How Is DSCR Calculated for a Commercial Property Loan?

DSCR for a commercial property loan is the property's annual net operating income divided by its annual debt service — the one ratio every commercial mortgage decision runs through before a lender looks at your credit score, your track record, or your story. It answers a single question: can the building pay for the debt? That answer decides whether the deal is bankable and, just as often, how large the loan can be.

Illustrative DSCR calculation, priced on the 10-year Treasury as of October 1, 2026. A building with $280,800 of net operating income asks for a $3,000,000 loan on a 30-year amortization. Price it at the 10-year Treasury, 5.24% on October 1, 2026 (FRED DGS10), plus an assumed 1.51-percentage-point lender spread: 6.75%. Annual principal and interest is $233,495, so DSCR = $280,800 ÷ $233,495 = 1.20x. The building, the spread and the loan are illustrative, not a quote.

The 10-year rose 60 basis points between August 25 and October 1, 2026. At an unchanged spread, that cut the loan this building supports at a 1.25x test by $186,515, and turned a $3,000,000 request that cleared 1.25x into one that does not. That is arithmetic on dated observations, not a forecast.

The formula is one line. The fight is over the inputs: what counts as income, which payment gets used, and whose assumptions win. This guide works through all of it on that example, shows the calculation lenders actually run — the same formula backward — and shows what one dated, published lender minimum looks like.

How do you calculate DSCR on a commercial property?

You calculate DSCR on a commercial property by dividing the property's annual net operating income by its annual debt service — all principal and interest owed on the loan for the year. A property producing $280,800 of NOI against $233,495 of annual loan payments carries a DSCR of 1.20x: income covers the debt 1.2 times over.

1. Build net operating income: rents and other income, less vacancy and credit loss, less every operating expense.
2. Compute annual debt service: twelve monthly principal-and-interest payments on the loan being requested.
3. Divide: NOI ÷ annual debt service = DSCR, written as a multiple such as 1.20x.

Both inputs belong to the same property and the same proposed loan, and both are the lender's versions rather than the ones on your spreadsheet. What trips up borrowers is never the division. It is that underwritten NOI and underwritten debt service are computed by rules, and those rules are the next two sections.

What is the DSCR formula in commercial real estate?

The DSCR formula in commercial real estate is net operating income divided by annual debt service — DSCR = NOI ÷ (annual principal + interest) — with both figures stated as annual totals for the same building and loan request. A ratio of exactly 1.00x means the property earns precisely its debt payment, one bad month from a shortfall.

That is why lenders demand a cushion above 1.00x: Freddie Mac's Optigo fixed-rate term sheet, dated April 2026, sets a 1.25x minimum amortizing debt coverage ratio, and every other lender sets its own. The division itself is never the hard part; the arguments are all upstream of it, in how each side of the fraction gets built.

What counts as net operating income in a DSCR calculation?

Net operating income is effective gross income — scheduled rents plus other income, minus vacancy and credit loss — less all operating expenses: property taxes, insurance, management, repairs, utilities, and administrative costs. It excludes debt service itself, depreciation, income taxes, and capital expenditures. Lenders recalculate NOI to their own underwriting rules rather than accepting the owner's figure.

Three adjustments show up in nearly every underwritten NOI, and each one moves the ratio:

• A vacancy floor. Even a fully occupied building gets underwritten at a minimum vacancy factor — commonly 5%, higher in soft submarkets — because the lender is sizing a multi-year loan, not a snapshot.
• An imputed management fee. Self-managing owners often leave management out of expenses; underwriters add one back, typically 3-5% of effective gross income, because the lender must assume it may someday operate the building with paid management.
• Replacement reserves. Many lenders — agency lenders as a rule — deduct an annual capital reserve (for multifamily, commonly around $250 per unit) before computing the ratio, so their underwritten NOI sits below the accounting NOI.

The methodology question worth asking every lender upfront: trailing-12 actuals, or pro forma? A stabilized deal is underwritten on trailing actuals; a value-add story may get partial credit for projected rents, usually haircut for conservatism. The same building can clear one lender's DSCR test and miss another's without a single number on the rent roll changing.

