Cash-on-Cash Return for an STR
Cash-on-cash return is the cleanest answer to "what is my actual cash earning?" — but only if you count all the cash you put in. Most STR buyers divide by the down payment and quietly forget the furnishing, the closing costs, and the setup, which makes every deal look better than it is. Here's how to compute it honestly, and what it can and can't tell you.
Matt NunnFounder, Builders Finance10 min readOn this page6 sections
- What cash-on-cash actually measures
- The numerator: honest cash flow, nothing borrowed from optimism
- The denominator: count every dollar, not just the down payment
- What this does to the canonical deal
- What cash-on-cash tells you — and what it doesn't
- The Builders Finance Underwriting Method
- Your action plan
- The bottom line
Key takeaways
- Cash-on-cash return is one fraction: annual pre-tax cash flow ÷ total cash invested. It's the yield your actual out-of-pocket cash is earning this year — nothing more, nothing less.
- The numerator is the honest cash flow from the last three guides. The denominator is where the metric is most often distorted — usually by counting only the down payment and forgetting everything else it took to open the doors.
- For a short-term rental, "everything else" is large: closing costs, and especially furnishing and setup — the $30–50k a long-term rental never spends. Leave it out and your return looks double what it is.
- Cash-on-cash is a single-year snapshot. Use year one to see your liquidity and startup risk — the setup capital is real and the ramp is real — and use a stabilized year to judge the property's long-term earning power. Read both, not just one.
- It's a cash yield, so it's blind on purpose to appreciation, loan paydown, and taxes. It answers one question well; it is not your total return, and it is not the same number as cap rate.
What cash-on-cash actually measures
It's the yield on the cash you actually put in. The whole metric is one honest fraction:
Cash-on-cash return = annual pre-tax cash flow ÷ total cash invested
Cash-on-cash isn't trying to predict your wealth. It's answering a much narrower question — what cash yield did this deal produce on the cash I actually put in this year? — and its usefulness comes entirely from staying inside that question.
The numerator is what the property puts in your pocket in a year after the mortgage is paid — your pre-tax cash flow, the last number from the cash-flow guide. The denominator is every dollar of your own money it took to get the property earning. Divide one by the other and you get a percentage you can read like any yield: this is what my cash is earning this year.
That "after the mortgage" part is what makes cash-on-cash different from cap rate, and the difference matters enough to name now. Cap rate measures the property (NOI ÷ price) as if you'd paid cash — it ignores your loan entirely. Cash-on-cash measures you: your cash flow after debt service, over your actual cash in. Put it in one line: cap rate evaluates the property; cash-on-cash evaluates your investment in that property. Same deal, two very different numbers. Start both from the same operating NOI: cap rate stops there, while cash-on-cash carries on — subtracting debt service and dividing by the cash you actually invested. The distance between them is what financing and your capital structure did to your return. (The full comparison, and when each one misleads, is the cap-rate guide.)
The numerator: honest cash flow, nothing borrowed from optimism
Whatever's wrong with your cash flow is wrong with your return. The numerator is pre-tax cash flow — revenue, minus operating expenses, minus debt service — and it's only as honest as the revenue and cost work behind it. If the revenue line was a raw comp and the cost stack was missing half its lines, the cash flow is inflated and so is every return you compute from it. There's nothing new to do here; it's the reminder that cash-on-cash inherits the honesty of the numbers above it. (Getting that number right is the revenue guide, the cost guide, and the cash-flow guide.)
The denominator: count every dollar, not just the down payment
This is where the metric is won or lost. Total cash invested is all the money that left your accounts to get this property open — and for a short-term rental it is a stack, not a single line:
| Cash you put in | Canonical $650k example | Usually forgotten? |
|---|---|---|
| Down payment | $162,500 (25%) | No — everyone counts this |
| Closing costs | ~$19,500 (~3%) | Often |
| Furnishing & setup | $45,000 | Almost always |
| Operating reserve / working capital | committed floor only (see below) | Almost always |
| Total cash invested | $227,000 | — |
The down payment is the one number nobody forgets — and on its own it's barely half the real figure. Closing costs are a few percent of price. And furnishing and setup are the line that separates STR math from long-term-rental math entirely: a short-term rental has to be fully furnished, equipped, photographed, and stocked before it earns a dollar, and on a house like this that's tens of thousands of dollars of your own cash. Divide by the down payment alone and you haven't computed a return — you've computed a fantasy with the same units.
