How to Calculate DSCR (Formula, Examples, Max Loan)

To calculate DSCR, divide a property's net operating income by its annual debt service. If a rental produces $30,000 of NOI a year and the mortgage costs $24,000 a year, the DSCR is $30,000 ÷ $24,000 = 1.25x. The hard part is constructing the two numbers correctly, because the version that flatters your deal is rarely the version the lender uses.

The Office of the Comptroller of the Currency puts it in one line in its Commercial Real Estate Lending handbook: the DSCR, calculated by dividing NOI by annual debt service, measures the borrower's ability to service its debt. Here is how to build each piece.

Before you start

Gather three things:

• The income. A rent roll or the lease for every unit, plus any other income the property earns (parking, laundry, storage, vending).
• The operating expenses. A trailing-twelve-month expense statement, or line-item estimates for taxes, insurance, utilities, management, maintenance, and reserves.
• The loan terms. The amount, the interest rate, and the amortization period. You cannot calculate annual debt service — or a meaningful DSCR — without all three.

Step 1 — Calculate net operating income (NOI)

NOI is the property's income after operating costs but before financing. Build it in three moves:

1. Start with gross potential rent — what the property earns at full occupancy.
2. Subtract a vacancy and credit-loss allowance. Lenders apply a vacancy factor even on a fully leased building, typically 5% to 10% for stabilized property. Add any other income to get effective gross income.
3. Subtract operating expenses — property taxes, insurance, owner-paid utilities, repairs and maintenance, property management, payroll, marketing, legal and accounting, and a replacement reserve.

What you leave out matters as much as what you put in. Per JPMorgan's commercial term lending guidance, NOI excludes loan payments, income taxes, and one-time capital projects like a roof replacement. The standard list of exclusions:

• Mortgage principal and interest — that is the debt service, the other half of the ratio.
• Depreciation — a non-cash accounting deduction.
• Capital expenditures (CapEx) — large, irregular projects; reserve for them instead.
• Income taxes — these depend on the owner's overall situation.

Mixing any of these into operating expenses is the fastest way to land on a DSCR the lender will not recognize.

Step 2 — Calculate annual debt service

Annual debt service is the total principal and interest paid on the property's debt over twelve months. Three rules keep this honest:

• Include principal and interest. Counting interest alone overstates the DSCR, and it is the error underwriters catch most often. Lenders care about the total cash leaving the deal.
• Annualize it. Use twelve months of payments. Running the ratio on a single month's figure produces a different — and wrong — number.
• Include every loan on the property. A senior mortgage, a second, ground rent, mezzanine debt: all of it counts. If the loan is interest-only, annualize the interest-only payment for the period it applies.

The interest rate and amortization period earn their keep here, a point the commercial-mortgage industry has made for decades.

The same $300,000 of NOI clears 1.25x against a 6.5% loan and falls short against an 8% one. The income held steady — the higher rate raised the debt service.

Step 3 — Divide and interpret

Divide NOI by annual debt service. Express the result to two decimal places — the convention is 1.25x. A one-digit 1.2x or a three-digit 1.247x signals to a commercial lender that you are new to this.

• 1.00x — the income exactly covers the payment, with no cushion.
• 1.25x — a 25% margin. The property's NOI could fall 20% before it hit breakeven.
• Below 1.00x — the property is cash-flow negative; the owner covers the gap out of pocket.

Most stabilized commercial lenders set the floor between 1.20x and 1.25x. You can run the whole calculation in the free DSCR calculator — rent, expenses, and loan terms in, ratio out, no signup and no credit pull.

Worked example: a rental and a commercial building

A single-family rental (residential shortcut). Market rent is $2,400 a month, or $28,800 a year. PITIA — principal, interest, taxes, insurance — runs $2,000 a month, or $24,000 a year. DSCR = $28,800 ÷ $24,000 = 1.20x. Residential DSCR loans use this rent-over-PITIA shortcut because taxes and insurance already sit inside the payment. One catch worth knowing: lenders underwrite the lower of your lease rent or the appraiser's market rent, so an above-market lease gets trimmed to a sustainable number.

A 20-unit apartment building (full NOI). Gross rental income is $480,000 a year. Subtract a 5% vacancy allowance ($24,000) for effective gross income of $456,000, then subtract $156,000 of operating expenses (taxes, insurance, management, maintenance, utilities) for an NOI of $300,000. If the proposed loan carries $240,000 of annual debt service, the DSCR is $300,000 ÷ $240,000 = 1.25x, an example drawn from Clearhouse Lending's CRE analysis.

Reverse it: the maximum loan your NOI supports

Lenders work backward from the income. They take the property's NOI and solve for the largest loan it can carry at their minimum ratio. You can run the same math before you ever ask for a quote:

1. Maximum annual debt service = NOI ÷ minimum DSCR. Using the 20-unit building: $300,000 ÷ 1.25 = $240,000 a year.
2. Maximum loan = maximum annual debt service ÷ the annual loan constant (the yearly payment per dollar of loan at the quoted rate and amortization). At 6.5% over 25 years, the constant is about 0.081, so $240,000 ÷ 0.081 ≈ $2.96 million.

