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Rental property calculator
Price, loan, rent and expenses in, and the numbers that decide a rental out: monthly cash flow, cap rate, cash-on-cash return, DSCR and the 1 % rule.
Monthly cash flow after the mortgage
$0
$0 a year, before income tax.
| Rent collected (after vacancy) | $0 |
|---|---|
| Operating expenses | $0 |
| Net operating income (NOI) | $0 |
| Mortgage, principal and interest | $0 |
| Cash flow | $0 |
Loan and cash invested
| Loan amount | $0 |
|---|---|
| Monthly payment (P&I) | $0 |
| Cash invested | $0 |
| Gross rent multiplier | 0 |
Year-one numbers, before income tax and before loan principal you pay down. Rules of thumb vary by market: many small landlords look for a DSCR of 1.25 or more and positive cash flow with repairs budgeted.
How the calculator works
It follows the same order a lender or an experienced investor uses:
- Rent collected = monthly rent x 12, minus the vacancy share.
- Net operating income (NOI) = rent collected minus operating expenses (tax, insurance, HOA, utilities, repairs, big repairs, management). The mortgage is not an operating expense.
- Cash flow = NOI minus the mortgage payments (principal and interest).
From those three lines come the ratios:
| Ratio | Formula | What it tells you |
|---|---|---|
| Cap rate | NOI / price | The return of the property itself, as if you paid cash |
| Cash-on-cash | Cash flow / cash invested | What your own money earns each year |
| DSCR | NOI / loan payments | How safely the rent covers the loan |
| 1 % rule | Rent / (price + repairs) | A quick screen, not an answer |
The expenses people forget
- Big repairs. A roof, a water heater or an HVAC unit will need replacing. Setting aside 5 to 10 % of rent spreads that cost over the years.
- Vacancy. Even a good rental sits empty between tenants. 5 % is about 18 days a year; 8 % is about a month.
- Your time. If you manage it yourself, put 0 % for management, but remember the calls and the turnovers. A manager would charge 8 to 12 % of rent plus fees.
- Property tax after the sale. In many states the assessment resets when the property sells. Check the rate in property tax by state rather than the seller's bill.
Questions
What is a good cash flow for a rental property?
There is no single number, but many small landlords want positive cash flow after budgeting for repairs, big repairs and vacancy, not only after the mortgage. A property that only breaks even on paper often loses money in a year with a new roof or a long vacancy.
What expenses should I include?
Property tax, insurance, HOA dues, any utilities you pay, routine repairs, a reserve for big repairs such as a roof or HVAC, property management if you use it, and vacancy. Leave out the mortgage when you work out NOI; it comes off afterwards to get cash flow.
What is the 1 % rule?
A quick screen: monthly rent should be at least 1 % of the purchase price plus repairs. A $200,000 house would need $2,000 a month. It is a filter for which deals to look at, not a reason to buy. In expensive markets few properties pass it.
Does this include taxes on rental income?
No. The results are before income tax. Depreciation usually lowers the tax on rental income a lot; see the rental depreciation calculator for that part.
Why is cash flow different from profit?
Cash flow is the money left after all payments, including the principal part of your mortgage. Principal is not an expense: it builds equity. Depreciation is the opposite: an expense on your tax return that is not a payment. That is why cash flow, taxable profit and return on investment are three different numbers.
Sources
Next steps
Last updated November 5, 2026.