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The formula
NOI means the qualifying net operating income used for the scenario. Annual debt service is the applicable annual principal-and-interest obligation, along with any program-specific payment treatment. Do not mix a monthly numerator with an annual denominator.
An illustrative example
| Input | Illustration |
|---|---|
| Gross annual rent | $36,000 |
| Operating expenses used | $6,000 |
| Illustrative NOI | $30,000 |
| Illustrative annual debt service | $24,000 |
| Result | 1.25 DSCR |
This example is arithmetic, not a Fiirm quote or approval. A lender may use different rent evidence, expense treatment, vacancy assumptions, payment, rate, amortization, or property rules.
Why your number may differ
Ask whether both calculations use the same income basis, operating expenses, debt service, loan amount, rate, amortization, unit count, and property mode. A property-income calculation is not interchangeable with a global borrower-income calculation. If the needed income is not available, a responsible system should return unavailable rather than manufacture a qualifying dollar amount.
Use the ratio as a decision aid
Before applying, use DSCR to spot the variables worth investigating: rent support, expenses, leverage, payment, reserves, and the property’s eligibility. Then compare the result with the applicable program rules. The Mentor can carry the scenario into a program-guided review, but final terms require full underwriting.
Reviewed for public guidance on 2026-08-22 · The Fiirm
The Fiirm provides business-purpose commercial real estate financing only. This page is educational and is not an offer, approval, quote, or commitment to lend. All scenarios are subject to applicable guidelines and full underwriting.