Enter the property's purchase price, financing, rental income, and operating costs to estimate monthly cash flow, annual net operating income, and cap rate — the key metrics investors use to screen deals.
Purchase & Financing
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$
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Rental Income
$
%
Typical assumption: 5%–10%.
Operating Expenses
$
Maintenance, utilities, repairs, etc.
$
$
$
Typically 8%–12% of monthly rent if using a manager.
Investment Analysis
Monthly cash flow—
Effective monthly rent (after vacancy)—
Total monthly expenses (incl. mortgage)—
Monthly mortgage payment (P&I)—
Loan amount—
Annual NOI (before debt service)—
Cap rate—
Monthly Cash Flow
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Annual NOI
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Cap Rate
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Cash flow can be negative. Results are estimates for planning purposes. Actual returns vary based on local taxes, maintenance surprises, vacancies, and market conditions.
About the Rental Property Calculator
Before buying a rental property, experienced investors run the numbers to make sure the deal makes financial sense. This calculator evaluates the three metrics that matter most: monthly cash flow (what you keep after all expenses), annual net operating income (property performance before financing), and cap rate (a standardized measure of investment yield). Together, these metrics tell you whether a property is a strong deal or one to pass on.
Key Metrics Explained
Monthly cash flow — Effective rent minus all monthly expenses including the mortgage. Positive cash flow means the property pays for itself and produces income. Negative cash flow means you cover the gap out of pocket.
Effective monthly rent — Gross rent multiplied by (1 − vacancy rate). A 5% vacancy rate on $2,000/month rent yields $1,900 in effective income.
Net Operating Income (NOI) — Annual effective rent minus all operating expenses, taxes, and insurance — but before the mortgage payment. NOI measures property performance independent of how it's financed.
Cap rate — Annual NOI divided by purchase price, expressed as a percentage. A higher cap rate generally means better returns relative to cost, though it may also reflect higher risk or a less desirable location.
Screening deals — Quickly determine if a property's rent and price are in the right ballpark before doing deeper due diligence.
Comparing properties — Run both properties through the calculator and compare cap rate, cash flow, and NOI to identify the stronger investment.
Testing rent assumptions — Adjust monthly rent up or down to see how sensitive cash flow is to changes in market rent.
Evaluating financing scenarios — Change the down payment or interest rate to model how leverage affects cash flow and returns.
Estimating break-even occupancy — Model different vacancy rates to understand how much vacancy the property can sustain before cash flow turns negative.
Local property taxes, insurance rates, maintenance costs, and actual vacancy will vary. This calculator provides planning estimates — not investment advice. Consult a real estate professional or financial advisor before making an investment decision.
Frequently Asked Questions
How do I calculate cash flow on a rental property?
Monthly cash flow equals effective rental income (after vacancy) minus all monthly operating expenses, property tax, insurance, management fees, and the mortgage payment. This calculator computes all of those components and shows net cash flow. A positive result means the property generates income after all costs; a negative result means it costs you money each month.
What is a good cap rate for a rental property?
Cap rate standards vary by market. In high-demand urban markets, investors often accept 4%–6% cap rates because they're betting on appreciation. In smaller markets or higher-risk properties, investors may require 8%–10% or more. There is no universal 'good' cap rate — it depends on your market, risk tolerance, and investment goals.
Should vacancy be included in rental property calculations?
Yes, always. No property stays 100% occupied indefinitely. Vacancy accounts for turnover time, lease gaps, and periods of non-payment. A typical assumption is 5%–10% vacancy, though this varies by market and property type. Ignoring vacancy inflates projected income and can make a weak deal look profitable.
What expenses should I include when analyzing a rental?
Operating expenses typically include property management fees, maintenance and repairs, utilities the landlord pays, lawn care, pest control, and property insurance. Capital expenses (roof, HVAC, appliances) are often handled separately as reserves. This calculator uses a monthly operating expenses field — include all recurring costs you expect to pay as the landlord.
Is a rental property calculator the same as a mortgage calculator?
No. A mortgage calculator only tells you the monthly loan payment for a given loan amount and rate. A rental property calculator goes further — it layers rental income, vacancy, operating expenses, taxes, insurance, and management fees on top of the mortgage to show whether the property generates a profit after all costs.
What is the difference between NOI and cash flow?
Net Operating Income (NOI) measures property performance before debt service — it is effective rent minus all operating expenses but before the mortgage payment. Cash flow subtracts the mortgage payment from NOI. NOI is used to calculate cap rate and evaluate the property independent of financing. Cash flow shows what actually goes into your pocket each month.
Can a property have positive cash flow but still be a weak investment?
Yes. A property might cash flow slightly positive but have a very low cap rate, poor appreciation potential, high maintenance costs not captured in the inputs, or significant deferred maintenance. Cash flow is one metric among many. Experienced investors also look at cash-on-cash return, total return including appreciation, rent-to-price ratio, and local market fundamentals.
