Rental Property Cash Flow Calculator

Use monthly rent, realistic vacancy, operating reserves, and the actual financing you expect. Results are pre-tax planning estimates, not legal, tax, or investment advice.

Deal profile:

Choose a buy-and-hold starting pattern or keep Custom after editing.

Currency symbol:

Use $, EUR, GBP, RM, or another short symbol for your underwriting sheet.

Purchase price:

Enter the contract price or all-in acquisition price before closing costs and repairs.

Monthly rent:

Gross scheduled rent before vacancy, management, and reserves.

{{ currencyLabel }} / mo

Vacancy allowance: {{ formatPercent(vacancy_rate, 1) }}

Use a conservative local vacancy and turnover assumption.

Down payment: {{ formatPercent(down_payment_pct, 1) }}

Investment property loans often need more equity than owner-occupied loans.

Interest rate: {{ formatPercent(interest_rate, 2) }}

Use the investment-property note rate you can actually secure.

% / yr

Loan term:

Use 0 when modeling an all-cash purchase.

yrs

Property tax:

Annual tax estimate from the county, reassessment, or broker package.

{{ currencyLabel }} / yr

Insurance:

Use the landlord policy quote, not owner-occupied insurance unless that is the actual policy.

{{ currencyLabel }} / yr

HOA or fixed dues:

Use 0 if there are no recurring association dues.

{{ currencyLabel }} / mo

Maintenance reserve: {{ formatPercent(maintenance_pct, 1) }} of rent

Keeps routine repairs from overstating cash flow.

Management fee: {{ formatPercent(management_fee_pct, 1) }}

Use 0 for self-management only when you are deliberately valuing your own time elsewhere.

CapEx reserve: {{ formatPercent(capex_pct, 1) }} of rent

Model reserves separately so NOI is not inflated by deferred replacements.

Closing costs: {{ formatPercent(closing_cost_pct, 1) }}

Add lender, title, transfer, inspection, and acquisition fees paid out of pocket.

Initial repairs or rehab:

Use 0 for a stabilized turnkey property.

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Other monthly income:

Include only predictable recurring income.

{{ currencyLabel }} / mo

Owner-paid utilities:

Use monthly owner-paid utilities not reimbursed by tenants.

{{ currencyLabel }} / mo

Other operating expenses:

Keep debt payments out of this line so NOI remains property-level.

{{ currencyLabel }} / mo

Initial cash reserve:

Use 0 if reserves are tracked outside the acquisition cash stack.

Target cash-on-cash: {{ formatPercent(target_coc_pct, 1) }}

Set the yearly return target for your cash invested.

Target DSCR: {{ formatRatio(target_dscr) }}

Common lending screens often focus around 1.20 to 1.25, but requirements vary.

Stress rent change: -{{ formatPercent(stress_rent_drop_pct, 1) }}

Use 5-15% when testing soft rent comps.

Stress vacancy add-on: +{{ formatPercent(stress_vacancy_add_pct, 1) }}

Vacancy stress tests downtime, turnover, and slower collections.

Stress expense add-on: +{{ formatPercent(stress_expense_add_pct, 1) }}

Models insurance, repairs, tax, utility, or management cost pressure.

Stress rate add-on: +{{ formatPercent(stress_rate_add_pct, 2) }}

Use 0 if the loan rate is fixed and locked.

Money precision:

Whole units are usually best for an investor memo.

Metric	Value	Planning note	Copy
{{ row.metric }}	{{ row.value }}	{{ row.note }}

Line item	Monthly	Annual	Treatment	Copy
{{ row.item }}	{{ row.monthly }}	{{ row.annual }}	{{ row.treatment }}

Scenario	Cash flow	DSCR	Cash-on-cash	Signal	Copy
{{ row.scenario }}	{{ row.cashFlow }}	{{ row.dscr }}	{{ row.coc }}	{{ row.signal }}

Target	Required rent	Meaning	Copy
{{ row.target }}	{{ row.requiredRent }}	{{ row.meaning }}

{{ formattedJson }}

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A rental property's monthly rent is only the top line. The investment result depends on how much income survives vacancy, taxes, insurance, association dues, management, repairs, long-cycle reserves, and any loan payment. Cash flow puts those pieces into one pre-tax monthly result, which shows whether the property is expected to send money to the owner or require support from other income.

