DSCR Calculator

Debt service coverage ratio is one number dividing income by debt payment. Above 1.0 the income covers the payment; below it, something else has to. The trouble is that "income" and "debt payment" mean different things to the person lending you money and the person living with the result, and nobody labels which convention they are quoting.

That ambiguity is not academic. On a typical single-family rental the two conventions differ by 0.2 to 0.3. That is the entire distance between a property that clears a conservative investor floor and one that bleeds three hundred dollars a month while holding a signed loan approval.

Residential DSCR lenders divide gross scheduled rent by the full housing payment — principal, interest, taxes, insurance, and association dues. Vacancy is not subtracted. Property management is not subtracted. Repairs, turnover, capital expenditure and leasing fees appear nowhere.

This is not a lender being careless. The ratio is a credit screen sized to the collateral, not a profitability model, and the lender is protected by the down payment long before cash flow matters. It answers "will this rent plausibly service this note," which is a narrower question than the one you are asking.

The investor convention subtracts real operating costs before dividing. Net operating income is gross rent minus vacancy, management, taxes and insurance. Debt service is principal and interest only, because taxes and insurance already came out on the income side. Divide NOI by debt service and you get a ratio that reflects what actually reaches your account.

This calculator applies nine percent vacancy and twelve and a half percent management by default. Those are not conservative for effect — nine percent is roughly one month of turnover every three years plus a few days of friction, and 12.5% sits mid-range for third-party single-family management. If you self-manage you are paying that in hours instead of dollars, and charging zero for it flatters the deal.

Take a $300,000 purchase, twenty percent down, 7.5 percent over thirty years, with $550 monthly tax and $150 insurance. The PITI is $2,378.

At $2,600 rent the lender reads 2,600 ÷ 2,378 = 1.09 and approves. The investor convention nets rent to about $2,070 and reads 0.87 — negative cash flow near $300 a month. At $2,900 the lender reads 1.22 and prices well; you read 0.97, still slightly underwater. You do not cross 1.0 on the investor side until roughly $3,000, and you do not reach a 1.25 investor floor until about $3,730 — by which point the lender is reading 1.57.

The gap never closes. It is structural, because roughly twenty percent of gross rent is spoken for before a dollar reaches the mortgage.

Most residential DSCR programs approve from 1.0, with meaningful pricing improvements above 1.2 and the best tiers above 1.25 — all measured the lender's way. Some will go below 1.0 with a larger down payment, higher rate, or reserves, on the theory that you are covering the shortfall from elsewhere. They are correct that you are. That is the point.

Because the ratio is collateral-driven, DSCR loans generally skip personal income documentation, which is why investors reach for them. The trade is usually a higher rate, a prepayment penalty, and a hard requirement that the appraiser's market rent supports the file — not the rent you hope to get.

A 1.25 investor DSCR means net operating income exceeds debt service by twenty-five percent. That margin is not profit. It is the buffer that absorbs the roof, the eviction, the insurance renewal that jumps forty percent, and the two months the unit sits in a soft rental market.

Underwrite to 1.0 and you have built a property with no tolerance for the ordinary. Every unbudgeted event comes out of your pocket, and the financing that looked cheap becomes the reason you sell at the wrong time.

Using asking rent instead of achieved rent. The number that matters is what comparable units actually lease for, not what a listing hopes for.

Charging zero for management because you self-manage. Your time has a price even when no invoice arrives, and the day you stop wanting to manage, the deal has to survive paying someone who does.

Omitting capital expenditure entirely. Roofs, HVAC and water heaters are not repairs — they are scheduled costs with long intervals. A ratio that ignores them is describing a property that never ages.