Margin analysis
Cap rate vs cash-on-cash: the two return numbers that actually matter
Two numbers get quoted as if they were interchangeable. They are not. One rates the building. The other rates your money. On the same property they can be a factor of ten apart, and knowing which one you are looking at is the difference between a deal and a story.
Ask an owner what their property returns and you will get a percentage. Ask which percentage and the conversation usually stops. There are two, they answer different questions, and the gap between them is entirely the work of your mortgage. Cap rate describes the asset as if you paid cash. Cash-on-cash describes what your actual dollars earn after the bank takes its cut. Confuse them and you will either reject a good deal or fall in love with a bad one.
Number oneCapitalization rate
The capitalization rate is the return the property produces on its own, before any financing enters the picture. It is net operating income divided by the price you pay.
That last point is the whole character of the number. The cap rate is deliberately blind to how you paid. According to the Corporate Finance Institute's valuation reference (corporatefinanceinstitute.com), the cap rate is found by "taking the net operating income of the property in question and dividing it by the market value of the property," and nowhere in it does a loan appear. Two investors buying the identical building at the identical price get the identical cap rate, whether one pays all cash and the other borrows ninety percent. It is a property number, not an investor number.
What NOI includes is where cap rates get quietly inflated or honestly stated. NOI is not gross rent. It is gross rent, minus vacancy, minus every recurring operating cost the building actually generates: taxes, insurance, management, utilities you cover, repairs, and a reserve for the capital items that wear out. According to the same Wikipedia reference (wikipedia.org), net operating income excludes depreciation and mortgage interest, and "Levered Pre-Tax Cash Flow = NOI - (Debt service)," which tells you plainly that debt service lives below the NOI line, not inside it.
Number twoCash-on-cash return
Cash-on-cash return is the one that answers the question you actually care about: what did the cash I put in earn this year? It is annual pre-tax cash flow divided by the cash you invested.
Unlike the cap rate, this number is built around your loan. According to the same reference (wikipedia.org), when an investor uses debt the mortgage payment is deducted from cash flow before the return is calculated, which is why financing can pull the number in either direction. Two investors buying the identical building at the identical price get two different cash-on-cash returns, because one borrowed more than the other. It is an investor number, not a property number.
The denominator matters as much as the numerator. Cash invested is not the purchase price. It is the slice of the price you funded yourself: the down payment, the closing costs, and the make-ready spend before a resident moves in. Leave any of those three out and the return you compute is fiction.
One property, both numbers
Formulas argue in the abstract. A single worked example settles it. Take one property and run both.
| Purchase price | $300,000 |
| Gross scheduled rent ($2,500/mo × 12) | $30,000 |
| Less vacancy at 5% | -$1,500 |
| Effective gross income | $28,500 |
| Less property tax | -$3,600 |
| Less insurance | -$1,200 |
| Less management at 8% of EGI | -$2,280 |
| Less repairs and maintenance | -$1,500 |
| Less capital expenditure reserve | -$1,500 |
| Net operating income | $18,420 |
The cap rate falls straight out of that last line:
Now add the loan. Put 25 percent down and borrow the rest at 7 percent over 30 years.
| Down payment (25% of $300,000) | $75,000 |
| Closing costs | $6,000 |
| Make-ready before first resident | $9,000 |
| Total cash invested | $90,000 |
| Loan amount ($225,000 at 7%, 30 yr) | |
| Annual debt service (principal + interest) | $17,963 |
| NOI | $18,420 |
| Less debt service | -$17,963 |
| Annual pre-tax cash flow | $457 |
Same building, same price, same day. The cap rate says 6.14 percent and the cash-on-cash says 0.51 percent. Neither is wrong. They are measuring different things, and the twelvefold gap between them is the mortgage, doing exactly what it does.
Why the two numbers split apart
The direction of the split has a name: leverage, positive or negative. The clean test is the loan constant, which is annual debt service divided by the loan balance. In the example that is $17,963 divided by $225,000, or 7.98 percent. Compare it to the 6.14 percent cap rate.
