Rex says
Money math without the spreadsheet headache. Plug in your numbers and I'll show you exactly where the dollars land.
Try a scenario
Click to load — tweak from there.Inputs
Result
Monthly cash flow
-$4.00
Annual cash flow
-$48
Annual net operating income
$16,152
Monthly reserves set aside
$624.00
Operating expense ratio
43.9%
Debt service coverage ratio
1.00
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One click, a permanent link with your numbers baked in.
How to use this
- 1Enter monthly rent ($).
- 2Enter mortgage payment (p&i) ($).
- 3Enter property taxes per month ($).
- 4Enter insurance per month ($).
- 5Enter hoa per month ($).
- 6Enter vacancy reserve (%).
- 7Enter repairs reserve (%).
- 8Enter capex reserve (%).
- 9Enter property management (%).
- 10Read your monthly cash flow on the right — it updates as you type.
- 11Hit Share to keep the scenario or send it to someone.
About this calculator
Most first-time landlords forget the four reserves: vacancy, repairs, capital expenditure, and management. Skipping them turns a $250 'profit' into a loss the first time a water heater fails.
Worked example
Using the values the calculator loads with:
Inputs
- Monthly rent: 2400 $
- Mortgage payment (P&I): 1350 $
- Property taxes per month: 320 $
- Insurance per month: 110 $
- HOA per month: 0 $
- Vacancy reserve: 6 %
- Repairs reserve: 6 %
- CapEx reserve: 6 %
- Property management: 8 %
Results
- Monthly cash flow: -$4.00
- Annual cash flow: -$48.00
- Annual net operating income: $16,152.00
- Monthly reserves set aside: $624.00
- Operating expense ratio: 43.9%
- Debt service coverage ratio: 1
What each field means
Inputs
- Monthly rent ($)
- The monthly rent used in the calculation, measured in $. Starts at 2400 $ so you have a working example on load.
- Mortgage payment (P&I) ($)
- The mortgage payment (p&i) used in the calculation, measured in $. Starts at 1350 $ so you have a working example on load.
- Property taxes per month ($)
- The property taxes per month used in the calculation, measured in $. Starts at 320 $ so you have a working example on load.
- Insurance per month ($)
- The insurance per month used in the calculation, measured in $. Starts at 110 $ so you have a working example on load.
- HOA per month ($)
- The hoa per month used in the calculation, measured in $. Starts at 0 $ so you have a working example on load.
- Vacancy reserve (%)
- The vacancy reserve used in the calculation, measured in %. Starts at 6 % so you have a working example on load. Accepted range: 0–30 %.
- Repairs reserve (%)
- The repairs reserve used in the calculation, measured in %. Starts at 6 % so you have a working example on load. Accepted range: 0–30 %.
- CapEx reserve (%)
- The capex reserve used in the calculation, measured in %. Starts at 6 % so you have a working example on load. Accepted range: 0–30 %.
- Property management (%)
- The property management used in the calculation, measured in %. Starts at 8 % so you have a working example on load. Accepted range: 0–20 %.
Results
- Monthly cash flow
- Returned as a money amount in US dollars and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Annual cash flow
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Annual net operating income
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Monthly reserves set aside
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Operating expense ratio
- Returned as a percentage. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Debt service coverage ratio
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How does the rental property cash flow calculator work?
Most first-time landlords forget the four reserves: vacancy, repairs, capital expenditure, and management. Skipping them turns a $250 'profit' into a loss the first time a water heater fails. The underlying maths is: Cash flow = Rent − (mortgage + taxes + insurance + HOA + vacancy + repairs + capex + management).
What do I need to enter?
9 values: monthly rent, mortgage payment (p&i), property taxes per month, insurance per month, hoa per month, vacancy reserve, repairs reserve, capex reserve, and property management. Each field starts with a sensible default, so you can change one number at a time and watch the result move.
What does the monthly cash flow result mean?
It is returned as a money amount in US dollars and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds.
Is this calculator free, and do I need an account?
Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser.
How accurate is the result?
It applies the standard formula exactly, so the arithmetic is precise. Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
Who is this tool for?
It's built for anyone comparing money scenarios before committing — budgeting a payment, sanity-checking a quote, or seeing what a change in rate or term actually costs.
Accuracy and limitations
- Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
- Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.
- This is educational maths, not financial advice. Check anything contractual with the lender or your accountant.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Rental Property Cash Flow Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/rental-cash-flow
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/rental-cash-flow" target="_blank" rel="noopener">Rental Property Cash Flow Calculator — RevenueLab</a> (2026).</p>
Source: [Rental Property Cash Flow Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/rental-cash-flow) (2026).