The strongest rental analyses keep property economics separate from investor financing. Net operating income, usually shortened to NOI, measures income after vacancy and operating expenses but before debt service. Cap rate compares annual NOI with the purchase price, so it can compare properties without letting loan terms hide the operating performance. Cash-on-cash return starts after debt service and divides annual cash flow by the cash invested, so it changes when the down payment, closing costs, initial repairs, or reserve cash changes.

Debt service coverage ratio, or DSCR, adds a lender-style coverage check. A property can show positive cash flow but still miss a DSCR target if the NOI cushion above the loan payment is too thin. The reverse can also happen in an all-cash scenario: DSCR becomes irrelevant because there is no modeled debt service, while cap rate and cash yield become the more useful screens.

Rental cash flow stack showing income reduced by vacancy, operating expenses, debt service, and ending pre-tax cash flow.

Vacancy is more than an empty unit. Turnover time, concessions, slower collections, and local market softness all reduce collected income. A stabilized property can justify a lower allowance than a lease-up, but a zero-vacancy assumption rarely leaves enough room for the normal friction of owning rental housing.

Operating expenses need the same discipline. Property tax, landlord insurance, association dues, utilities paid by the owner, recurring services, repairs, management, and reserves usually belong above NOI. Routine maintenance reserves cover smaller repairs. Capital expenditure reserves cover long-cycle replacements such as roof work, heating and cooling equipment, appliances, exterior work, and flooring. Treating all repairs as future surprises can make a property look profitable only because the model has postponed normal ownership costs.

Rental underwriting terms and what each term is useful for
Term	What it answers	Where it can mislead
NOI	How the property performs before financing.	It can look high when reserves, management, or owner-paid utilities are understated.
DSCR	Whether income covers the modeled debt service.	It depends on the loan amount, interest rate, amortization term, and lender's own underwriting adjustments.
Cash-on-cash return	How annual pre-tax cash flow compares with cash invested.	A high percentage can hide a small dollar cushion or aggressive leverage.
Cap rate	How annual NOI compares with purchase price.	It does not include financing, taxes owed by the investor, or future sale proceeds.

Cash flow is a screening measure, not a verdict on whether to buy. Local rent rules, lease quality, tenant concentration, insurance availability, property condition, tax treatment, financing risk, and personal liquidity can all change the decision after the monthly arithmetic looks acceptable.

How to Use This Tool:

Start with a realistic rent roll and acquisition price, then refine the reserves, financing, target screens, and downside tests until the result matches the deal you actually plan to underwrite.

Choose a Deal profile for a starting pattern, or select Custom rental deal after editing. Set Currency symbol first if the memo should display something other than dollars.
Enter Purchase price, Monthly rent, Other monthly income when applicable, and Vacancy allowance. The result should move from Needs valid deal terms once the property has a price and at least one recurring income source.
Set the financing with Down payment, Interest rate, and Loan term. Use a 100% down payment and a zero loan term only when the scenario is all cash.
Add recurring owner costs: Property tax, Insurance, HOA or fixed dues, Maintenance reserve, Management fee, CapEx reserve, Owner-paid utilities, and Other operating expenses.
Include acquisition cash with Closing costs, Initial repairs or rehab, and Initial cash reserve. These inputs affect Cash invested and Cash-on-cash return, even when they do not change NOI.
Open Advanced to tune Target cash-on-cash, Target DSCR, rent stress, vacancy stress, expense stress, rate stress, and Money precision.
Read Deal Snapshot first, then use Underwriting Ledger to inspect line items, Stress Table to test downside pressure, Target Rent Table to see required rents, and Monthly Cash Flow Bridge to visualize the monthly amounts.

If a validation message appears, fix that assumption before reading the tabs. The calculator needs a purchase price above zero, rent or recurring income above zero, and a positive loan term for any financed deal.

Interpreting Results:

Monthly cash flow is the headline pre-tax dollar result after vacancy, operating expenses, reserves, and debt service. It should be read beside Debt service coverage, Cash-on-cash return, Cap rate, and Break-even occupancy. A positive cash flow number is weaker when DSCR is below the selected target, the dollar cushion is small, or the stress rows turn negative.