What counts as debt service — and does interest-only change the ratio?

Debt service is the annual principal and interest on the proposed loan — taxes and insurance are already inside NOI as operating expenses, so they are not counted again. An interest-only period raises the in-place ratio because payments drop to interest alone, but many lenders, agencies included, underwrite to the fully amortizing payment regardless.

The numbers make the point. A $3,000,000 loan at 6.75% on a 30-year amortization costs $19,458 a month — $233,495 a year. The same loan interest-only costs 6.75% of $3,000,000, or $202,500 a year. Against $280,800 of NOI, that is the difference between a 1.20x and a 1.39x DSCR ($280,800 ÷ $202,500 = 1.39) — same building, same loan amount, same rate.

This is why the underwriting convention matters more than the payment schedule. Freddie Mac's April 2026 fixed-rate term sheet, for one, calculates the ratio for partial- and full-term interest-only loans on an amortizing payment. A lender that underwrites the amortizing payment is protecting itself against the day the IO period ends; a lender that underwrites the IO payment is giving your deal credit for near-term cash flow. Neither is wrong, but they produce different maximum loans on identical deals — one of several reasons quotes on the same property can differ far more than the rates printed on them.

What does a full DSCR calculation example look like?

Take an illustrative 20-unit apartment building renting at $2,000 per unit per month, financed with a $3,000,000 loan at 6.75% over 30 years. Working from scheduled rents down to NOI and dividing by the annual payment produces a DSCR of 1.20x — the arithmetic below shows every step.

Now the debt side. A $3,000,000 loan at 6.75% fixed — the 10-year Treasury's 5.24% on October 1, 2026 plus the assumed 1.51-point spread — on a 30-year amortization pays $19,458 per month, or $233,495 per year.

What is the DSCR on that worked example?

The worked example comes out at 1.20x — $280,800 of net operating income divided by $233,495 of annual principal and interest — which is the building earning $1.20 for every $1.00 of debt payment due that year. It fails a 1.25x test, and it leaves about a sixth of income, $47,305, as cushion before the payment goes uncovered.

Run your own property through the free underwriting calculator to see where your rent roll and expense load actually land, then treat the result as a starting point rather than a verdict — the vacancy floor, management add-back, and reserve deduction described above are all applied afterward, by the lender.

How do lenders use DSCR to size a commercial loan?

Lenders run the formula backward: divide underwritten NOI by the required DSCR to get the maximum annual debt service the property supports, then divide that by the loan constant to get maximum proceeds. On $280,800 of NOI at a required 1.25x, the ceiling is $224,640 of debt service — about $2.89 million of loan.

Step by step on the example deal, against a lender requiring 1.25x coverage:

1. Maximum debt service: $280,800 ÷ 1.25 = $224,640 per year.
2. Loan constant: at 6.75% and 30-year amortization, a loan pays about 7.78% of its balance per year in principal and interest — an annual constant of 0.0778.
3. Maximum proceeds: $224,640 ÷ 0.0778 ≈ $2.89 million ($2,886,225 with the unrounded constant).

So even though the borrower asked for $3,000,000 — and even if the loan-to-value math supports it — this lender's proceeds top out around $2.89 million. That is a DSCR-constrained deal: the coverage test, not the appraisal, sets the loan. In higher-rate environments most deals are DSCR-constrained, because rate feeds directly into the constant.

Rate sensitivity is worth seeing once. Move the same 30-year loan from 6.75% to 7.00% and annual debt service on $3,000,000 rises from $233,495 to $239,509 — the DSCR falls from 1.20x to 1.17x with no change to the building whatsoever. That is why proceeds quotes drift with the market between term sheet and close: the 10-Year Treasury Constant Maturity yield rose from 4.64% on August 25 to 5.24% on October 1, 2026, and at an unchanged assumed spread that move alone took this building's 1.25x loan from $3,072,740 to $2,886,225. SOFR, the base for floating quotes, was 3.88% on October 2, 2026, per the Federal Reserve Bank of St. Louis (FRED). Current levels sit on current commercial mortgage rates.

