Interest Only vs. Amortizing DSCR Loans: Payment Relief and Remaining Debt

Interest only can leave more cash in the rental account each month. It also leaves the principal unpaid unless you make additional permitted payments. I would put those two results beside each other before calling it better cash flow.

The choice is partly about timing: do you need liquidity now, and can the business support the debt that remains later? A passing ratio during the initial period does not answer the second question.

Start with the payment schedule, not the product label

An amortizing payment contains interest and scheduled principal. An interest only payment covers interest during the stated period. After that period, the contract may require amortization over the remaining term, a payoff, or another specified structure.

Read the actual term, interest only period, amortization period, rate provisions and maturity. A 30 year loan with ten years interest only followed by twenty years of amortization has a different later payment from a 40 year loan followed by thirty years of amortization.

A fixed rate can still have a payment increase when principal repayment begins. An adjustable rate adds a separate source of payment change. Those risks should not be collapsed into one label.

Five years of lower payments leaves a different payoff

Assume two hypothetical $420,000 loans at the same fixed 7.25% rate. One amortizes over 30 years. The other has ten years of interest only followed by twenty years of amortization. Assume no extra principal payments, fees or prepayment charges for this mechanics comparison.

The interest only version retains about $19,658 of payment cash over five years. At that point it also leaves about $23,609 more principal to repay. The difference, about $3,951, reflects additional interest paid because the balance did not decline.

That does not prove amortization is always preferable. Retained cash may fund a necessary reserve or a productive use. But it shows why the payment savings are not free money or a complete return comparison. If actual quotes carry different rates or fees, rerun the model using those differences.

Test what happens when the interest only period ends

Under the assumed ten year interest only contract, the balance is still $420,000 when twenty year amortization begins. At the same 7.25%, the new principal and interest payment is about $3,319.58.

That is approximately $782 more than the initial $2,537.50 payment, an increase of about 30.8%, before taxes, insurance or association changes. If property charges remain $1,000 monthly, total payment rises from $3,537.50 to $4,319.58.

With unchanged hypothetical accepted rent of $5,300, a simple rent divided by payment comparison falls from about 1.50 to 1.23. That is a future stress calculation, not a statement about how a lender must qualify the original loan.

I would also test flat rent and higher insurance, rather than assuming ten years of rent growth will cover the change. The contract payment exists even if the expected refinance does not.

Qualification and operating cash need separate treatment

An investor may qualify an eligible interest only execution on its interest only payment; another execution may impose a different test. The applicable guide, matrix and underwriter's written calculation need to agree.

Before relying on an interest only qualification result, obtain the selected investor’s current calculation and identify whether it uses the initial interest only payment or an amortizing payment. The written approval and loan schedule should make that distinction clear. The numerical comparisons here explain the stated payment schedule; they do not establish approval under a named program.

Likewise, accepted rental income is not automatically cash available after management, repairs, utilities and furnishing replacement. The guide on qualifying versus making money shows that separate ledger.

Changing a payment structure can improve a lender ratio without improving the property's operating performance. The underlying rent, expenses and condition still deserve their own review.

Give the retained cash a job

If I chose interest only for liquidity, I would identify where the saved cash goes: an operating reserve, a planned repair or another defined use. A lower payment that simply supports larger owner distributions leaves the loan balance unchanged with less protection for the later reset.

Compare the cash retained with required reserves, expected capital needs and any prepayment limits on voluntary principal payments. Paying principal later may not automatically reduce the scheduled payment; the contract and servicer's available options matter.

For a planned early sale, include the larger payoff and any prepayment charge. For a long hold, test the scheduled later payment without relying on a new loan. The strategy should work under the documents you sign, even if the hoped for exit takes longer.