DSCR Loan Calculator: How to Size a Rental Loan by Debt Coverage

What a DSCR Loan Calculator Does

A DSCR loan calculator measures whether a rental property produces enough income to cover its own loan payments. Unlike a conventional mortgage that qualifies you on personal income and debt-to-income ratio, a DSCR loan qualifies the property. The key output is the debt service coverage ratio: net operating income divided by annual debt service.

The calculator takes rental income, operating expenses, and the proposed loan payment, then returns the ratio a lender would look at. A result of 1.00 means the property breaks even on debt. Above 1.00 means income exceeds the loan payment. Below 1.00 means the property does not cover its own debt from operations.

The DSCR Loan Formula

Net operating income is gross rent minus operating expenses such as taxes, insurance, management, maintenance, and vacancy, but before the mortgage. Annual debt service is the total of twelve monthly principal-and-interest payments, and some lenders add taxes and insurance to that figure.

Because financing sits in the denominator, the interest rate and loan term move DSCR directly. A longer term lowers the payment and raises DSCR, while a higher rate raises the payment and pushes DSCR down.

How Much You Can Borrow

A DSCR loan is often sized backward from the ratio the lender targets. If a lender wants a minimum DSCR and knows the property NOI, the maximum annual debt service is NOI divided by that target ratio. From there the loan amount follows from the rate and term.

This is why raising rent, cutting an expense, or increasing the down payment can change approval. Each one changes either NOI or the required payment, which changes the ratio.

• Higher NOI raises DSCR and supports a larger loan.
• A larger down payment lowers the loan payment and raises DSCR.
• A higher interest rate raises the payment and lowers DSCR.
• Adding taxes and insurance to debt service, as some lenders do, lowers the reported ratio.

Worked Example

Suppose a rental produces $30,000 of NOI per year. The investor is considering a loan with an annual debt service of $24,000. DSCR equals 30,000 divided by 24,000, or 1.25. That means income covers the payment with 25% left over.

If the rate rises and annual debt service climbs to $28,000, DSCR falls to about 1.07. The property still covers the loan, but the cushion is thin, and a lender with a 1.20 minimum may ask for a larger down payment or a lower rate buydown.

Common Mistakes to Avoid

• Using gross rent instead of NOI, which overstates the ratio.
• Forgetting vacancy and management, two expenses that quietly reduce NOI.
• Assuming every lender defines debt service the same way; some include taxes and insurance.
• Treating the calculator output as an approval rather than an estimate to discuss with a lender.

Frequently Asked Questions