Rental property result checks and false confidence warnings
Output	Check	Do not overread
Net operating income	Income after vacancy and operating expenses, before debt service.	NOI is not spendable cash when the deal has a loan payment.
Debt service coverage	Annual NOI divided by annual debt service when debt is modeled.	A ratio below 1.00 means NOI does not cover the modeled annual debt service.
Cash-on-cash return	Annual cash flow divided by down payment, closing costs, initial repairs, and reserve cash.	Low cash invested can make the percentage look better while the monthly dollars stay thin.
Break-even occupancy	Share of scheduled income needed to cover modeled expenses and debt service.	A value near or above 100% leaves little room for vacancy, concessions, or collection loss.
Target rent rows	Monthly rent needed for break-even cash flow, target cash-on-cash, target DSCR, and combined-stress break-even.	A required rent above market rent is a deal problem, not just a math problem.

The verdict labels are ordered screening cues. Subsidy risk appears first when monthly cash flow is negative. Debt shortfall appears when NOI fails to cover annual debt service. Below target means cash flow is non-negative but the selected DSCR or cash-on-cash target is not cleared.

Use the Stress Table as the corrective check before trusting a favorable base case. If a modest rent drop, higher vacancy allowance, expense increase, or rate increase turns the deal negative, the base Monthly cash flow number is too fragile to stand alone.

Technical Details:

Rental cash flow modeling begins with gross scheduled income, then applies a vacancy allowance to estimate collected income. In this calculator, the vacancy allowance applies to monthly rent plus recurring other income. Property tax and insurance are entered annually and converted to monthly amounts. Maintenance and CapEx reserves are percentages of monthly rent, while management fee is a percentage of effective gross income.

NOI is calculated before financing so property performance can be separated from the investor's loan structure. Debt service is then subtracted to produce pre-tax cash flow. Cash invested includes down payment, closing costs, initial repairs or rehab, and initial cash reserve, which is why cash-on-cash return can change even when the monthly income statement is unchanged.

Formula Core:

The income statement formulas keep the property cash stack in monthly terms before annualizing the ratios.

\begin{array}{lcl} gross scheduled income & = & monthly rent + other monthly income \\ vacancy loss & = & gross scheduled income \times \frac{vacancy rate}{100} \\ effective gross income & = & gross scheduled income - vacancy loss \\ NOI & = & effective gross income - operating expenses \\ monthly cash flow & = & NOI - monthly debt service \end{array}

For amortizing debt, the monthly principal-and-interest payment uses the standard level-payment formula. If the rate is zero but a loan term exists, the loan amount is divided evenly across the monthly payment count. If the loan amount or term is zero, debt service is zero.

monthly debt service = loan amount \times \frac{i \times {(1 + i)}^{n}}{{(1 + i)}^{n} - 1}

In the debt formula, i is the annual interest rate divided by 12 and converted from percent to decimal form, and n is the loan term in years multiplied by 12. A $420,000 purchase with 25% down creates a $315,000 loan. At 7.25% over 30 years, the modeled monthly debt service is about $2,149.

\begin{array}{lcl} DSCR & = & \frac{annual NOI}{annual debt service} \\ cap rate & = & \frac{annual NOI}{purchase price} \times 100 \\ cash-on-cash return & = & \frac{annual cash flow}{cash invested} \times 100 \\ break-even occupancy & = & \frac{operating expenses + debt service}{gross scheduled income} \times 100 \end{array}

Rental property verdict rules
Verdict	Rule	Meaning
Subsidy risk	Monthly cash flow < 0	Modeled income does not cover expenses and debt service.
Debt shortfall	Annual debt service > 0 and DSCR < 1.00	NOI is below the modeled annual debt service.
Below target	DSCR < selected target or cash-on-cash return < selected target	The deal has non-negative cash flow but misses at least one selected return screen.
Unlevered income	Annual debt service <= 0	The scenario has no modeled debt payment, so cap rate and cash yield carry more weight.
Meets targets	Cash flow is non-negative and selected return screens are cleared	The result clears the current assumptions, subject to market and due-diligence checks.

Stress scenarios change one group of assumptions at a time, then combine rent reduction, added vacancy, higher expenses, and higher interest rate into a downside case. Target rent values are found by testing monthly rent values until each condition is just met: zero cash flow, selected cash-on-cash return, selected DSCR, or break-even under combined stress.

