Cash-on-Cash Return: The Rental Investor Metric That Matters

I was staring at a listing and my spreadsheet was lying to me

I was sitting in my truck outside a duplex showing, phone calculator open, and I kept getting two totally different “returns” depending on which tab I looked at. One number said the deal was fine. The other number said I was basically working for free. And the thing is… both numbers were technically correct.

That’s when cash-on-cash return finally clicked for me.

Not because it’s fancy. It’s not. It’s because it answers the question you actually care about this week: “If I wire my down payment and closing costs, what do I get back in cash each year?” Not appreciation. Not vibes. Cash back to you.

Cash-on-cash is just your yearly cash flow divided by your cash invested

You’ll hear people toss around cap rate like it’s the only metric that matters, and I mean, cap rate is useful. But cap rate ignores financing. If you’re buying with a loan (you are), you can have a decent cap rate and still have crummy cash flow because the mortgage payment eats everything.

So why does everyone get this wrong? Because they mix up “profit on paper” with “money that lands in your account.” Cash-on-cash doesn’t let you hide from that.

And yes, people argue about what counts as “cash invested.” I’ve done it too. Some folks include reserves, some don’t. I usually track it both ways, because the bank-required reserves still tie up your money even if you don’t “spend” it (and your opportunity cost doesn’t care what you call it).

Here’s a quick cheat table I wish someone handed me earlier.

So. If you only remember one thing: cash-on-cash is a financing-and-cash metric, not a property-only metric.

Run it on a real deal (the kind you’re probably looking at)

Let’s do a worked example with numbers that look like actual listings, not a unicorn spreadsheet. Say you’re buying a small single-family rental for 310,000. It’s renting (or will rent) for about 2,450 per month. You’re putting 25% down, and you’re not doing a full rehab, but you do need 6,000 in immediate fixes because the inspector found a handful of “not today, Satan” items.

And you’re seeing a cap rate around 6.2% on the broker’s sheet. Cool. We’ll still compute cash-on-cash, because the broker’s cap rate doesn’t pay your mortgage.

Step 1: Estimate annual income.
Gross scheduled rent: 2,450 × 12 = 29,400.

Step 2: Subtract vacancy and credit loss.
I usually plug 5% if the area is stable and the property isn’t a headache. So vacancy: 29,400 × 0.05 = 1,470.
Effective gross income: 29,400 − 1,470 = 27,930.

Step 3: Subtract operating expenses (not the mortgage).
This is where people get… optimistic. I’ll throw out a realistic set:

• Property taxes: about 4,800/year (your county will decide your fate here)
• Insurance: about 1,600/year
• Property management: 8% of collected rent → 27,930 × 0.08 = 2,234 (even if you self-manage, price your time somehow)
• Repairs & maintenance reserve: 1,200/year
• Capex reserve: 1,800/year (roof/HVAC/water heater… the usual villains)
• Landscaping/HOA/misc: 600/year

Total operating expenses: 4,800 + 1,600 + 2,234 + 1,200 + 1,800 + 600 = 12,234.

NOI (Net Operating Income) = 27,930 − 12,234 = 15,696.

Now, if you want a quick cap rate check: 15,696 ÷ 310,000 = about 5.1%. Notice how that’s already different than the “around 6.2%” someone printed on a flyer. That happens all the time because their expense assumptions are… creative.

Step 4: Subtract annual debt service.
Loan amount: 310,000 × 0.75 = 232,500.
Let’s say the principal + interest payment comes out around 1,520/month (rate-dependent, obviously), so annual debt service: 1,520 × 12 = 18,240.

Annual pre-tax cash flow = NOI − debt service = 15,696 − 18,240 = −2,544.

Yeah. Negative cash flow. That’s not a typo.

Step 5: Total cash invested.
Down payment: 77,500.
Closing costs (say 3% ballpark): 9,300.
Immediate repairs: 6,000.
Total cash invested: 92,800.

Cash-on-cash return = (−2,544 ÷ 92,800) × 100 = about −2.7%.

And that’s the moment you stop saying “but the cap rate is decent” and start saying “this deal doesn’t pay me.” (Unless you’re betting on rent growth, or you’re doing a value-add plan you actually understand, or you’re in a market where you’re intentionally buying negative cash flow for some other reason. But at least you’ll be doing it with your eyes open.)

So what would make it work? Higher rent, lower price, lower rate, bigger down payment (sometimes), or lower expenses. Or some combo. Cash-on-cash forces you to pick which lever you’re pulling instead of pretending they don’t exist.

What I look for (and what I don’t trust) when someone throws out a cash-on-cash number

I’ve analyzed enough rentals to know the “return” number is usually where the sales pitch lives. So I sanity-check it the same way every time, kind of like tapping on drywall to find a bad patch.

1) Did they include vacancy?
If the pro forma assumes 0% vacancy, that’s not underwriting, that’s wishful thinking. Even great tenants move. Even great markets have turnover.

2) Did they bake in repairs and capex?
This is the classic trick: they’ll show “cash flow” that’s really just “cash flow until the first big thing breaks.” If you’re not reserving something, your cash-on-cash is inflated. Period.

3) Are they using today’s taxes and insurance?
Taxes can reset after purchase in some areas. Insurance has been jumpy in a lot of places lately. If you underwrite with last year’s numbers and they jump 20–40%, your return evaporates. I’ve watched it happen.

4) Are they counting only the down payment as cash invested?
Closing costs matter. Rehab matters. Buying points matters. If you wrote the check, it’s cash invested. Otherwise you’re grading yourself on a curve you invented.

5) Are they mixing cash-on-cash with total return?
Total return can include principal paydown and appreciation. That’s fine to track. But it’s not the same thing as cash-on-cash. If someone says “cash-on-cash is 12%” and then they quietly included appreciation, they’re not talking about cash-on-cash anymore, they’re talking about a story.

And yeah, I still like cap rate. I still look at IRR on bigger deals. But for a normal rental investor deciding whether to buy a property this week, cash-on-cash is the gut check.

Calculators I actually use while underwriting (so you don’t have to rebuild my spreadsheet)

I built these because I got tired of retyping the same math and second-guessing myself at 11:30 pm.

(If you’re the kind of person who likes to click buttons before you commit to a spreadsheet, I get it. I am also that person.)

FAQ (the stuff people text me after they run the numbers)