Rental Property Cash Flow Analyzer
Run the numbers on any rental — cap rate, cash-on-cash return, and real monthly cash flow after the mortgage.
Finance tools · Free
About the Rental Property Cash Flow Analyzer
Rental property is a popular path to passive income — and the easiest way to buy a monthly money pit. The difference is the maths you do before you make an offer. This calculator turns a listing into monthly cash flow, cap rate and cash-on-cash return.
Enter the purchase price, down payment, mortgage terms, monthly rent, and your ongoing costs. Then add the expenses most first-time landlords forget: vacancy (roughly 5-8% of rent), maintenance (5-10% of rent), property management (8-10%), taxes, insurance, and HOA.
Gross yield lies; cash flow tells the truth. A headline gross yield can shrink dramatically once vacancy and operating costs come out — and cash flow can turn negative once the mortgage payment is included. Always underwrite the net number.
The 1% rule is a fast filter, not a verdict. Monthly rent should ideally be at least 1% of the purchase price (the "1% rule") to have a chance of healthy cash flow with a mortgage. In expensive markets, most listings fail it — that's a signal to look elsewhere, not to lower your standards.
Cap rate ignores financing; cash-on-cash includes it. Cap rate lets you compare properties on the same footing. Cash-on-cash return tells you what your actual invested dollars earn after the mortgage — which is the number that pays your bills. This is general education, not investment advice.
How to use it
- Enter the purchase price. Enter the agreed price; closing costs go in their own field.
- Set the down payment. Investment properties typically require 20-25% down.
- Enter the mortgage terms. Rate and term determine your debt service.
- Enter monthly rent. Use realistic market rent, not aspirational.
- Add vacancy and operating expenses. Taxes, insurance, HOA, maintenance, management.
- Read cash flow, cap rate and cash-on-cash. Positive cash flow plus a solid cap rate is the goal.
Frequently asked questions
How does the rental property calculator work out monthly cash flow?
It takes your monthly rent, subtracts the vacancy percentage to get effective rent, then subtracts the mortgage principal-and-interest payment and your monthly expenses. With the defaults ($200,000 price, 20% down, 7% over 30 years, $1,800 rent, 5% vacancy, $400/month expenses) the mortgage is about $1,064 and cash flow is about $246 a month.
Why does the cap rate in the rental property calculator ignore my mortgage?
Cap rate is annual net operating income (effective rent minus operating expenses, times 12) divided by the purchase price, so financing is deliberately left out and you can compare properties on equal footing. The default deal works out to $15,720 of NOI and a 7.86% cap rate. The tool flags 6% or higher as a solid starting point, which is a rule of thumb that varies a lot by market.
What counts as cash invested in the rental property calculator's cash-on-cash return?
Cash invested is your down payment plus closing costs, calculated as the closing-cost percentage times the purchase price. Annual cash flow divided by that figure is your cash-on-cash return: about 6.4% on $46,000 invested with the defaults. Repairs, furnishing or reserves you fund at purchase are not included, so bump the closing-cost percentage if you want them counted.
What should I put in the Expenses ($/mo) field of the rental property calculator?
Enter one monthly dollar total covering property taxes, insurance, maintenance, property management, HOA dues and any utilities you pay as the landlord. Convert percentage-based costs to dollars first; for example, 8% management on $1,800 rent is $144 a month. Setting aside something for big replacements like a roof or HVAC keeps the cash flow figure honest.
Does the rental property calculator check the 1% rule?
Not directly. Divide monthly rent by purchase price yourself: the defaults give $1,800 / $200,000 = 0.9%, just under the 1% screen. Treat the 1% rule as a quick filter and rely on the calculator's cash flow and cash-on-cash figures for the actual decision.
Does the rental property calculator include appreciation, depreciation or loan paydown?
No. It is a first-year operating snapshot: there is no appreciation, rent growth, depreciation, income tax or equity from principal paydown, and the full mortgage payment is treated as an outflow. Those factors can change your total return considerably, so treat this as general education, not financial or tax advice, and confirm with a qualified professional.
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