Now change one input. Hold NOI and the 1.25x floor steady, but price the loan at 7.5% instead of 6.5%, and the constant rises to about 0.089 — the same building now supports roughly $2.71 million, about $250,000 less. That is Blackburne's point in numbers: the ratio is only as good as the rate and amortization behind it. If your target loan sits above the ceiling, you close the gap by raising NOI or extending the amortization period.

Business and SBA loans: global DSCR and add-backs

For a business loan, the cash-flow input changes from a property's NOI to the company's EBITDA — earnings before interest, taxes, depreciation, and amortization — but the structure is identical: cash flow divided by debt service.

SBA loans go one step further and use a global DSCR, combining the business and the guarantor:

Global DSCR = (business EBITDA + owner's personal income) ÷ (business debt service + owner's personal debt)

Global DSCR can pull a strong-looking deal under the line. Say a business throws off $250,000 of EBITDA against $190,000 of debt service — a healthy 1.32x on its own. Fold in the owner's $40,000 of personal income and $60,000 of personal debt service (a mortgage, a car, student loans), and the global ratio becomes ($290,000) ÷ ($250,000) = 1.16x, barely clearing the SBA floor. SBA SOP 50 10 sets that floor at 1.15x; most lenders overlay 1.25x, and preferred lenders often want 1.35x.

There is a second trap. SBA lenders rebuild the number from federal tax returns, stripping out add-backs they do not allow — personal auto, meals, cell phones — and applying a market-rate salary to the owner instead of the actual draw.

Because the global ratio depends on your personal cash flow and obligations, it reads off the same picture as your SBA Form 413 personal financial statement. Building a clean, current PFS — assets, liabilities, and income in one place — is what lets you model your own global DSCR before underwriting does. The same exercise underlies calculating net worth for an SBA loan, and StatementsReady builds that statement for you.

Common mistakes lenders catch

The throughline: calculate it the way the lender will. For where that ratio sits in the full approval picture, see what lenders want in 2026; for how the loan itself works, see what a DSCR loan is; and for the borrower-versus-property question, see DSCR vs. personal-income underwriting. More is in the commercial real estate archive.

FAQ

What is the formula to calculate DSCR?

DSCR equals net operating income divided by annual debt service. For a one-to-four-unit rental, lenders use a monthly version: gross rent divided by PITIA (principal, interest, taxes, insurance, and HOA dues). For commercial and five-plus-unit property, they use the annual version: NOI divided by the total principal and interest paid over twelve months. A result of 1.25x means the income covers the debt payment with 25% to spare.

How do you calculate NOI for DSCR?

Start with gross potential rent at full occupancy, subtract a vacancy and credit-loss allowance (typically 5% to 10%), and add any other income like parking or laundry to get effective gross income. Then subtract operating expenses: property taxes, insurance, utilities the owner pays, repairs and maintenance, property management, and a replacement reserve. The result is NOI. Do not subtract the mortgage payment, depreciation, capital expenditures, or income taxes.

Does annual debt service include principal or just interest?

Both principal and interest, for the full twelve months, across every loan secured by the property. Using only the interest portion is the most common mistake and it overstates your DSCR. If the loan is interest-only, annualize the interest payment. If there is a second loan, ground rent, or mezzanine debt, include those payments too.

What is a good DSCR ratio?

Most stabilized commercial lenders want a DSCR between 1.20x and 1.25x, and 1.30x to 1.50x earns the best terms. The minimum varies by property type: multifamily lenders are often comfortable at 1.20x to 1.25x, while hospitality and special-purpose properties usually need 1.40x or higher. A DSCR below 1.0x means the property does not cover its own debt.

How do you calculate the maximum loan amount from DSCR?

Divide your NOI by the lender's minimum DSCR to find the maximum annual debt service the property can support, then divide that by the annual loan constant (the yearly payment per dollar of loan at the quoted rate and amortization). The result is your borrowing ceiling. Because the loan constant moves with the rate and the amortization period, the same NOI supports a smaller loan as rates rise.

How is DSCR calculated for an SBA business loan?

SBA loans use a global DSCR: business cash flow plus the owner's personal income, divided by business debt service plus the owner's personal debt. SBA SOP 50 10 sets a 1.15x floor, and most lenders overlay 1.25x. The lender rebuilds the number from federal tax returns, stripping add-backs it does not allow, so the figure a business broker quotes is often higher than the one the lender calculates.

Run your own number

Calculating DSCR by hand is good discipline; doing it before a lender does is leverage. Run the property math in the free DSCR calculator, then build the personal financial statement your lender folds into the global ratio. Investors scaling a portfolio can track it all through the commercial real estate investor workflow.