Displayed money values use the selected Money precision, while the calculations use unrounded numbers before display. That can make a copied table differ by a dollar or a few cents from a hand calculation that rounds every intermediate line item.

Responsible Use Note:

The output is an educational underwriting estimate, not financial, legal, tax, lending, or investment advice. It does not model depreciation, investor income taxes, passive activity limits, appreciation, sale costs, refinance risk, irregular repairs, or lender-specific underwriting adjustments. Confirm rent, lease terms, operating costs, loan terms, tax treatment, and local rules before making an offer or committing capital.

Worked Examples:

A duplex case using a $420,000 purchase price, $3,200 monthly rent, $100 other monthly income, 7% vacancy, 25% down, a 7.25% rate, a 30-year term, and the default reserve assumptions produces about $1,592 / mo in Net operating income. The modeled Debt service is about $2,149 / mo, so Monthly cash flow is about -$556 / mo and the verdict is Subsidy risk.

The same duplex profile shows why target rents matter. With those assumptions, the Target Rent Table puts break-even cash flow near $3,967 / mo, the selected 8% cash-on-cash target near $5,231 / mo, and the selected 1.25x DSCR target near $4,707 / mo. If local market rent is still around $3,200, the target rows point to a price, financing, or cost problem.

An all-cash income check changes the interpretation. A $235,000 purchase with $2,100 monthly rent, 5% vacancy, no debt, and reserve-heavy assumptions produces about $1,070 / mo in both Net operating income and Monthly cash flow. Debt service coverage is shown as n/a because no debt is modeled, so Cap rate, Cash-on-cash return, and the stress rows become the useful comparison points.

A troubleshooting case starts with a financed scenario that has a zero loan term, a zero purchase price, or no recurring income. The validation message names the missing assumption, and the result tabs should not be used until Purchase price, Monthly rent or Other monthly income, and Loan term are corrected.

FAQ:

Is NOI the same as monthly cash flow?

No. Net operating income is income after vacancy and operating expenses, before debt service. Monthly cash flow subtracts the modeled principal-and-interest payment after NOI.

Why can positive cash flow still show Below target?

Below target appears when the deal has non-negative cash flow but misses the selected Target DSCR or Target cash-on-cash. Check those targets before treating the verdict as a simple pass or fail.

Where should repairs and reserves go?

Use Maintenance reserve for routine recurring repairs, CapEx reserve for longer-cycle replacements, and Initial repairs or rehab for cash spent before the property is stabilized.

Does the calculator include taxes and depreciation?

It includes property tax as an operating expense, but it does not calculate investor income tax, depreciation, passive loss limits, sale taxes, or depreciation recapture. Treat the result as pre-tax underwriting.

Why did results disappear after changing loan fields?

A financed deal needs a Loan term greater than zero. Use a 100% Down payment with a zero loan term only when modeling an all-cash purchase.

Are my deal assumptions uploaded?

The calculations and exports run in your browser and do not require a rental-data upload or account. Treat copied URLs, screenshots, JSON, and downloaded files as sensitive because they can contain your assumptions.

Glossary:

Gross scheduled income: Monthly rent plus recurring other income before vacancy is applied.
Effective gross income: Gross scheduled income after the vacancy allowance is subtracted.
Net operating income: Property income after vacancy and operating expenses, before debt service.
Debt service coverage: Annual NOI divided by annual debt service when a loan is modeled.
Cash-on-cash return: Annual pre-tax cash flow divided by down payment, closing costs, initial repairs, and reserve cash.
Break-even occupancy: The occupied income share needed to cover operating expenses and debt service.
CapEx reserve: A recurring allowance for long-cycle replacement costs such as roof, HVAC, appliances, and flooring.

References:

Publication 527, Residential Rental Property, Internal Revenue Service, 2025.
Underwritten DSCR, Fannie Mae Multifamily Guide.
Commercial Real Estate, Office of the Comptroller of the Currency, March 2022.

Rental Property Cash Flow Calculator

Current deal signal

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How to Use This Tool:

Interpreting Results:

Technical Details:

Formula Core:

Responsible Use Note:

Worked Examples:

FAQ:

Glossary:

References:

Rental Property Cash Flow Calculator

Current deal signal

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Introduction:

How to Use This Tool:

Interpreting Results:

Technical Details:

Formula Core:

Responsible Use Note:

Worked Examples:

FAQ:

Glossary:

References: