Free calculator
Rental cash flow calculator
See what a rental clears each month and year after the mortgage, operating costs, and set-asides for vacancy and repairs. The estimate is based on the numbers you enter.
The short answer
Last updated: July 2026
How do I calculate landlord cash flow?
Rental cash flow is what’s left after every cost: rent minus the mortgage, operating expenses (taxes, insurance, utilities, management), and set-asides for vacancy and maintenance. A positive number means the property pays you; a negative one means it costs you each month. This estimate uses the numbers you enter and excludes taxes and appreciation.
After the estimate:
Rent collection in AptoriaCash-flow calculator
What a rental clears each month.
Start from the rent, subtract the mortgage, operating costs, and set-asides for vacancy and repairs — and see the monthly and yearly cash flow.
Monthly rent
$
Monthly mortgage payment
$
Monthly operating expenses
$
Taxes, insurance, utilities, management, HOA — anything but the mortgage and the reserves below.
Vacancy allowance
5%
0%
20%
Maintenance / capex reserve
8%
0%
25%
Input-driven result
Your inputs
Formula
Result below
Monthly cash flow
$412
Rent $2,600 − mortgage $1,400 − opex $450 − vacancy $130 − reserve $208.
Annual cash flow
$4,944
Monthly cash flow × 12.
Monthly cash-flow composition
Rent
$2,600
Mortgage
-$1,400
Operating costs
-$450
Vacancy allowance
-$130
Reserve
-$208
Cash flow
$412
Estimate based on your inputs. Not a promise of results.
Estimate only. Vacancy and reserve are set-asides you budget as a share of rent, not bills you pay every month — actual costs vary. Excludes income taxes, appreciation, and loan principal paydown.
How it works
How this tool works.
Cash flow is the number that tells you whether a rental pays you or you pay it. The rent is only the starting point — the mortgage, the operating costs, and the money you should set aside for empty months and repairs all come out before anything lands in your pocket.
This calculator subtracts all of it: enter the rent, the mortgage, monthly operating expenses, and a percentage for vacancy and for a maintenance reserve, and it estimates your monthly and annual cash flow. It’s an illustration from your inputs — a negative result shows in red so a money-losing deal is obvious.
Make the result useful
Stress-test the monthly surplus
Monthly cash flow is most useful when every recurring owner cost is included: debt service, taxes, insurance, HOA, management, utilities, and a realistic maintenance allowance. A result that omits known costs is not conservative just because it is positive.
Then test a lower-rent or higher-expense month. The point is not to predict the future precisely; it is to learn how much room exists before a normal disruption turns the result negative.
Questions landlords ask
Questions about this tool and its limits.
Built by a landlord who's done every one of these jobs by hand.
Aptoria was built by an owner-operator managing a Brooklyn portfolio — the 11pm calls, the awkward rent texts, the April receipt-pile — not by a software team guessing at the problem.
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