DSCR Calculator the ratio lenders underwrite on
Enter the property's net operating income and the loan you want. The gauge shows where the coverage ratio lands against the shortfall, thin, acceptable and strong lending zones.
1.25 Is the Usual Bar
Most commercial and investment lenders want income to cover the debt at least 1.25 times.
NOI Excludes the Loan
Net operating income is before debt service. Subtracting the payment first double-counts it.
What is the debt service coverage ratio?
At a Glance
The debt service coverage ratio is how many times a property's operating income covers the loan payments it has to fund. At 1.00 the income exactly matches the payments and there is nothing spare; at 1.25 there is a quarter of the debt service in headroom. It is the single number most commercial and rental-property lenders underwrite on.
The ratio itself is a one-line definition. The work is in getting both halves right.
DSCR = net operating income ÷ annual debt serviceThe numerator is net operating income: gross rent minus every operating cost — management, maintenance, insurance, property tax, a vacancy allowance — but before any loan payment. As Investopedia's definition makes explicit, debt service is the denominator, so subtracting it from the numerator too would count it twice and understate the ratio badly.
The denominator is the annual debt service. Rather than asking you to work the payment out first, this calculator derives it from the loan terms with the standard annuity formula and multiplies by twelve:
M = P × i × (1 + i)ⁿ ÷ ((1 + i)ⁿ − 1), then × 12That coupling matters: change the term or the rate and the ratio moves with the payment, exactly as it would in a lender's own model.
These are the values the calculator loads by default.
Establish net operating income
78,000 a year, after management, maintenance, insurance, tax and a vacancy allowance — and before any loan payment.
Derive the monthly payment
750,000 at 6.5 % over 25 years (300 payments) gives 5,064.05 a month.
Annualise the debt service
5,064.05 × 12 = 60,768.64 a year.
Divide
78,000 ÷ 60,768.64 = 1.28. Income covers the debt roughly one and a quarter times.
Read the headroom
78,000 − 60,768.64 = 17,231 a year, or 1,436 a month of surplus before any capital expenditure.
The bands on the gauge are the ones underwriters actually speak in.
Below 1.00 — shortfall. The property does not pay for its own loan and the gap has to come from elsewhere every month. At 60,000 of income the ratio on this loan falls to 0.99, which is a monthly deficit of 64 before a single repair.
1.00 to 1.25 — thin. Positive but below the usual commercial minimum. It fails most underwriting boxes, and a single vacancy or a tax reassessment erases the margin.
1.25 to 1.50 — acceptable. The standard target. Lenders size loans so that this is exactly what you land on, which is why the ratio is worth calculating before you ask rather than after.
Above 1.50 — comfortable. Room for vacancies, repairs and a rate rise at refinancing.
The term is the fastest lever. The same income and loan amortized over 30 years instead of 25 lifts the ratio from 1.28 to 1.37, because the payment falls to 4,740.51. Over 20 years it drops to 1.16. Nothing about the property changed.
Rate risk shows up here first. At 7.5 % instead of 6.5 %, the same deal falls to 1.17 — below the bar. If you are refinancing into an unknown rate, test the ratio at a rate above today's.
To see the payment on its own, use the Loan Payment Calculator; for the balance over time, the Amortization Schedule Calculator.
What the ratio does and does not capture
This calculator is for informational purposes. The arithmetic is exact; the inputs are where the risk lives.
- NOI definitions vary. Lenders apply their own vacancy factor, management fee and replacement reserve, often stricter than an owner's own figures. Expect their NOI to be lower than yours.
- Capital expenditure is excluded. A new roof or boiler does not appear in NOI but does empty the surplus.
- One loan only. A property with a second charge or mezzanine debt needs the total debt service in the denominator.
- Interest-only periods flatter the ratio. Some lenders test DSCR on a notional amortizing payment instead.
- Global versus property DSCR. Some underwriters test the borrower's whole portfolio, not the single asset.
Verify the ratio against the lender's own underwriting sheet, and consult a qualified financial advisor or accountant before committing to investment debt.