Cap Rate vs. Cash-on-Cash Return: Which Number Drives Refi Timing?
Every rental property investor quotes cap rate. Brokers put it in listings. Syndicators cite it to pitch deals. Investors use it to compare markets.
But when it comes to deciding whether to refinance a rental property, cap rate is nearly useless. Here's why — and what actually matters.
What Cap Rate Actually Measures
Cap rate = Net Operating Income ÷ Property Value. It measures a property's income yield relative to its value, completely independent of financing. A $400,000 property generating $24,000/year in NOI has a 6.0% cap rate whether you paid all cash or borrowed $350,000 to buy it.
This financing-independence is exactly what makes cap rate valuable for acquisition analysis — you can compare two properties in different markets on an apples-to-apples basis regardless of how they're financed. It's also exactly why cap rate tells you nothing about refinancing. Refinancing changes your debt structure. It doesn't change NOI. It doesn't change property value. Cap rate doesn't move.
What Actually Drives Refi Timing
Three numbers determine whether a refinance makes sense:
DSCR (after the refi). Does the property's net operating income cover the new monthly payment? DSCR = NOI ÷ P&I payment. Above 1.25 is strong. Below 1.10 is marginal. Below 1.0 means the property can't service its new debt from income alone.
Monthly cash flow change. How much does your after-expense, after-mortgage cash flow improve per month? This is the number that shows up in your bank account each month.
Break-even period. How many months of improved cash flow does it take to recoup your closing costs? Under 24 months is a strong signal. Over 48 months means you need high confidence in your hold period.
Cap rate appears in none of these calculations.
Cash-on-Cash Return: Closer, But Still Incomplete
Cash-on-cash return = Annual Pre-Tax Cash Flow ÷ Total Cash Invested. Unlike cap rate, cash-on-cash does account for financing. But for refi analysis it has two gaps: it doesn't show the change from before to after, and it doesn't account for the time value of closing costs you're paying today. What investors actually need is the present value of the cash flow improvement over the hold horizon — which is what RefiSignal's 10-Year Advantage (PV-adjusted) captures.
Cap Rate Is for Buying. DSCR Is for Refinancing.
A property with a 4.5% cap rate and a 7.5% loan can be a compelling refi candidate. A property with a 7.0% cap rate and a 3.5% loan should almost never be refinanced. Cap rate won't tell you that. The right framework — DSCR, cash flow delta, break-even — will.