Does cash flow include loan principal?

Yes. Debt service here is principal and interest. Cash flow shown is after P&I.

Do I include CapEx reserves?

Add them to operating expenses if you want a conservative view; otherwise NOI may be overstated.

Monthly or annual inputs?

Enter monthly amounts. We convert to annual for NOI and cash flow outputs.

NOI excludes financing. Cash flow subtracts debt service, so it reflects leverage impacts.

What about taxes on the cash flow?

Not included. Adjust separately for your tax situation with your CPA.

finance calculator

Rental Cash Flow Calculator

Calculate monthly and annual rental cash flow by accounting for vacancy, operating expenses, and debt service.

Results

Gross monthly income: $2,350
Vacancy loss (monthly): $118
Effective gross income (monthly): $2,233
Operating expenses (monthly): $600
NOI (monthly): $1,633
NOI (annual): $19,590
Debt service (monthly): $1,200
Cash flow (monthly): $433
Cash flow (annual): $5,190

How to use this calculator

Enter monthly rent and any other monthly income.
Set vacancy allowance and monthly operating expenses.
Enter monthly principal and interest (debt service).
Review gross income, EGI, NOI, and cash flow per month and per year.

Inputs explained

Monthly rent: Scheduled rent collected each month.
Other monthly income: Recurring add-ons: parking, storage, pet rent, RUBS, etc.
Vacancy allowance (%): Expected vacancy/credit loss percentage for the market/asset.
Operating expenses (monthly): Taxes, insurance, maintenance, repairs, management, and utilities you pay—exclude debt service.
Debt service (monthly): Monthly principal and interest on the loan (P&I only).

How it works

Gross income = Rent + other income. Vacancy loss reduces gross to effective gross income (EGI).

NOI = EGI − operating expenses (pre-financing). Cash flow = NOI − debt service.

Formula

Gross income = Rent + Other income
Vacancy loss = Gross income × Vacancy%
EGI = Gross income − Vacancy loss
NOI = EGI − Operating expenses
Cash flow = NOI − Debt service

When to use it

Quickly underwriting rentals to see monthly/annual cash flow before offers.
Testing sensitivity to vacancy, expenses, or new financing terms.
Feeding cash flow into cap rate, DSCR, or cash-on-cash analyses.

Tips & cautions

Use realistic vacancy and fully loaded expenses (management, maintenance, reserves) to avoid overstating cash flow.
Debt service should match your current or proposed loan terms; adjust when rates or amortization change.
For seasonal or variable income, use an average month to avoid overestimating cash flow.
Does not include CapEx reserves unless you add them to operating expenses.
Ignores income taxes; for after-tax cash flow, adjust separately.
Single monthly snapshot—does not model rent growth or expense inflation over time.

Worked examples

$2,200 rent, $150 other, 5% vacancy, $600 opex, $1,200 debt

Gross = $2,350; Vacancy loss = $117.50; EGI ≈ $2,232.50
NOI ≈ $1,632.50/mo ($19,590/yr)
Cash flow ≈ $432.50/mo ($5,190/yr)

$1,800 rent, $0 other, 8% vacancy, $550 opex, $900 debt

Gross = $1,800; Vacancy loss = $144; EGI = $1,656
NOI = $1,106/mo ($13,272/yr)
Cash flow = $206/mo ($2,472/yr)

Deep dive

This rental cash flow calculator subtracts vacancy, expenses, and debt service from rent and other income to show NOI and net cash flow per month and per year.

Use it for fast underwriting before offers, then plug results into cap rate, DSCR, or cash-on-cash return to complete your analysis.

FAQs

Does cash flow include loan principal?: Yes. Debt service here is principal and interest. Cash flow shown is after P&I.
Do I include CapEx reserves?: Add them to operating expenses if you want a conservative view; otherwise NOI may be overstated.
Monthly or annual inputs?: Enter monthly amounts. We convert to annual for NOI and cash flow outputs.
Cash flow vs NOI?: NOI excludes financing. Cash flow subtracts debt service, so it reflects leverage impacts.
What about taxes on the cash flow?: Not included. Adjust separately for your tax situation with your CPA.

Related calculators

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Net Operating Income (NOI) Calculator

Compute NOI by subtracting vacancy and operating expenses from gross income for clear property underwriting.

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Cap Rate Calculator

Calculate rental property cap rate from NOI and property value for quick deal screening.

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DSCR Calculator

Calculate debt service coverage ratio (DSCR) from NOI and annual debt service to check lender thresholds.

For underwriting estimates only. Confirm rents, expenses, vacancy, and loan terms before making investment decisions.