Rental Property Cash Flow Calculator

Net monthly cash flow, cap rate, and cash-on-cash return. Updated live as you type.

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Your Results

Net Monthly Cash Flow
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Monthly Mortgage (P&I)-
Total Monthly Expenses-
Cap Rate-
Cash-on-Cash Return-
Cash Needed (Down Payment)-

Assumes a 30-year fixed-rate loan. Cash-on-cash return uses the down payment only and excludes closing costs. Estimates for educational purposes, not financial advice.

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The Cash Flow Formula

Cash flow is what is left of the rent each month after every cost of owning the property is paid. It is the single most important number for a buy-and-hold investor, because it tells you whether the property pays you or you pay for the property.

Net Cash Flow = Monthly Rent - (Mortgage + Taxes + Insurance + HOA + Maintenance/Vacancy)

Cap Rate vs. Cash-on-Cash ROI

Both measure returns, but they answer different questions. Smart investors look at both.

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Cap Rate

Cap Rate = Annual NOI / Purchase Price

Measures the property's return as if you paid all cash. NOI (net operating income) is rent minus operating expenses, but not the mortgage. Use it to compare properties and markets on equal footing, regardless of how each one is financed.

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Cash-on-Cash Return

CoC = Annual Cash Flow / Cash Invested

Measures the return on the money you actually put in, after your mortgage payment. Use it to see how leverage changes your returns and to compare a rental against other places you could invest the same cash.

Evaluating a rental deal

How do you calculate cash flow on a rental property, and what is a good number?

Net cash flow = monthly rent - (mortgage + property taxes + insurance + HOA + maintenance/vacancy). Many investors target at least $100-$200 per door per month after all of those expenses. Higher-priced markets often produce thinner cash flow but stronger appreciation, so compare cash flow alongside cap rate and cash-on-cash return rather than in isolation.

How do you calculate cap rate, and what is a good cap rate?

Cap rate = annual net operating income (NOI) / purchase price, where NOI is rent minus operating expenses but not the mortgage. In most US markets, 5%-8% is typical for single-family rentals, with lower cap rates in expensive, high-demand areas and higher cap rates in markets with more risk or slower growth. Cap rate ignores financing, so use cash-on-cash return to see how your loan affects returns.

Should I include vacancy and maintenance in my analysis?

Yes. Leaving them out is the most common reason a deal that looks profitable on paper loses money. A common rule of thumb is to reserve 5%-10% of rent for vacancy and another 5%-10% for maintenance and capital expenses, depending on the age and condition of the property.