The exact DSCR formula lenders use, three worked examples with real numbers, and the adjustments that quietly sink a ratio before underwriting.
TL;DR: DSCR equals the property's gross monthly rent divided by its total monthly debt service, which includes principal, interest, taxes, insurance, and any HOA dues. A ratio of 1.00 means the rent exactly covers the payment. Most lenders want 1.20 or better for the cleanest pricing, and many will still lend down to 1.00 or even below with a rate adjustment and lower leverage. The number that matters is the lender's calculation, not yours, and the two differ most often on which rent figure and which insurance quote get used.
The exact formula lenders use to calculate DSCR, three worked examples with real numbers, and the underwriting adjustments that move your ratio before a lender ever quotes you.
The formula is gross monthly rent divided by PITIA: principal, interest, taxes, insurance, and HOA.
Lenders use the lesser of actual lease rent and appraiser market rent on Form 1007, so an above-market lease will not rescue a thin ratio.
A 1.20 DSCR is the common threshold for best pricing; 1.00 to 1.19 usually costs a rate adjustment, and below 1.00 means lower leverage.
Interest-only payments raise the calculated DSCR because the payment used in the denominator is smaller, which can move a deal into a better tier.
The three most common reasons a ratio drops at underwriting are a stale insurance quote, a post-sale tax reassessment, and forgotten HOA dues.
What is the DSCR formula? DSCR equals gross monthly rent divided by total monthly debt service. Debt service is PITIA: principal, interest, property taxes, insurance, and any HOA or condo dues. Rent of $2,400 against a $2,000 PITIA payment produces a 1.20 DSCR.
What is a good DSCR for a rental property loan? 1.20 or higher gets the cleanest pricing at most lenders. Between 1.00 and 1.19 you can still close, typically with a modest rate adjustment. Below 1.00 the property does not cover its own payment, so expect reduced leverage, a rate adder, or both.
Does DSCR use gross rent or net operating income? For one to four unit residential DSCR loans, lenders use gross monthly rent, not NOI. Vacancy, maintenance, and management are not deducted. Larger multifamily and commercial loans do use NOI, which is why the same property can show two very different ratios.
Which rent number does the lender use? Typically the lesser of the in-place lease rent and the appraiser's market rent estimate on Form 1007. On a vacant property, market rent alone is used, and some lenders apply a haircut of 10 to 25 percent.
Can interest-only payments improve my DSCR? Yes. Interest-only removes principal from the payment, which shrinks the denominator and raises the ratio. A file at 1.08 amortizing can price near 1.25 interest-only, which is often the difference between a rate adder and no adder.
How do short-term rentals get calculated? Most lenders use a trailing twelve month revenue statement or an AirDNA style projection, divided by twelve, and often discounted for seasonality. Expect a stricter DSCR floor on short-term rental files than on long-term leases.