apply a vacancy factor — typically 5% to 10%. Your actual DSCR might be 1.40x, but the lender's underwritten DSCR at a 7% vacancy haircut might come in at 1.28x.
Forgetting management fees
Some investors self-manage and exclude management fees. Most lenders add a management fee (typically 3%–5% of effective gross income) regardless of whether you're actually paying one. This reduces your underwritten NOI and DSCR.
Not accounting for reserves
Replacement reserves — typically $0.15 to $0.30 per square foot annually — are deducted from NOI by most lenders. Skipping reserves in your calculation makes your DSCR look better than what the lender will underwrite.
Mixing up loan term and amortization
The monthly payment — and therefore annual debt service — is based on the amortization period, not the loan term. A $3M loan at 6% on a 25-year amortization produces a very different payment than the same loan on a 20-year amortization or interest-only.
Frequently asked questions
Can I calculate DSCR on a property I haven't purchased yet?
Yes — and you should. Calculating DSCR during the underwriting phase tells you whether the deal will qualify for the financing you need. Use the property's current rent roll, market operating expenses, and your expected loan terms to model DSCR before making an offer. If the DSCR doesn't work at your target leverage, you'll know to either negotiate a lower price, plan for more equity, or walk away.
What is the difference between in-place DSCR and stabilized DSCR?
In-place DSCR uses the property's current income — including any vacancies, below-market leases, or other income shortfalls. Stabilized DSCR assumes the property is leased at market rates with a normalized vacancy factor. The gap between the two represents the value-add opportunity. Lenders use in-place DSCR for permanent financing and may accept stabilized DSCR for bridge loans or construction takeout.
How do I improve a property's DSCR?
You can improve DSCR from either side of the equation. On the income side: raise rents to market, lease vacant space, reduce operating expenses, or add ancillary income. On the debt side: increase your down payment to reduce the loan amount, negotiate a lower interest rate, extend the amortization period, or request an interest-only period. The most common quick fix is simply reducing leverage.
Is DSCR the same as debt yield?
No. DSCR measures NOI relative to debt service (the payment). Debt yield measures NOI relative to the loan balance itself (NOI ÷ Loan Amount). Debt yield normalizes for different interest rates and amortization periods — a 10% debt yield means the property produces $0.10 of NOI for every $1.00 of debt. Some lenders, especially CMBS, use debt yield as a primary sizing constraint alongside DSCR and LTV.
Do lenders look at monthly or annual DSCR?
Most commercial lenders calculate and report DSCR on an annual basis — annual NOI divided by annual debt service. Some lenders may review monthly or quarterly DSCR for properties with seasonal income patterns like hospitality or student housing. For most standard commercial property types, annual DSCR is the standard.
Final thoughts
Calculating DSCR isn’t complicated — but getting it right requires using the same assumptions lenders use: vacancy haircuts, management fees, reserves, and the correct amortization schedule. The examples above show how dramatically DSCR changes based on occupancy, leverage, and loan structure.
DealWise AI calculates DSCR automatically from your deal’s rent roll, operating expenses, and financing terms — and updates it in real time as you adjust assumptions. No manual spreadsheet work needed.
Related guides
What is DSCR in real estate?
The complete guide to debt service coverage ratio.
What is a good DSCR?
DSCR benchmarks by property type and lender.
What is NOI?
The income number that determines DSCR.
What is cap rate?
The unleveraged read on the same NOI.
Commercial real estate loan terms
Every financing term explained in plain language.
Amortization vs interest-only
Why the I/O period flatters DSCR, and what happens after it.
Calculators that run these numbers for you
Three examples took a spreadsheet. A rent roll takes a minute.
DealWise AI builds NOI lease by lease and re-sizes debt as you move the terms. Free to start.