Repayment vs Interest-Only Mortgage: Which Is Better for Investors?

With a repayment mortgage (also called an amortizing loan), every monthly payment covers a portion of interest and a portion of principal. Early on, most of the payment goes to interest. Over time, more goes to principal. By the end of the term the loan is fully paid off and you own the property outright.

With an interest-only mortgage, you pay only the interest each month. The principal balance stays the same for the duration of the interest-only period (often 5-10 years, sometimes the full term). At the end, you still owe the full original loan amount and must either refinance, sell, or start repaying principal.

Interest-only payments are significantly lower because you are not paying down principal. On a $200,000 loan at 7% over 30 years:

That $164/month difference goes straight to your cash flow. For an investor screening deals on cash-on-cash return, interest-only makes almost every property look better on paper in Year 1.

Higher cash flow comes at a cost: you are not building equity through loan paydown. After 10 years on a repayment mortgage, a meaningful chunk of your original loan has been paid off. After 10 years on interest-only, you owe the same amount you started with.

This matters most at exit. When you sell the property, the remaining loan balance is subtracted from the sale price. A repayment borrower keeps more of the proceeds. An interest-only borrower keeps less, because the full loan is still outstanding.

If you are relying on appreciation to build wealth, interest-only can work. But if the property does not appreciate (or falls in value), you are left with no equity buffer at all.

The impact on IRR is nuanced. Interest-only often produces a higher IRR on shorter holds (under 5 years), because you put less cash out each month and the exit proceeds are only slightly lower (you have not missed much principal paydown yet).

On longer holds (10+ years), repayment tends to catch up or win, because the equity built through loan paydown adds up and boosts your net exit proceeds. The crossover point depends on the interest rate, appreciation rate, and hold length.

The best way to compare: run the same deal twice in the Real-Estate Analyzer with identical inputs but different loan structures, and check the IRR at your planned exit year.

Interest-only suits investors who:

• Prioritize monthly cash flow above all else
• Plan a short hold (under 5 years) with a clear exit strategy
• Want to deploy the saved capital into additional deals
• Are confident in strong appreciation in their market

Repayment suits investors who:

• Want to build equity steadily and own the property free and clear
• Plan a longer hold (10+ years)
• Prefer a safer position with a declining loan balance
• Are less dependent on monthly cash flow maximization

The biggest risk with interest-only is what happens when the interest-only period ends. If you have not sold or refinanced, your payments jump significantly as the loan converts to a repayment schedule over the remaining term. On a 30-year loan with a 10-year interest-only period, the remaining 20-year repayment schedule means higher monthly payments than a 30-year repayment loan from day one. Always model this transition and make sure you have a plan for it. Use the stress test approach to see how your cash flow holds up in that scenario.