Ask two investors about the same rental and one quotes the cap rate while the other quotes cash-on-cash — and they reach opposite conclusions. Both numbers are legitimate; they answer different questions. The mistakes happen when either is asked to do the other's job. Here is what each measures, the same deal run both ways, and an honest verdict on which should decide.
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What each number measures
Cap rate measures the property, ignoring financing:
It answers: "What does this asset earn from operations, relative to its price, if bought with cash?" Because it strips out the loan, cap rate is the cleanest way to compare two properties, two neighborhoods, or a property against its local market.
Cash-on-cash return measures your cash, with your financing:
It answers: "What is the money I actually put in earning me each year?" Change the down payment or the interest rate and cash-on-cash moves — even though the property hasn't changed at all.
| Cap rate | Cash-on-cash | |
|---|---|---|
| Measures | The property | Your cash, with your loan |
| Includes your financing? | — No | ✓ Yes |
| Use it to | Compare properties and markets | Judge the deal you're signing |
| Same for every investor? | ✓ Yes | — No, it depends on your terms |
| On the sample deal | 5.0% | −6.4% |
The same deal, both ways
Our standard sample: price $250,000, rent $1,800/month, NOI $12,432, bought with 20% down and a $200,000 loan at 7% / 30 years, about $55,200 total cash in.
Cash-on-cash: ($12,432 − $15,967) ÷ $55,200 = −$3,535 ÷ $55,200 ≈ −6.4%
A 5.0% cap rate and a −6.4% cash-on-cash on the same property in the same year. Neither is a typo. The gap between them is the financing: debt service of $15,967/year exceeds NOI of $12,432, so the leveraged position loses cash even though the underlying asset earns a positive operating return.
The mechanism is worth naming. When the cap rate is below the interest rate on the loan (5.0% vs 7% here), leverage is negative — borrowing makes your return worse than paying cash. When the cap rate is above the borrowing cost, leverage works the other way and cash-on-cash exceeds the cap rate, sometimes dramatically. Same property, same NOI — the spread between the two rates decides which world you're in.
When cap rate misleads
- As a personal return forecast. Cap rate knows nothing about your 7% loan. Quoting it as "my return" overstates a financed deal whenever debt costs more than the cap rate — and hides the loss entirely in a case like the sample.
- Across different risk profiles. A 7% cap rate on a tired property in a shrinking town is not better than 5% on a sound one; the higher number is partly compensation for risk and future CapEx.
- When NOI is optimistic. Cap rate inherits every sin in the NOI beneath it — 0% vacancy, no CapEx reserve, seller-supplied expenses. Garbage NOI, garbage cap rate.
When cash-on-cash misleads
- When comparing properties. Because it bakes in your loan terms, two investors compute different cash-on-cash for the same house. It cannot rank properties; it ranks property-plus-financing packages.
- When leverage is maxed to flatter it. A tiny down payment can manufacture a dazzling cash-on-cash on a fragile deal — while DSCR sits near 1.0 and one vacancy erases the year. (In the sample, DSCR is 0.78: the property doesn't even cover its own debt.)
- Across time. Cash-on-cash is a year-one snapshot. It says nothing about equity build-up, appreciation, or how the deal seasons — which is what multi-year projections are for.
The honest verdict
Use them in sequence, not in competition:
- Cap rate screens the asset. Is this property's operating return sensible for its market and condition, on honestly-built NOI? If the asset itself is weak, no financing structure redeems it.
- Cash-on-cash judges the deal you're actually signing — with your down payment, your rate, your closing costs. This is the return on the check you write.
- DSCR and cash flow stand guard. If the property can't cover its debt service with a margin, the other two numbers are academic.
And if forced to pick one number to decide with? The one that includes the financing you're really taking on — cash flow and cash-on-cash — because that is the deal that will actually happen to you. Cap rate tells you whether the property deserved a closer look. It should never be the number that talks you into writing the check. In our sample, cap rate says "mediocre asset"; cash-on-cash says "and the financing makes it a loser." The deal fails — and you needed both numbers, in that order, to see the whole of why.
Common mistakes
- Comparing one deal's cap rate to another's cash-on-cash. Apples, meet oranges.
- Quoting cap rate as your return on a financed purchase — the single most common version of this error.
- Optimizing cash-on-cash with maximum leverage while ignoring DSCR and reserves.
- Building either number on flattering NOI — no vacancy, no CapEx reserve, seller's expense figures. Both metrics are only as honest as the NOI underneath.
Both numbers, one sheet
Our Real Estate Deal Analyzer puts cap rate and cash-on-cash side by side on the same honestly-built NOI — CapEx reserve included as its own line — plus DSCR, so the guard metrics are never an afterthought. The free Lite version covers the core sheet; the Full version adds sensitivity analysis, a 5-year projection with IRR, BRRRR and a 3-deal comparison for when the screening says "maybe." Start free on the Real Estate Deal Analyzer page.
Lite first, free — both numbers on the same NOI, side by side.
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This guide is an educational calculation aid, not financial, tax, or legal advice. Verify all figures against local data and consult licensed professionals before purchasing any property.