Free real estate investment calculators. Run cash flow, cap rate and cash-on-cash return on a rental, estimate property taxes and escrow, and see if refinancing pays off.
Estimated monthly cash flow
Run the numbers before you make an offer.
Cash flow, cap rate, cash-on-cash and total ROI on a rental property.
Run the deal →Annual tax, effective rate and monthly escrow by state.
Run the deal →Full PITI payment with taxes, insurance and PMI.
Run the deal →New payment, monthly savings and break-even point.
Run the deal →Annual, monthly and total IRS straight-line depreciation on a residential rental.
Run the deal →Great-looking properties can be terrible investments once you account for taxes, vacancy, maintenance and financing. These tools surface the numbers that matter: cash flow, cap rate and return on the cash you actually put in.
Investors throw both terms around like they mean the same thing. They do not. Cap rate is net operating income divided by purchase price, full stop. It has no idea whether you paid cash or financed 95% of the deal. That is the point: cap rate lets you compare a $300,000 duplex to a $1.2 million apartment building on pure earning power, with the mortgage stripped out entirely.
Cash-on-cash return asks a narrower, more personal question: given the actual cash you put down, what did you get back this year? It divides annual cash flow, what is left after the mortgage payment, taxes, insurance and every other expense, by your down payment plus closing costs. Two investors can buy the identical building and post wildly different cash-on-cash numbers depending on how they financed it. A cash buyer's cash-on-cash return equals their cap rate, since there is no loan to separate the two. A leveraged buyer's number moves with the interest rate.
Neither metric alone tells you whether to buy. Cap rate is how you shop; cash-on-cash is how you check whether your specific financing makes the deal work for you.
Take a $220,000 rental with 25% down ($55,000) at 6.75% on a 30-year loan. That is a $165,000 mortgage, which pencils out to $1,070.19 a month in principal and interest.
Rent is $1,950. Knock 5% off for vacancy (nobody stays booked every month of every year) and effective rent drops to $1,852.50. Property tax runs $2,600 a year, or $216.67 a month. Insurance is $1,100 a year, $91.67 a month. Budget 1% of the purchase price annually for maintenance, another $183.33 a month. Hand the property to a manager at 8% of collected rent and that is $148.20 a month gone before you see a dime.
Add it up: $1,070.19 plus $216.67 plus $91.67 plus $183.33 plus $148.20 comes to $1,710.05 in total monthly outlay. Subtract that from the $1,852.50 in effective rent and you are left with $142.45 a month in cash flow, or $1,709.36 for the year. Thin, but positive.
Now the two metrics from above. Annual NOI, rent minus every operating cost except the mortgage, works out to $14,551.60. Divide that by the $220,000 price and cap rate lands at 6.61%. Divide the $1,709.36 in annual cash flow by the $55,000 down payment instead and cash-on-cash return is a much thinner 3.11%. That gap is the cost of the loan showing up in the math. Factor in the roughly $12,842 a year in principal you are also paying down (part of that $1,070.19 monthly payment), and total ROI, cash flow plus equity paydown over cash invested, jumps to 26.46%. The rent check looks unimpressive. The equity building underneath it is not.
Every spreadsheet looks great until a tenant moves out in month four. Vacancy is not a rounding error, it is a recurring cost, and new landlords routinely underwrite as if the unit stays filled every single month of the year. Build in a realistic vacancy allowance from day one instead of discovering it the hard way.
Maintenance gets the same treatment. A property that has not needed a repair in eighteen months is not low-maintenance, it is overdue. Roofs, water heaters and HVAC systems fail on their own schedule, not yours, and skipping a maintenance reserve just moves the expense to whichever month it happens to land on, usually a bad one.
Rate risk is the one people plan for least and feel most. A rental bought with an adjustable rate, or one you plan to refinance "when rates come down," is a bet on a number you do not control. If the deal only works at today's rate, it is worth asking what the monthly payment looks like two points higher before you sign anything.
None of these assumptions are exotic. They are just the difference between a deal that survives a bad year and one that does not.