Two honest wrinkles. First, the reserve: if you're permanently setting aside a cash buffer as the property's working-capital floor, that's committed capital and it belongs in the denominator; if it's just personal savings you keep liquid and might spend on anything, leave it out. Second, financing the furniture doesn't make it free. Pay cash and the $45,000 sits in the denominator; put it on a furniture loan or a card and it moves to the numerator instead — a new debt-service line that lowers your cash flow. Either way you paid for it. Financing only shifts the weight from one half of the fraction to the other; it never removes it, and a return that looks better only because the furniture is off the balance sheet isn't better.
What this does to the canonical deal
The naive and honest returns aren't a little apart — they're on opposite sides of "worth doing." Take the $650,000 vacation home again. Underwritten naively, the buyer sees about $30,100 of cash flow on $162,500 of cash in — the down payment — for a cash-on-cash return of 18.5%. Underwritten honestly, the cash flow is about $100 and the cash in is $227,000 once closing and the $45,000 of furnishing are counted, for a cash-on-cash return of roughly 0%.
Look at what moved. The numerator collapsed (honest revenue and a full cost stack took $30,100 down to ~$100), and the denominator grew by nearly $65,000 (the money the naive version pretended it never spent). Cash-on-cash was distorted from both ends at once — which is exactly why it's such a useful discipline: it forces an honest numerator and an honest denominator in the same breath, and a deal can't hide in either one.
What cash-on-cash tells you — and what it doesn't
It answers one question cleanly, and stays silent on three others. Cash-on-cash is a genuine cash yield, which makes it good for the thing yields are good for: comparing the cash efficiency of one deal against another on the same honest basis, or against whatever alternative you'd otherwise do with the money. Used that way it's one of the most practical numbers in underwriting.
But it is deliberately blind to three things, and reading it as if it weren't is the trap. It ignores appreciation and loan paydown — real components of return that simply aren't cash in your pocket this year. It ignores taxes — depreciation and deductions can change your after-tax result meaningfully, and how they apply depends on your situation and belongs with your own qualified tax professional. And it ignores time: cash-on-cash is a single-year snapshot, and for an STR the first year is often the weakest it will post — the setup capital is fully spent while operations are still stabilizing. A deal that reads ~0% in year one can look materially different once it stabilizes. So compute it both ways — year one to size the liquidity and startup risk you're taking on, a stabilized year to judge the property's long-term earning power — and read it as one honest yield among several measures, not as the whole verdict.
The Builders Finance Underwriting Method
Source it — trace every number to real evidence, not a headline. Haircut it — discount for the year you'll actually have; round revenue down, costs up. Record it — write down the value, its source, and the haircut you applied. Stress it — move the numbers that matter to their downside before you trust them.
A return means nothing until every dollar you put in is in the denominator.
The easiest way to make a bad deal look good is to divide real cash flow by a fraction of the real cash invested. Count the down payment, the closing costs, the furnishing, and the setup — all of it — before you take the return seriously. A return computed against the down payment alone isn't optimistic; it's measuring the wrong thing.
Dividing by the down payment. It's the most natural error in real-estate math because the down payment is the one big check you consciously write — so it feels like "the money you put in." But the closing costs cleared your account too, and the $45,000 of furniture is sitting in the house. Counting only the down payment doesn't just nudge the return up; on a fully-furnished STR it can materially overstate it, turning a flat deal into an apparently great one. If a return looks strong, check the denominator before you believe it.
Your action plan
- Start with honest cash flow. Use your stabilized pre-tax cash flow — revenue net of fees, full cost stack, debt service — not a naive or year-one figure.
- Build the full denominator. Down payment + closing costs + furnishing and setup + any reserve you're funding. Every dollar that left your accounts to open the doors.
- Divide, and label it. Cash flow ÷ total cash invested. Write the percentage next to the two numbers that made it, so the inputs travel with the result.
- Do it twice — year one and stabilized. Year one carries the setup drag; the stabilized year shows what the deal actually yields. Judge on the second.
- Compare on the same basis. When you stack this deal against another (or against an alternative use of the cash), make sure both were computed with the full denominator — otherwise you're comparing an honest number to a flattering one.
- Remember what it leaves out. Before you decide, add back the context cash-on-cash ignores — appreciation, paydown, and (with your tax professional) tax treatment — rather than letting one yield stand in for total return.
The bottom line
Cash-on-cash return is the most useful one-line answer to "is my money working?" — but only when both halves of the fraction are honest. The numerator borrows its integrity from your revenue and cost work; the denominator is yours to get right, and getting it right means counting the furnishing and the closing and the setup alongside the down payment. Do that, compute it for a stabilized year, and read it for what it is — a clean cash yield, not the whole story of the deal — and you'll have a number you can actually compare and actually trust. Divide by the down payment alone and you'll have a number that flatters every deal equally, which is the same as telling you nothing.
Educational information only — not individualized tax, legal, or investment advice. The worked example is an illustrative model, not a projection or a recommendation.
