Cap Rate vs. Cash-on-Cash Return: What Each One Actually Tells You

Every rental property calculator reports both numbers, and it is easy to glance at them, register "higher is better," and move on. But cap rate and cash-on-cash return answer two different questions, and mixing them up leads to comparing deals that are not actually comparable — or to concluding that borrowing more is making you money when it is quietly costing you.

Cap rate: how good is the property, on its own

Cap rate is net operating income divided by purchase price. Net operating income — NOI — is rent minus operating expenses: taxes, insurance, maintenance, management, a capital reserve and an allowance for vacancy, but before the mortgage. That last part is the key. Cap rate has nothing to do with how you finance the deal. A cash buyer and a buyer putting 10% down calculate the identical cap rate on the identical property.

That makes it the right tool for comparing a duplex in one neighborhood against a single-family house in another, or for sanity-checking whether an asking price is in line with what similar properties trade for. It is a property-quality number, not a you-specific number.

It is also, read the other way round, a price. When people say a market "trades at a 6 cap," they are describing what buyers are currently willing to pay for a dollar of income there. A lower cap rate means buyers are paying more per dollar of income — usually because they expect rents or values to grow, or because they see the income as safer. A higher cap rate means they are paying less, which can mean a bargain or can mean the income is riskier than it looks. Cap rate on its own cannot tell you which, and that is worth remembering before treating a high one as a win.

Cash-on-cash return: how good is the deal, for you

Cash-on-cash return is annual pre-tax cash flow divided by the cash you actually put in — down payment, closing costs and any immediate repairs. Unlike cap rate, it depends entirely on financing. Change the down payment, the rate or the term and this number moves, while the property and its cap rate sit still.

Because the denominator is your own money rather than the purchase price, it answers a narrower and more personal question: how hard is the cash I committed actually working? That is the right question when you are deciding between this deal and some other use of the same money.

Side by side

Does borrowing more raise your return? Only sometimes

The common claim is that putting less down raises cash-on-cash return, because you are earning the same income on less of your own money. That is true only under a condition most people never state, and in the current rate environment the condition frequently fails.

The condition is this: borrowing raises your cash-on-cash return only when the loan costs less per year, per dollar borrowed, than the property earns per dollar of price. The property side of that comparison is the cap rate. The loan side is not the interest rate — it is the debt constant, which is the full annual payment divided by the loan amount. An amortizing loan repays principal as well as interest, so its constant is always higher than its rate.

Take a $275,000 property with $16,500 of net operating income — a 6.0% cap rate — and finance it two ways at the same 7.0% rate over thirty years, with $7,000 of closing costs in both cases. These figures are illustrative, not market data for any particular city.

More leverage made it worse, not better. At 7.0% over thirty years the debt constant is 7.98% — every dollar borrowed costs 7.98 cents a year to service, while every dollar of price earns 6.0 cents. Borrowing is buying income at a loss, and buying more of it loses more.

Run the same property across a range of rates and the switch is clean:

On this property the debt constant equals the 6.0% cap rate at an interest rate of about 4.39%. Below that, more leverage lifts cash-on-cash. Above it — which is to say, at every rate in the table — more leverage drags it down, and drags harder the more you borrow. The familiar advice that leverage amplifies returns is accurate but incomplete: it amplifies whichever direction the gap already points.

Why a high cash-on-cash number is not automatically good news

When the gap does favor borrowing, cash-on-cash rises as the down payment shrinks — and the number gets less informative as it climbs, because the denominator is shrinking faster than the numerator. A thin down payment means a larger loan, a larger payment, and less room between the rent and the bills. The same deal that reports an impressive return in a good year has the least margin when a tenant leaves or a rate resets.

Read it alongside the dollar figure rather than instead of it. A 12% return on $25,000 is $250 a month, and $250 a month is what has to absorb a water heater. The percentage describes the efficiency of your capital; the dollars describe whether the property can survive a bad quarter.

What neither number includes

Both metrics measure one year of operating performance, and a rental return has three other components neither one sees.

Principal paydown. Part of every mortgage payment reduces the loan balance. That is a real return — it just arrives as equity rather than cash — and it grows every year as more of the payment goes to principal. On a $206,250 loan at 7.0%, roughly $2,095 of principal is retired in the first year alone, which on $75,750 invested is about 2.8% a year that cash-on-cash does not count.

Appreciation. Neither metric assumes any. If the property gains value, that return is invisible here; if it loses value, so is the loss.

Tax treatment. Cash-on-cash is a pre-tax figure, and depreciation in particular can make the after-tax picture meaningfully different from the before-tax one. That is a question for an accountant rather than a calculator.

A deal showing 0.0% cash-on-cash is therefore not necessarily a deal returning nothing — but it is a deal returning nothing in cash, which is the part that pays for a new roof.

Using them together

The practical sequence is to use cap rate first and cash-on-cash second. Cap rate tells you whether the property is sensibly priced relative to its income and to comparable properties; it is the test the property either passes or fails regardless of who buys it. Only once the price makes sense is it worth asking how a particular financing structure makes it perform for your cash.

Doing it the other way round is how people talk themselves into overpaying: a low enough down payment can make almost any purchase price produce a respectable-looking percentage, right up until the gap between the cap rate and the debt constant turns against them.

Seeing it on a real property

The calculators on this site let you flip a property between Cash and Financed. Switch to Cash and cash-on-cash will change, sometimes sharply, while cap rate will not move at all — which is the whole distinction playing out on a number you chose rather than one in an article. The single-family rental analyzer reports both for a buy-and-hold house, and the multi-family calculator does the same for a small building, where the gap between cap rate and debt constant tends to be the difference between a deal and a near miss.