The practical consequence: getting maximum proceeds is a shopping problem. Required DSCRs, vacancy floors, reserve deductions, and IO underwriting conventions all differ by shop, so the same NOI supports different loan amounts at different lenders — sometimes by hundreds of thousands of dollars. YieldStack is a commercial mortgage brokerage. It runs this math before your deal goes out, computing the DSCR the way credit teams will, and matches the deal against 20,000+ loan programs whose coverage rules the property actually clears.

How is commercial DSCR different from DSCR on a 1-4 unit rental loan?

Commercial DSCR and 1-4 unit DSCR divide different things, which is why the two ratios cannot be compared even when they carry the same number. Residential programs divide gross rent by the full housing payment of principal, interest, taxes, insurance and association dues, with no expense deduction. Commercial DSCR divides NOI, income after all expenses, by principal and interest alone.

That difference changes what the ratio means. A 1.20x on a commercial loan means the property clears its debt by 20% after paying every operating bill; a 1.20x on a rental-home program means rent exceeds the housing payment by 20% before repairs, vacancy, or management. Marketing pages and even loan officers blur the two constantly — a confusion our guide to what investors get right and wrong about DSCR loans untangles at length. For the full picture of the loan product itself, start with the DSCR loan guide.

What DSCR do commercial lenders require in 2026?

There is no single commercial DSCR minimum in 2026, because each lender and loan program sets its own and changes it by property type, loan size and market. One dated, published example is Freddie Mac's Optigo fixed-rate multifamily term sheet, dated April 2026, which sets a 1.25x minimum amortizing debt coverage ratio, subject to adjustment. Otherwise, ask.

That Freddie Mac sheet shows how much sits behind one number. Its 1.25x applies to fixed-rate terms from 5 years to longer than 7 years, it is measured on an amortizing payment even during interest-only periods, the program starts at a $10 million loan amount, and the sheet says adjustments may be made depending on the property, product and market. Banks, life companies, CMBS conduits, debt funds and small-balance programs set their own thresholds, and many do not publish them, so for any lender whose current term sheet you have not read, the minimum varies; ask before you size the deal around it. A deal that only just clears a minimum is also competing for allocation against files with more cushion, which shows up as pricing and proceeds long before it shows up as a decline.

Requirements also move with asset class (hotels price to higher coverage than apartments), market, and the lender's own book. The full 2026 threshold map — ratios by property type, credit score floors, and reserve requirements — is in our companion guide to DSCR loan requirements, and the underwriting quirks specific to 5-20 unit buildings get their own treatment in DSCR loans for small multifamily.

How can you improve a property's DSCR before applying?

You can improve DSCR from either side of the fraction: raise underwritable NOI — documented rent increases, other income, expense reductions that survive diligence — or shrink the debt service with a longer amortization, a rate buydown, or simply a smaller loan. Structure can help too, but only with lenders that underwrite the interest-only payment.

A caution on the amortization lever: it moves the ratio more than people expect, and not every lender offers it. Compressing the example loan to a 25-year schedule raises annual debt service from $233,495 to $248,728 — dropping the DSCR from 1.20x to 1.13x — so the difference between a 25-year and a 30-year lender can be the difference between an approval and a decline before pricing is even discussed. The honest levers, though, are the income ones: at a 1.25x requirement and a 0.0778 constant, every extra dollar of documented NOI supports roughly ten more dollars of loan, which is why cleaning up the rent roll and the expense story before underwriting is the highest-yield hour a borrower spends.

The bottom line

DSCR for a commercial property loan is annual NOI divided by annual principal and interest, and the working version of the formula is the lender's: underwritten NOI with vacancy floors, imputed management, and reserves, divided by a payment that may be the amortizing one even during an IO period, then run backward to size the loan.

On the illustrative example, $280,800 of NOI carries a $3,000,000 loan at 6.75% with a 1.20x DSCR and supports about $2.89 million at a 1.25x test, down from about $3.07 million when the 10-year Treasury was 4.64% on August 25, 2026. Minimums vary by lender (Freddie Mac's April 2026 fixed-rate sheet sets 1.25x), and the inputs are negotiable, which makes coverage a shopping problem as much as a math problem. Package the deal once on YieldStack and let programs that fit your DSCR compete →