When the loan constant is higher than the cap rate, as it is here, every borrowed dollar earns less than it costs, so borrowing drags your cash-on-cash below the unlevered return. That is negative leverage, and at today's rates against modest cap rates it is common. When the loan constant is lower than the cap rate, borrowing lifts cash-on-cash above the cap rate, and leverage is working for you. Financing does not create return out of nothing. It amplifies the gap between what the property yields and what the debt costs, in whichever direction that gap runs.
For contrast, buy the same property with all cash. Total invested becomes $315,000 (price plus $6,000 closing plus $9,000 make-ready), there is no debt service, and annual cash flow is the full $18,420. Cash-on-cash is $18,420 divided by $315,000, or 5.85 percent, close to the cap rate and short of it only by the extra basis of closing and make-ready costs. With no loan, the two numbers nearly converge. The loan is the wedge.
Which number to use, and when
They are not rivals. They are tools for different jobs, and using the wrong one is how owners talk themselves into mistakes.
| Use cap rate when | Use cash-on-cash when |
|---|---|
| Comparing two properties as assets, stripped of how each buyer would finance them. | Deciding what your own dollars will actually earn this year, given your loan. |
| Backing into value: divide NOI by a market cap rate to estimate what a property is worth. | Comparing this deal against other places you could put the same cash, at the same risk. |
| Judging whether the operating income itself is strong, before the loan flatters or buries it. | Sizing a down payment: testing how the return moves as you put more or less cash in. |
A useful habit is to run both and then read the gap between them. A healthy cap rate with a punishing cash-on-cash is not a bad building; it is a financing problem you might fix with a larger down payment, a longer term, or a better rate. A thin cap rate propped into a decent cash-on-cash by heavy leverage is the opposite: the asset is weak and the debt is hiding it. The two numbers together tell you which conversation to have.
The mistakes that inflate both numbers
Most quoted returns are too high, and almost always for the same three reasons. Each one is a way of leaving a real cost out of the math.
Using gross rent instead of NOI. The single most common error, and the one that flatters cap rate the most. Gross scheduled rent divided by price is not a cap rate; it is a fantasy. In the example, $30,000 over $300,000 reads as a 10 percent cap rate. The real number, after vacancy and operating costs, is 6.14 percent. If someone quotes you a cap rate that looks too good, ask what they subtracted before they divided. Usually the answer is nothing.
Forgetting the capital expenditure reserve. Roofs, water heaters, HVAC and flooring do not bill monthly, so they get left out of NOI, and leaving them out lifts the cap rate on paper while guaranteeing a bill later. A reserve is not optional accounting; it is the annualized cost of the things that will certainly fail. In the example, dropping the $1,500 reserve alone would push the stated cap rate from 6.14 to 6.64 percent, a number that is half a point too generous every year until the water heater goes.
Ignoring vacancy. No rental collects twelve months of rent every year. Underwriting at 100 percent occupancy overstates income at the top of the cash flow, which inflates NOI, which inflates the cap rate, which then inflates the cash-on-cash beneath it. One optimistic assumption at the top corrupts both numbers at once. A vacancy allowance is not pessimism; it is the difference between scheduled rent and collected rent, and only collected rent pays anything.
The pattern underneath all three is the same one that governs rental margin generally: the costs that do not arrive as a monthly invoice are the costs owners forget, and the returns that forget them are the returns that disappoint. What you collect is not what you keep, and what a property yields on paper is not what it yields once every real cost is on the page.
A note on what we could not verify
We wanted to anchor this piece with a defensible "good cap rate" range and a typical cash-on-cash target, but the figures that circulate for both vary so widely by market, asset class and year that no single source we could stand behind offered a number worth publishing as a benchmark. Rather than quote a range we could not source cleanly, we left the thresholds out. The formulas, the worked example and the leverage test above are arithmetic and stand on their own; the market-average numbers were the part we would not print without a source we trusted.
Sources
- Capitalization rate reference, Wikipedia, wikipedia.org. Definition of cap rate as net operating income over current value; financing and depreciation ignored; NOI excludes debt service.
- Cash on cash return reference, Wikipedia, wikipedia.org. Definition as the ratio of annual before-tax cash flow to total cash invested; treatment of debt service in leveraged deals.
- Capitalization rate valuation reference, Corporate Finance Institute, corporatefinanceinstitute.com. Cap rate as net operating income divided by market value.