When you send a commercial deal to a lender, they don’t start with your credit score or your business plan. They start with one number: can this property pay its own loan, with room to spare? That number is the Debt-Service Coverage Ratio — DSCR — and you can compute it yourself in about five minutes. Doing it before you apply is the difference between finding out you’re short from us, gently, or from three lenders in a row who quietly pass.
The formula is simple: DSCR = Net Operating Income ÷ Annual Debt Service. It’s the property’s yearly income after real expenses, divided by what the loan costs per year. A DSCR of 1.00 means the property earns exactly enough to cover the loan and not a dollar more. Lenders don’t fund 1.00 — they want a cushion, usually 1.20 to 1.25, so a slow quarter or a vacancy doesn’t put the loan underwater. This guide walks you through building each piece honestly, running your own number, and knowing what to do if it comes up short.
Build your NOI honestly
Net Operating Income is gross income minus real operating expenses — and the word that matters is real. Start with everything the property brings in: rents, plus any parking, laundry, or storage income. Then subtract what it actually costs to run: property taxes, insurance, utilities you pay, repairs and maintenance, property management, and a realistic vacancy allowance. What’s left is your NOI.
Two things do not belong in NOI, and this is where owners fool themselves. Your mortgage payment is not an operating expense — NOI is calculated before debt, because the whole point is to test the income against the debt separately. And depreciation is not a real cost — it’s a tax deduction, not money leaving your account, so a lender strips it out. If you pad NOI by leaving out expenses or leave in phantom income, you’re not gaming the lender — you’re just computing a number that will fail their underwriting instead of yours.
Estimate your annual debt service
Annual debt service is what the loan costs you over a year — twelve monthly payments of principal and interest. It’s driven by three things: the loan amount, the interest rate, and the amortization period (how many years the payment is spread over, often 20, 25, or 30 for commercial). A longer amortization means a smaller monthly payment, which raises your DSCR — but note the amortization and the loan term are different animals, and a shorter term is what creates the balloon you’ll refinance later.
You don’t need to do the amortization math by hand. Any mortgage calculator or a single spreadsheet formula gives you the monthly payment from those three inputs; multiply by twelve for the annual figure. If the loan is interest-only for a period, the debt service is just the annual interest — lower now, but underwrite the fully-amortizing payment too, because that’s the number a permanent lender will hold you to.
If the number comes up short
A DSCR under the bar isn’t a dead deal — it’s a math problem with four honest levers. You can borrow less, which shrinks the debt service and lifts the ratio. You can put more down, same effect from the other side. You can raise NOI — real rent increases, cutting a genuine expense, filling a vacancy — though only documented, durable income counts. Or, if the property simply isn’t stabilized yet, you can use a bridge loan to stabilize first and refinance into permanent debt once the income is real.
What doesn’t work is arguing with the ratio. If your honest number is 1.05 and the lender wants 1.25, the gap is the gap — and the useful move is to change one of the inputs, not to hope underwriting rounds up. Running this yourself first means you walk in already knowing which lever you’re pulling.
Run the number: a small mixed-use building
Illustrative only — your real income, expenses, and rate will differ. But the arithmetic is exactly what a lender does. Say you’re looking at a small retail-and-apartments building and considering a $1,200,000 loan.
| Gross annual income | $180,000rents + parking, fully occupied |
|---|---|
| Operating expenses | −$72,000taxes, insurance, utilities, repairs, mgmt, vacancy |
| Net Operating Income (NOI) | $108,000no mortgage, no depreciation |
| Proposed loan | $1,200,0007.0% over 25-year amortization (illustrative) |
| Annual debt service | ~$101,760~$8,480/month × 12 |
| DSCR = 108,000 ÷ 101,760 | ≈ 1.06xbelow a 1.20–1.25 bar |
At 1.06x, you don’t clear the bar — the property covers the loan with almost no cushion, and a single vacancy would put it underwater, which is exactly the risk the ratio exists to catch. Now you know the fix in advance: drop the loan to about $1,020,000 (more down) and the debt service falls to ~$86,500, pushing DSCR to ~1.25x — a deal a lender funds. Had the same NOI faced a $1,000,000 loan, you’d already be at ~1.27x and clearing the bar comfortably. Same building, different ask — the number tells you which ask is real.
Where you stand
Run your own NOI and debt service, divide, and read the result against this. It won’t be a surprise when the lender does the same math.
You likely qualify when
- Your honest DSCR lands at 1.25x or above on the loan you actually want.
- NOI is built from documented income and real expenses — not projections or a stripped expense line.
- The property is occupied and cash-flowing today, not on paper next year.
- The debt service you tested is the fully-amortizing payment, not just an interest-only teaser.
You’re not there yet when
- Your DSCR sits under 1.20x and only clears the bar if you assume best-case rents.
- NOI leans on income that’s a forecast, or looks healthy only because an expense was left out.
- The building is mid-lease-up, vacant, or being repositioned — the income isn’t stabilized.
- The ratio works at interest-only but fails the moment principal is added back.
Common questions
- What DSCR do commercial lenders want?
- Most commercial lenders look for a Debt-Service Coverage Ratio of roughly 1.20 to 1.25 — meaning the property’s net operating income is 20–25% more than its annual loan payments. That cushion protects the loan against a vacancy or a slow quarter. Requirements vary by property type and lender, but a deal below 1.20x is a hard sell almost everywhere.
- What counts in Net Operating Income?
- NOI is gross income (rents plus any parking, laundry, or storage income) minus real operating expenses: property taxes, insurance, utilities you pay, repairs and maintenance, property management, and a vacancy allowance. It is calculated before your mortgage and before depreciation — neither of those belongs in NOI, because the ratio tests the property’s income against the debt separately.
- Does my salary or business income count toward the coverage ratio?
- No. DSCR measures whether the property itself pays its own loan, so it uses the property’s net operating income only — not your paycheck or income from another business. Your personal finances matter to a lender in other ways, such as a personal guarantee or global cash-flow analysis, but they don’t go into the property’s coverage ratio.
- What if my DSCR is under 1.2?
- You have four honest levers: borrow less, put more money down, raise the property’s net operating income with documented rent increases or a genuine expense cut, or use a bridge loan to stabilize the property first and refinance once the income is real. What doesn’t work is hoping the lender rounds up — the fix is to change one of the inputs before you apply.
- Is a higher DSCR always better?
- For qualifying, more cushion is safer and a very high DSCR clears underwriting easily. But an unusually high ratio can mean you’re borrowing less than the property could support, leaving cash on the table you might have used elsewhere. The goal isn’t to maximize DSCR — it’s to clear the lender’s bar with real numbers while sizing the loan to what your plan actually needs.
- How is DSCR different from my personal debt-to-income ratio?
- Personal DTI measures your household debts against your personal income, and it’s what residential mortgage lenders use. DSCR measures a property’s net operating income against that property’s loan payments — the business, not the borrower. Commercial deals are underwritten primarily on DSCR because the property is expected to service its own debt, though a lender may still look at your personal finances for a guarantee.
- Do I need an appraisal to run my own DSCR?
- No — you can run a solid self-check with your own rent roll and expense records plus a rough loan payment from any mortgage calculator. A formal appraisal and the lender’s own expense assumptions may adjust the NOI later, sometimes downward, so build your number conservatively. Running it yourself first tells you whether you’re comfortably over the bar or right on the edge before you spend money on the deal.