How rental property ROI is calculated

The return in one paragraph

A rental return is not the rent and it is not the appreciation. Cash flow is what is left of the rent after vacancy, the mortgage, and the operating bills you type. Cash-on-cash divides a year of that cash flow by the cash you put in, which this model treats as the down payment. Cap rate ignores the loan and divides net operating income by the purchase price, so two buildings can be compared before financing. The rental property ROI calculator runs those three readings, then projects the same annual cash flow across the hold, with the property value and the loan balance moving underneath. The result is an educational estimate. It is not an appraisal, a lender quote, or a tax return.

When to use

Use this guide when you are sketching a buy-and-hold and you want the rent, the debt, and the operating costs in one place before you treat “it cash flows” as a return. It fits a first pass on a listing, a comparison of two rents, or a check of how thin the monthly surplus is once vacancy and management are in the bill. Change one input at a time. Scenario B exists so a lower price or a different rent does not overwrite the first sketch.

It does not fit a buy-rehab-sell. A flip’s profit is a single exit, not a multi-year rent roll. That question belongs on the house flip calculator. It also does not answer “rent this life or buy the home I will live in.” The rent versus buy guide compares the cost of staying, which is a household question rather than an investment yield. Extra principal on a loan you already have is the mortgage payoff calculator.

The formula in plain English

The calculator uses the same identities on every run:

Down payment = purchase × down payment percent
Loan = purchase − down payment
Effective rent = gross rent × (1 − vacancy percent)
Operating expenses = tax/12 + insurance/12 + HOA + rent × maintenance + rent × management
Monthly cash flow = effective rent − mortgage − operating expenses
Cash-on-cash = (monthly cash flow × 12) / down payment
NOI = (effective rent − operating expenses) × 12
Cap rate = NOI / purchase price
Value in year t = purchase × (1 + appreciation)^t

The mortgage payment is the standard fixed-rate formula on the loan amount, the annual rate divided by 12, and the term in months. Maintenance and management are percents of gross rent, not of effective rent, so a vacancy assumption does not quietly shrink those bills. Cash flow is held flat for every year of the hold. Rents do not inflate, and neither do taxes or insurance. Appreciation changes the property value and therefore the equity column. It does not become cash until you imagine a sale the model does not run. Equity is that value minus the remaining loan balance. Nothing you type is sent to a server to compute the result.

A worked example

Use the sketch the calculator opens with. Hold is 15 years. Appreciation is 3% a year. HOA is zero.

The cap rate can look acceptable while the cash-on-cash is almost nothing. That split is the point of reading both numbers. The equity is mostly the paydown of the loan plus the appreciation assumption, not money that arrived as rent. Rerun the sketch in the rental property ROI calculator. Put this case in one scenario and a lower price, or a higher rent, in the other.

How to read the result

Monthly cash flow is the surplus or the shortage after the bills in the formula. A positive number of a few dozen currency units is a thin deal: one month of vacancy above the assumption, or one repair, can erase a year of it. Cash-on-cash uses that surplus and the down payment only. Closing costs and a cash reserve are not in the denominator. Cap rate is the unlevered reading. A higher cap rate with a worse cash flow usually means the financing, not the building, is the part that turned the deal tight.

The year table does not raise the rent. If you need inflation, that is a different model. The inflation guide is about purchasing power, not about indexing a lease. Equity is not spendable cash. Selling costs, tax on a gain, and a prepayment on the loan are outside this page.

Common mistakes

Calling the rent the return. Gross rent of 2,800 becomes 2,660 after a 5% vacancy, then about 26 after the mortgage and the operating bills. The first number is not the yield.

Using zero vacancy because the unit is full today. The percent is a planning assumption. A full building can still go empty. Maintenance and management stay tied to gross rent even when you raise vacancy, so the cash flow falls by the whole lost rent.

Treating appreciation as cash-on-cash. The 3% in the example lifts the year-15 value. It does not lift the 315 of annual cash flow. Cash-on-cash stays the operating surplus divided by the down payment.

Leaving closing costs and reserves out of “cash invested,” then comparing the result with a deal that included them. This version’s denominator is the down payment. Add those costs yourself if you want a stricter yield.

Forgetting that the cash flow does not inflate and the mortgage does not recast. A fixed payment against a flat rent is the sketch. A real lease and a real tax bill move. The page is for seeing the structure, not for promising the year-15 surplus.

FAQ

What is the difference between cash-on-cash and cap rate?

Cash-on-cash divides annual cash flow, after the mortgage, by the down payment. Cap rate divides net operating income, before the mortgage, by the purchase price. One tells you what the cash you invested is producing. The other compares the building before you choose a loan.

Does this include income tax or depreciation?

No. Results are pre-tax. Depreciation, deductible interest, and your filing status can change the after-tax result. This guide does not estimate that.

Why is cash flow flat for the whole hold?

The model repeats the first year’s cash flow. Rent, tax, insurance, maintenance, and management do not inflate. Appreciation affects value and equity only. That keeps the operating sketch readable. It is not a forecast that expenses stay still.

Are closing costs in the cash invested?

No. Cash invested for cash-on-cash is the down payment. If you want those costs in the denominator, add them to the cash you think of as invested. The calculator will not do that for you.

Is this financial advice?

No. FinTools4U guides and calculators are for education. They do not replace rent comps, an inspection, a lender quote, or advice about your tax situation.

Related guides

• How house flip profit is calculated — a single exit after rehab and selling costs, instead of a multi-year rent roll.
• How rent versus buy is calculated — the cost of renting or owning the home you live in, which is not this yield.
• How a mortgage payment is calculated — the principal-and-interest payment inside the cash-flow line, with tax and insurance called out on their own.
• How extra mortgage payments change the payoff — what happens if you send principal above the rental’s scheduled payment.

Try it with your figures

Open the rental property ROI calculator and enter the purchase, the down payment, the rent, and the bills you would actually pay. Read cash flow, cash-on-cash, and cap rate before you read the year-15 equity. Share the URL if you want the same inputs again — the numbers stay in the link, not on a server.